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AA-0944E-TB

January 1977

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Document:	DECsystem10 FORTRAN Programmer's Reference Manual
Order Number:	AA-0944E-TB
Revision:	000
Pages:	360
Original Filename:	AA-0944E-TB_FORTRAN-10_Programmers_Reference_Ver_5_Jan77.pdf

OCR Text

FORTRAN
PROGRAMMEKS
REFERENCE MANUAL

January '1977

This document describes the language elements of the
FORTRAN-10 compiler for the DECsystem-10.

FC)RT'RAN PROGRAMMER'S
REFERENCE MANUAL
OrdE!r No. AA-0944E-TB

SUPERSESSION/UPDATE INFORMATION:

This document supersedes the document of the
same name, Order No. DEC-10-LFORA-D-D,
published June 1975.

OPEnATING SYSTEM AND VERSION:

Any Digital-supported operating system for the
DECsystem-10.

SOFTWARE VERSION:

FORTRAN-10, Version 5

COPi~S

order additional
of this document, contact the Software Distribution]
L..,:enter, Digital Equipment Corporation, Maynard, Massachusetts 01754.

digital ec~uipment corporation · maynard, massachusetts

First Printing,
June 1973
Revised:
Janua.ry 1974
October 1974
May 1975
June 1975
November 1975
January 1977

The information in this document is subject to change without notice
and should not be construed as a commitment by Digital Equipment
Corporation. Digital Equipment Corporation assumes no responsibility
for any errors that may appear in this document.
The software described in this document is furnished under a license
and may be used or copied only in accordance with the terms of such
license.
Digital Equipment Corporation assumes no responsibility for the use
or reliability of its software on equipment that is not supplied by
DIGITAL.

The postage prepaid RE~DER'S COMMENTS form on the last page of this
document requests the user's critical evaluation to assist us in preparing future documentation.
The following are trademarks of Digital Equipment Corporation:

DIGITAL
DEC
PDP
DECUS
UNIBUS
COMPUTER LABS
COMTEX
DDT
DECCOMM

DECsystem-IO
DEC tape
DIBOL
EDUSYSTEM
FLIP CHIP
FOCAL
INDAC
LAB-8
DECsystem-20

8/'17-14

MASSBUS
OMNIBUS
OS/8
PHA
RSTS
RSX
TYPESET-8
TYPESET-IO
TYPESET-II

PREF.I\CC

This ~anual has two parts:
PART I, Introduction to
with SOS, and PART II, FORTRAN-IO Language Manual.

Usin1

FORTRA~-IO

Part I is a short guide to using the DECsystem-IO Operating System.
It describes the ~inimum set of commands necessary to input, edit, anj
eX2cute FORTRAN programs.
It assumes that the reader
has
a
rudimentary knowledge of or is presently learning FORTRAN programming.
It is a guide to implementing FORTR~N on the DECsystem-IO.
The complete

set of Operating System commands
DECsystem-10 Operating Systems Commands Manual
The SOS text editor is described completely in the
(DEC-IO-USOSA-A-D) .

given

the
.
Guide

(DEC-IO-OSCMA-~-D)

SOS

User's

Part II describes the FORTRAN language as implemented for
the
FORTRAN-IO Language Processing System
(referred to as FORTRAN-IO).
The languaqe ;nanual (PART II) is intended for reference purpos2s only.
The reader
is expected to have some experience in writing FORTRA~
programs and to be familiar with the standard FORTRAN language set and
terminOlogy as defined in the American National Standard FOR~RAN,
X3.9-1966.
Descriptions of FORTRAN-IO extensions and aJditions to the
standard FORTRAN language set are printed with 3ray shading.
Operating procedures and descriptions of the DECsystem-IO
environment are included in the appendixes.

iii

programming

MASTER TABLE OF CONTENTS

-rage

PART I

INTRODUCTION TO USING FORTRAN-I0 WITH SOS

CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER

1
2
3
4
5
6

PAW~

7
8

LOGGING I~
TYPING IN YOUR PROGRAM
RUNNING YOUR PROGRAM
CHANGING YOUR PROGRAM
FORTRAN-I0 INPUT AND OUTPUT OF DATA
SOME HELPFUL COMr1AL~DS
SAYING GOODBYE TO THE COMPUTER
EXAMPLES

INTRa 1-1
INTRO 2-1
IL~TRO 3-1
INTRO 4-1
INTRO 5-1
I~\JTRO 6-1
INTRO 7-1
I~TRO 3-1

FORTRAN-I0 LANGUAGE MANUAL

CHAPTER
CHAPTER
CHAPTER

1
2
3

CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
CHAPTER
APPENDIX
APPENDIX
APPENDIX
APPENDIX
APPENDIX
APPENDIX
APPENDIX
APPENDIX

4
5
6

7
8
9
10
11
12
13
14
15
16
A
3

C
D
j~

G
H

INTRODUCTION
CHARACTERS AND LINES
DATA TYPES, CONSTANTS, SYMBOLIC NAMES,
VARIABLES, AND ARRAYS
EXPRESSIONS
COMPILATION CONTROL STATEMENTS
SPECIFICATION STATEMENTS
DATA STATEMENT
ASSIGNMENT STATEMENTS
CONTROL STATEMENTS
I/O STATEMENTS
NAMELIST STATEMENTS
FILE CONTROL STATEMENTS
FORMAT STATEMENT
DEVICE CONTROL STATEMENTS
SUBPROGRAM STATEMENTS
BLOCK DATA SUBPROGRAMS
ASCII-1968 CHARACTER CODE SET
USING THE COMPILER
WRITING USER PROGRAMS
FOROTS
FORDDT
COMPILER MESSAGES
FORTRAN-I0 REALTIME SOFTWARE
FOROTS ERROR MESSAGES

1-1
2-1
3-1
4-1
5-1
6-1
7-1
8-1
9-1

10-1
11-1
12-1
13-1

14-1
15-1
16-1

A-I
B-1

C-l
D-l

E-l
F-l
G-l
B-1

PART I
Introduction to Using FORTRAN-IO with SOS

CONTENTS

Page
I~TRO

1-1

CH,Z\PTER

LOGGING

CHAPTER

TYPING IN YOUR PROGRAM
TO STOP ENTERING LINES INTO YOUR PROGRAM
ENDING OR STORING YOUR PROGRAM(E)
THE RUBOUT OR DELETE KEY (CORRECTING
TYPING MISTAKES)

INTRO 2-1
INTRO 2-2
INTRa 2-2

RUNNING YOUR PROGRAM
THE EXECUTE COMMAND
CTRL/C ("C) (GETTING THE MONITOR'S
ATTENTION
Stopping Your Program's Execution
Deleting a Command
CTRL/U ("U) (CHANGING r.~ LINE)

INTRa 3-1
INTRa 3-1

CHAPTER

CH1\PTER

CHANGING YOUR PROGRAM
THE R SOS COMMAND (CORRECTING MISTAKES IN
YOUR PROGRAM)
SOS COMf.1ANDS
I - Inserting Lines Into Your Program
D - Deleting Lines From Your Program
R - Replacing Lines In Your Program
P - Printing Lines Of Your Program On
The Terminal
N - Changing The Line Numbers
E - End (Ends Editing and Stores
the Program)
EQ - Returning To the Monitor Without
Storing Your Program
A FEW 30S CONVENTIONS
TAB (CTRL/I)
CORRECTING MISTAKES

INTRa 2-3

INTRa
INTRO
INTRa
INTRa

3-3
3-3
3-3
3-4

INTRa 4-1
INTRO
INTRa
INTRa
INTRa
INTRa

4-1
4-1
4-1
4-3
4-3

INTRa 4-4
INTRa 4-5
INTRa 4-5
INTRa
INTRa
INTRa
INTRa

4-5
4-6
4-6
4-6

FORTRAN-IO INPUT AND OUTPUT OF DATA
READ STATEMENT
WRITE STATEMENT
DEVICE UNIT NUMBERS
ACCEPT STATEMENT
TYPE STATEMENT
DATA FILES
Letting FORTRAN Use a Predefined
Filename
Using Your Own Filename

INTRO
INTRO
INTRa
INTRa
INTRa
INTRa
INTRa

5-1
5-1
5-1
5-2
5-2
5-2
5-3

SOME HELPFUL COMMANDS
TYPE COMMAND (PRINTING OUT YOUR PROGRAM)
DIRECT COMMAND (LISTING ALL STORED
PROGRAMS AND FILES)
DELETE COMMAND (ERASING A PROGRAM
OR FILE)

INTRO 6-1
INTRa 6-1

INTRa 5-3
INTRa 5-3

INTRa 6-1
INTRO 6-2

CONTENTS (COf\JT.)

Page
RENAME COMMAND (GIVING A PROGRAM OR FILE
A NEw NAME)
CTRL/O (SUPPRESSNG PRINTED OUTPUT)
GRIPES
CHAPTER

CHAPTER

INTRO 6-2
Ir\lTRO 6-2
I~TRO 6-2

SAYING GOODBYE TO THE COMPUTER
KJOB COMMAND (LOGGING OUT)
K/F Command (Fast Logout)
HELP Command (Getting Assistance)
WHAT TO DO IF YOU ARE DISCONNECTED FROM
YOUR JOB (ATTACH)
FORGOT YOUR JOB NUMBER? (SYS)

I ~~TRO
INTRO
INTRO
INTRO

EXAI>1PLES

I:~TRO

7-1
7-1
7-1
7-1

7-3
INTRO 7-4

I~TRO

3-1

CHAPTER 1
LOGGING-IN

To begin programming on the DECsystem-10 Timesharing System,
you need an account nu~ber and a password. You may also
need to make a telephone connection to the computer;
if so,
you need the computer's telephone number.
Write this
information here:
Telephone Number: _________
(if needed)
Account Number:
Password:
NOTE
Before logging-in, be sure to read Chapter 7 on KJOB
(logging-out) .
If you do not log out, but merely
disconnect
your
terminal,
the
DCCsystem-lO
accounting system will not know you have finished
and WILL CONTINUE TO CHARGE YOU FOR TERMINAL TIME.
First, make sure that the terminal is turned on to LINE.
If
you are to make a telephone connection to the computer, turn
on the acoustic coupler and then dial the telephone number
to make the connection to the DECsystem-lO.
The computer now may print a few
and will print:

lines

identifying

itself

PLEASE LOGIN OR ATTACH
followed by a line beginning with a period (.). This period
signifies the computer's re~diness to accept your LOGIN
command.
If the computer does not orint a period, type
CTRL/C
(~C).
The
may appear as an t on some ter~inals.
The computer will respond with a period.
NOTE
C

To type CTRL/C, hold the Control (CTRL)
key down
while typing C. This causes the computer to ?rint
the characters -C on the terminal.
In this book,
the symbols -C will mean that you are to type
CTRL/C.
In order to signal the computer system
that you wish to give it a command, you can type
"C. This is your way of getting the computer's
attention so that you can give it your next
command.
INTRO'-l-l

LOGGI~G-IN

MONITOR

Monitor:
In what follows we shall often call the computer
system the monitor;
this is the operating system or
executive program that directs the execution of all the
programs and performs the record-keeping duties for the
computer.
You may

~ow

.LOGIN account
return. )
Example:

number

("<CR)"

<CR)

means

carriage

If your account number were 27,240 you would type

.LOGIN 27,240<CR)
NOTE
We shall use the symbol <CR) to show where you are
to press the RETURN key.
This key may also be
labelled CR or CAR RET and is often referred to as a
"carriage
return".
To
distinguish
between
characters you type and those the computer prints,
uderlining will be used for the characters you, the
user, type.
The monitor will now respond with the lines:
JOB job number
PASSWORD:

system number

TTY terminal

line

number

(The job number is assigned by the monitor.)
PASSWORD

The monitor is now asking for your password.
You should
respond by typing your password and pressing the RETURN key.
Since many users prefer to keep their passwords secret, the
password is not printed.
If your password were the word
TROLL, and if everything you typed were printed, the output
would appear as:
PASSWORD:

TROLL

But what actually appears is
PASSWOF<D:

The monitor sijnals its acceptance of your account number
and password by typing the time, date, and perhaps a
message. Then it types a period (.) indicating that it is
ready to accept your command. What you now have on the page
will look something like this (reme~ber that the underlined
passages are those that you have typed).
Example:

LOG J N

~) 7 ¥ ? 4 () <C R >

JOB 25

R5725D SYS #40/2 TTY106
p (~SSWOf~ II : ________
<-=C-=-R~>
1242

18-NOV-76

THUR

INTRO-1-2

CHAPTER :2
TYPING IN YOUR PROGRAM

To type in your program, you will use an editin1 pro1ram
called SOS. Call SOS by giving the monitor command:

SOS responds with:
F I 1.../::: i:

·'

asking you for the name of your file.
(The computer stores
your program on a disk.) You must give the file a name by
which you and the computer can refer to it - you may think
of this name as the name of your program. This name must be
from one to six letters or digits.
Because the computer can
handle several different computer languages, you must also
declare that this file will be used to store a program
written in FORTRAN language. This is done by extending the
name of your file with the letters FOR. These letters will
be
separated from the filename
(or program name) by a
period. Some examples of filenames in which you may store
programs written for FORTRAN are:
A3PEN.FOR
ASCl:23.FOR
INSI?IR.FOR
Whenever you refer to your program, use its full
extension.

name

with

Now you should type in the name of your file/program.
Exam9le:
(Here
ASPEN. FOR.)
• j=,:

the

name

the

file

program

,::;on< CR>

FILE:

AnPEN.FOR<CR>

SOS will now print:

INPUT:

AnPEN.FOR

00:1.00

(column
and the carriage will move to the correct position
Remember that in a
1) for you to begin typing your program.
FORTRAN program, columns 1 through 5 are reserved for the
INTRO--2-1

TYPI~G

IN YOUR PROGRAM

statement number, column 6 is the continuation field, and
columns 7 through 72 are for
the FORTRAN statement.
The
number 00100 that 30S has printed is not Dart of your
program, but is SOS's line number for the first statement of
your program.
If this first statement is not a numbered or
com~ent statement, you must skip
6
spaces
(to column 7)
before beginning to type in the statement. When you have
typed in the first line of your program, press the RETURN
key, and SOS will print the next line number (in increments
of 100); you may enter the next line of your program.
Thus, when SOS prints a line ~u~ber, you know that it is
ready to accept a line of your program.
(For a fast way of
skipping the label field, see the section on TAB, 9age I~TRO
4-6. )

TO STOP ENTERING LINES INTO YOUR PROGRAM (ESCAPE)
ESCAPE

When you wish to stop entering lines into your program, you
should press the ESCape key (on some terminals labeled ESC,
ALT, ALTMODE, or PREFIX). We shall refer to this key as
ESCape.
Pressing the ESCape key causes a $ to be printed on
the ter;ninal.
Example:
(In this example, the first statement is a comment
the character C is in column 1.)
statement:
""C

FILE: ASPEN.FOR<CR)
INPUT: ASPEN.FClR
00100
C THIS IS AN EXAMPLE.<CR)
00200
TYPE 10<CR)
OO;;~()()
F [1 r~ ~1 (I T .:! ASP E N J ~:; A N ICE P L(I CE TO S I';; J ! ~J..~C~
10
00400
END<CR)
() 0 :::j 0 ()

~I;

*
sos

Note that we have two programs that are already stored in
the computer - the system monitor program and SOS. As you
know, the monitor indicates its readiness to accept your
com;nand by printing a period
(.);
sos indicates its
readiness to accept your co;nmand by printing an asterisk
(*) .
When you press the ESCape key, SOS returns with an
asterisk (*) showing that it is ready to accept a command.

ENDING OR STORING YOUR PROGRAM (E)
It is very important, when you have finished writing your
program,
that you tell SOS you are done and that it should
store your pr03ram until you are ready to use it again. You
respond to SOS's request for a command by typing the End
command (the letter E) and the RETURN key.
Example:

I:: DSI';;C : A~:;PEN + FOr;: J

I~TRO-2-2

TYPING

YOUR PROGRAM

In this example, SOS tells us that the program ~SPEN.FOR has
been stored on the disk
(na;ned DSKC:). Then SOS turns
control over to the monitor, which signals its readiness to
accept your next command by printin~ a period.

N8TE
The SOS END command, E, is essential.
If you donlt
tell SOS to store your file before you return to the
monitor, your program will be lost.
RUBOOT

THE RUBOUT OR DELETE KEY (CORRECTING TYPING

-------

MIST~KES)

If you make a mistake while typing a line,
the RUBOUT
(DELETE or DEL)
key allows you to correct your ~istake
without having to retype the entire line.
Press the RUBOUT
key once for each character you wish deleted.
This causes
the deleted characters to be printed with a backslash
(\)
before and after them. Then, type the correct characters.
Example:

FILE:

ASPN\N\EN.FOR<CR>

In this example, the character IN I has been rubbed out.
Example:

.'
In this example, the RUBOUT key was pressed twice to erase
the unwanted characters PEe
Note also that the deleted
characters are printed in reverse order.
Think of the RUBOUT key as a "backspace plus erasure" key!

INTRO-2-3

CHAPTER 3
RUNNI~G

YOUR PROGRAM

THE
- - -EXECUTE
- - - - -COl\'lMAND
---EXECUTE
----

To execute or cause the computer to follow the
given by the program, command the monitor to:

instructions

.EXECUTE filename.extension<CR>
Example:

/"1(1 IN (.
I... I 1'11< ~

I... OI~D I NG

lLNKXCT ASPEN EXECUTION]
ASPEN IS A NICE PLACE TO SKI!
END OF EXECUTION
CPU TIME: 0.05 ELAPSED TIME: 0.15
EXIT

EXECUTE may be abbreviated to EX.
NOTE
You may have been puzzled at the occurrence of lines
written by the monitor before the actual execution
in the above example. They appear because before
your FORTRAN source program can be executed, it must
be translated or compiled into a machine language
program
(the object program) that the computer can
execute. This is done during the step labeled
FORTRAN:
filename.
This object program, like the
original source program, is stored in a disk file.
Before the program can be executed, a copy of the
compiled or object program must be placed
(loaded)
into the working memory of the computer - this copy
is often called a core image of the object 9rogram.
This is accomplished during the LINK: LOADING step.
Finally, the execution step is performed.

INTRO-]-l

RUNNI~G

YOUR PROGRAM

Few programs will com?lete execution the very first time you
try to execute them.
Do not be discouraged!
Chances are
that the compiler will find at least one mistake in your
pro)ra:n. To help you find your mistake(s), it will type out
a ~essage to you.
For example, suppose that you have made
the following mistake in the program on page INTRO 2-2:
in
the FORMAT statement in line 300 the closing quote has been
omitted. The program would look like this:
(i () :I. () ()

T H I ~:; :r: ~::; ()t~ F XA1'1 P I... E •
TYr'L :I. 0

0") :~:,)OO

00300

:1.0

(J ()·4 () ()

FORMAT (' ASPEN IS A NICE PLACE TO SKI!)
END

An attempt to EXECUTE it will cause the following:
• LX () !:) F' EN" F 0 r« C R>

(,SF'EN
00300
:1.0
FORMAT (' ASPEN IS A NICE PLACE TO SKI!)
?FTNCOL I... I NE: 00300 NO CLO!:) I NO OUOTE IN 1...1 TEf;:AI...
?FTNFI..,.IF LINE! 00300 FOUND END OF STATEMENT ~JHEN EXPECTING A

FOr;:Tr;:I:~N!

") "
U j') II F F J NF n I... f~ n E I... !;)

:1.0
::5 F j:) T A I... E r;: I:~ 0 I:;: SAN D N0

? F T i'I F T I...
f11~ IN.
I... 1 N 1'( !
L 0 i~ DIN G

~J A f:; N I N GS

ll...NKNSA NO START ADDRESS]
EXIT

If the compiler has found errors in your program that make
execution impossible, you will again have to call on SOS to
help you correct your program. Do this by using the R SOS
command discussed in Chapter 4.
NOTE
The com?iler will only print error messages for
cases where the program is not clearly understood.
It is possible to have a program that consists of
valid
FORTRAN statements, but gives the wrong
answers.
For example, suppose you intended to enter
TAX

= RATE*AMOUNT

aut by mistake typed
TAX

= RATE+AMOUNT

INTRO-3-2

RUNNING YOUR PROGRAM
The compiler cannot detect this as an error because
both are possibly valid formulas.
Errors of this
type (logic errors) are the most difficult to find.
The program will run, but the answers will be wrong.
Frequently the author of the program will
read the
statement and see what he meant to write instead of
what he actually wrote.
One extremely valuable
method of finding errors of this kind is to attemot
to explain to someone else why the program should
work.
The act of explaining will often hi3hlight
the error. Another method of locating errors is to
have another programmer "proofread" your code.
CTRL/C ("C)

(GETTING THE MONITOR' 3 ATTENTION)

CTRL/C informs the monitor that you wish to give it a
command.
The monitor interrupts whatever the computer is
doing and prints a period to indicate that it is ready to
accept your command.
To type CTRL/C, hold the Control
(CTRL) key down while typing C.
Stopping Your

p~ogram's

Execution

CTRL/C interrupts a program during execution,
returning
control to the monitor.
Sometimes it is necessary to type
CTRL/C twice to interrupt a program.
Example:

....

.EXECUTE
FO!:\ TF~AN:

A~PEN.FOR<CR~

(.lSPEN

"'C"'C

Deleting a Command
You may also use CTRL/C to delete the line you are presently
typing and return control to the monitor.
Example:

.EXECUTE

ASPEN.FOR~C

Typing "CONT" in answer to a monitor prompt will return
to your previous activity IF AND ONLY IF you have not:
tampered with the core image, OR
caused the FORTRAN compiler image in
overwritten.

core

you

If, for instance, you interrupt the executing program to
send a message to someone on another terminal, you can
I:JTRO-3-3

RUNNING YOUR PROGRAM
return.
If you, say, request a directory activity, then the
FORTRAN compiler is overwritten and you cannot return to
your previous activity.
When in doubt, wait until the
execution is complete, unless you want to restart the
execution anyway.

CTRL/U ("U)

(CHANGING A LINE)

CTRL/U deletes the entire line you are typing and moves the
carriage to the beginning of the next line. You may then
retype the line. Note that CTRL/U only deletes that part of
the line you have typed and not the part the computer
prints, i.e., in the following example the line number is
not deleted. CTRL/U is typed by holding the Control (CTRL)
key down while typing U.
Example:
OJGOO

4 ()
~:; r;: 0 0 T :::: ~:; F;: T 0: n I ~:; C)
'"' U
S r;: 0 0 T :::: ~3 nF~ T (II I ~:; C ) <C R>

O:L900

In this example, CTRL/U deletes your input line, which you
then reenter. CTRL/U does not delete the line number, 1300,
printed by 50S.
If you wish to delete the line entirely, follow CTRL/U
the RETURN key.

INTRO-3-4

with

CHAPTER 4
CHANGING YOUR PROGRAM

THE R SOS COMMAND (CORRECTING MISTAKES IN YOUR PROGRAM)
To correct a mistake in a program, you must return to SOS.
As we saw on page INTRO 2-1, we turn control over to SOS by
commanding the monitor:

SOS responds with:
FILE:

QUAD.FOR<CR>

and we type the filename and extension,
in this case
QUAD. FOR.
But now SOS recognizes that this program already
e~ists and correctly assumes that, instead
of inputting a
file, you wish to edit it. SOS thus types:
E 1:1 J T :

nuI~) II ,. For;:

*
The asterisk (*) indicates that SOS is at your command. The
remainder of this section lists SOS commands that are
essential for typing and editing simple FORTRAN programs.
Use the ESCape to terminate these commands.
SOS
I

COM~1ANDS

I - Inserting Lines Into Your Program
To Insert lines into your program beginning with line
for instance, you give sos the command:

2700,

*J2l00<CR>

SOS types out each line number, and you respond by inserting
the line into the program. When you press the RETURN key
after typing each line, SOS will type the next line number.
( ~~h i sis call ed "I n s e r t l10d e ,•. )
INTRO-4-1

CHANGING YOUR PROGRAM

*1 ·.:."0
:,:.: . 0< C R>
?

_ _ _ _1 F .: D 1 f; C) :::: (), 30 y 40< C R>
40
F:OOTl _.:::: •...•....•
(····B
+ ::>CH(f (DISC»/(:?*f~)<CR>
_._----_.
._.
._--_._----

r.) ~:.::

O::?HO

__ __

~---

()::??O

the
Insert
(ALTMO:)E/PREFIX);
this
ter,l1inal.

Ter~inate

command
causes a

by
$

typing
ESCa~e
to be printed on the

Exa:;)ple:
;Jc:I4000<CR>
(i·4000

04100
::{<:

Note that in the above examples, 30S has numbered the lines
in increments of 100.
The reason for providing this
increment is to allow you room to maneuver - suppose you
have accidentally omitted lines that !TIust now be Inserted,
or suppose you now find it necessary to changes your
original ?rogram.
If you have left out 2 lines that should
have gone between lines 3200 and 3300, you may Insert these
lines by changing the increment size, say, to 20, using the
command:

*I :3 ? :I. 0

~I :,:.: 0

<C R)

This allows you to Insert lines 3210, 3230, 3250, 3270, and
3290 into your program.
The size of the increment is of no
il1portance as long as it is small enough to accommodate all
additional lines.
Each time you change the increment size,
the new size is kept until you change it.
Example:

::iCL3?lO ~I 20<CR>
o J 2 1 0 ~,II:;: 1 T [ .: ~5 y
03230 50 FORMAT

0) I:;: 0 0 T :I. ~I _'l(l.QJ 2< C R>
(' ROOTS ARE',
Fl0.2,
---- - - - -'AND',
- - - - -Fl0.?)<CR)
. - - -..-- ..----

::.:;

If you try to insert a line whose line number
is greater
than or equal to that of the next existing line, SO~; l.vill:
use a different line number, or
ignore the command entirely

L\JTRO-4-2

CHANGING YOUR PROGRAM
D

D - Deleting Lines From Your Program

DELETE

To delete line 500 from your program, type

-----.--

*:D ~.:.iOO <C R>

Example:
*D~.:500< CR>

:I.

LINES (00500/1) DELETED

*
If you wish to delete lines
progra;n, use:

1400

through

1600

from

your

*D:l.4()()~:l.6()O<CR>

Example:
;-j<: D :I. -4 00

t 1 6 () 0< C R>

I... I N E !:)

(0 :I. ·4 00./:1. : :I. (, () 0:>

DEI... E T [ II

*
R

R - Replacing Lines in your Program

REPLACE

The Replace command is a combination of a Delete command
followed by an Insert command. To instruct 50S to delete
line 1700 and to be)in inserting lines at line 1700, usc the
Replace com113nd:
*r~:I.·/()O<CR>

This is equivalent to the
command 11700.

command

01700

followed

the

Example:
>~n:l.?OO<CR>
o :I. "7(0)
6 ()

:I. I... IN E S

F CJ I:;: Nlyr (/ I:;: (] (] T :U; I!, F 1 0 (. 2 ) <C R>
«() :I. ? 0 () /:1.) II [TE T F [ i - -. ---.---.----.--.- ---

*
To replace lines 500 through 700 use:

This is equivalent to 0500:700 com~anding 503 t~ delete
lines
500 through 700,
followed by the com~and 1500
instructing 30S to begin inserting lines at 500.
INTRO-4-3

CHANGING YOUR PROGRAM
Example:
*r~~:.:;OO:
OO~:.:;()O

700< CR>
no

FORMAT ('OGIVE COEFFICIENTS')<CR>
(~:s 9
1 0) ,; 9 f!!, C< C R>
FOF;:MAl (FlO,.2)<CR>

F< E (1 0

00600

OO?OO

:1.0

3 I... T NE~:;

';OO~:500/1 ::007(0)

DEI...ETED

*
If you also wish to change the increment size to 10, usc the
Replace command:
*R1000:l100,lO<CR>

This is equivalent to the
command 11000,10.

co~manj

DlOOO:llOO followed by the

Example:

*R:l.OOO!:l.l00,lO<CR>
01000

0:1.0:1.0

Sr;:OOT

~:;nF~T

DENOM
r;: 0 0 T :l.

:2*A<CR>

(DI~:)C)<CR>

() 1 () 2 ()
( .... B + ~; r~ (] 0 l) /
010:30
1:;:00T2
(-B - SROOT) /
0:1. 040
~Ii
2 1...:1: N E n (0 :I. () 0 () /:1. : 0 :1. :l. 0 ()) DEI... E TED

DEN 0 1'1< C R>
DENOM<CR>

As with the Insert co~mand,
to terminate the
command, use the ESCape as in the above example.

P - Printing Lines of Your Program on the Terminal

If you wish to print line 1300 of your program, type

*F' :1. noo< C R>

Example:
*F'lB()O<CR>
() :1. BO 0

sr<OOT

*
To print lines 2700 through 3000 of your program, use
*F'2?OO:3()OO<CR>

INTRO-4-4

Replace

CIIA~GI :'JG

YOUR

PROGRA~1

Example:
*r'::?)'Oo;: :::,)OOO<CR>

();)"::.'()() -?:6--- r;;OOT
()2GOO
02(/00

03000

vJF~JrE

:":: ·· .. B .I
(~:.:j:,

F eHd"! (d' (.'
GO TO :1.00

(2*()

60)
H [) 0 T

F;;OClT
:r: n I,

F :I. 0 • 2 )

N - Changing the Line Numb2rs

-----

The Nu~ber command instructs SOS to renumber your orogram
beginninq at line 100 in increments of 100. SOS docs not
print anything on the ter~inal.
If you wish to sec the
renumbered program, you must use the Print command.
Exam;?le:

:>\<:N <CR>

E - End (Ends Editing and Stores the program)

END

When you have completed editing your program,
inform SOS
that it should now store your program on the disk by typing
E (end).
If you do not instruct SOS to store your program,
the editing you have just completed will be lost.
Example:

[DSKC:QUAD.FOR[27,240]]

This indicates that the program named QUAD. FOR has been
stored on DSKC:. The End command turns control over to the
monitor, which prints a 9criod to indicate its readiness to
accept your next command.
EQ

EQ - Returning to the Monitor without Storing Your Program

QUIT

If you decide that the current editing session is worthless,
you may return to the monitor without storinq your program
by using the Quit command •

.
'

INTRO--4-5

CHANGING YOUR PROGRAM
Example:
*EQ<CR>

~his

restores the original copy of the program as it was
when you last typed R SOS.
If the program is a new one, it
is deleted since an original program did not exist.

A FEw 50S CONVENTIONS
1.

range of lines is indicated by a colon between the
first and last line numbers of the range, i.e., 500:700.

~ period represents the current line.
delete the current line.

Thus,

Qeans

Example:

FORMAT ('OGIVE COEFFICIENTS')
80
tD.<CR>
1 LINES (00700/1) DELE'fED

00700

*
In the above example the current line is line 700 and it
is deleted.
3.

rAB

An asterisk is used to represent the last line of the
file.
Thus, to instruct SOS to print out your entire
file use:

TAB (CTRL/I)
The TAB or Horizontal Tab (sometimes labeled HT or~)
is
handy when you are entering lines into your program. The
TAB, similar to that on a typewriter, is set at 8-character
intervals.
It moves the carriage to the next column that is
a multiple of 8;
no characters are output on the terminal.
As you know,
a FORTRAN statement must be located within
columns 7 through 72, although it may appear at any point
within this range.
Using the TAB to skip over all or part
of the label field will bring the carriage to column 8,
enabling you to begin your FORTRAN statement in that column.
If your terminal does not have a key labeled TAB, use CTRL/I
instead.
To type CTRL/I, hold down the Control (CTRL) key
while typing I.
CORRECTING MISTAKES
To correct one or more characters use the
page INTRO 2-3) .

RUBOUT

key

(see

To change an entire line use CTRL/U (see page INTRO 3-4).

INTRO-4-6

CH~NGING

YOUR PROGRAM

Example:

I2000<CR>

In the above example, CTRL/U (-U) allows you to
com man d .. 0 e 1 e t 2' 1 i n e 1 5 0 0 to ani n s e r teo mon and.

chan~e

the

Example:
<. r~

SOS<CR>

F I I... E: l ELIt A• F 0 F~< CR>
I NF'UT: ZEI... Di~. FOH
00100
C THIS F'HOGHAM DOES NOTHING.<CR>
00200
TYPE 10<CR>
00300
10
FOHMAT (' IT/S WORKING! ')<CR>
00400
TYE\E\PE _~~()< CR>
()()~.)O()

*P4()O<CR>
00-40()

*I !::jOO< C R>
OO!::j()()

00600

00/00
00000
00900
0:1.000
*r;:<;()()~

() 0 <; () 0

FORMAT (' WHAT IS YOUR NAME?')<CR>
ACEF'T 30y YOHNAM ~U
ACCEPT 30, YORNAM<CR>
30
FORMAT (A5)<CR>
~----=T-Y""":P=E-4 (), YOF~ NtlM< CR>

. :. 4. :;. O_ _ _.:. -.F. : ;.O.:. .:F;:.;. . :.t1.;. . :.A- '. .T
',Ii
-40

F [) r~ MPI T

!::i 0

TYPE 50<CR>
F (] I:~ f1 PI T (~
END<CR>

O:l.2()()
0:1. :'500

(' () I Y

(~ () H I y I

'!'

A!:59

A ::.:.i !'

DO YDE

It (]

E()l'lJ~.2.s_~13.~

YO LI' ) <C R >

WAN T TO n E F f< lEN D. s 'i' : __L~_C R>

~I;

:I. LINES (0090()/:I.) DELETED
*I:~<;()() : :I. :I. 00< CR>
() 0 <; 0 0
-4 ()
F (] I:;: t1 () T ( ! 0 HI,
010()()

, HI?

():l.O()()
() :I. :I. 00

TYPE 20

I~::i!,

WA NT TO B I~: . F I:~ IF N r~lU.: ~.:: ~B 2

3 LINES «)O<;OO/:l.:O:l.:l.OO) DELETED
*N<CR>
*POTI<CR>
OO:L()O
r THIS PROGRAM DOES NOTHING~
002()()
TYPE 10
003()O
:1.0
FOF:MAl (' IT" 'S l4CH<KING!')
00400
TYPE ;.~O
o() !:;O 0
20
FORMAT (' WHAT IS YOUH NAME?')
006()O
ACCEPT 30~ YORNAM
00700
30
FORMAT (A5)
TYPE -40, YOI:;:NAM
OOBOO
00<;00
40
F (] r~ MAT (' () HI" ' ¥ A!:; y "
WAN T TO BE: F I~: lEN It !:)? / )
01000
END
*E<CR>

[DSKC:

ZELDA~FORJ

INTRO--4-7

CHANGING YOUR PROGRAM
Let us look at the above example in detail.

Commands the monitor to turn
program SOS.
F J I... E :

control

over

INPUT:

editor

edit.

You
FOR.

Z E I... D A ,. F 0 I:;~< C R>

SOS requests the name of the file you wish to
respond with the name of your file or program:

00100

the

ZELl)~~.

ZEI...D(). Fnr:;~
C THIS PROGRAM DOES NOTHING.<CR>

When SOS fails to find a file by this name,
it concludes
that you intend to create a new file.
SOS then prints the
name of the file and the first line nu~ber.
Now you are
ready to enter the first line of the program.

TYPE :l.O<CR>

00200

Each time you finish typing a line and press the RETURN key,
SOS prints out the next line nu~ber so that you ~ay input
that line.
In typing line 200, the first character actually
typed was a TAB (CTRL/I), which caused the label field to be
skipped over;
this avoids the necessity of counting spaces
so that our FORTRAN statement would begin in the proper
column. TAB is a non-printing character.
00300

FOr:~MAT

(' IT"

WOr;~I\:rNG!"

)<CR>

This statement is labeled.
~fter
typing the
FORTRAN
statement label
(10), you type the non-printing character
TAB (CTRL/I) to skip over the remainder of the label field.
Remember that the first character of a printing FORMAT
statement must be the carriage control (here a blank, which
means single space output). ~otice that because apostrophes
are used to enclose literal fields, they are not allowable
characters within a literal
field but must instead be
represented by two successive apostrophes.
In other words,
although line 300 appears in the program with two successive
aoostrophes (ITIIS), in the execution it causes the word
ITIS to be printed (see the EXECUTION which follows).

TYE\E\PE 20<CR>

004()()

Again, a non-printing TAB is used here to
label field.
The RUBOUT key erases the E.

00500

skip

over

the

lines

into

the

The ESCape key
program.

terminates

the

*P400<CR>
INTRO-4-8

input

CHANGING YOUR PROGRAM
SOS is now ready for a new
line 400 .

You

ask

lines

into

your

co~mand.

."
00400

TYr'L 20

sos prints line 400.

*J !',)OO< C R>
Your next step is to
beginning with line 500.

o0 !',',; 0 0

FORMAT

--'------,

insert

9rogram

WHAT IS YOUR NAME?/)<CR>

---------

You type line 500 into your program.
00600

After typing in line 600 but before pressing the RETURN key,
you 9ause and notice that you have missoelled ACCEPT.
CTRL/U
("U)
:leletes the line, which you" then
retype
beginning with the non-printing TAB.
00'/00

OOBOO
00900

....

You enter lines 700 throu3h 900 into your program and
terminate the insert.
The carriage control
• O' in the
FORMAT statement causes the output to be double spaced.

At this point, you decide to replace line 900.
The R900
command causes it to be deleted and initiates an Insert
command beginning with line 900.
oo<)()O
0:1.000

00:',00
0:1.200
() :I. ;'5 () ()
1 I... I NES

_4_0_ _ _F 0 r~ MA T (' 0 HI, I Y A ~:j ? I , II 0 __ Y 0 t:L~ )<C R >
TYPE ~,')()< CR>
-!:j-O---'-::'(-)-H-M AT ('
__ ~A f'LLJJL B ~_F HI EN DB? I ) <C R>
_ _ _ _E_'N,D<CR>

(00<'100/:1.)

DELETED

when you use the ESCape key to terminate the insert command
(initiated by the replace com~and), SOS informs you that one
line (line 900) has been deleted.
*W'lOO: :1.1. 00< C R>

INTRO--4-9

CHANGING YOUR PROGRAM
You decide to replace lines 900 through 1100.
00 '?OO

·_4.:.:..0_~F~O-,-,F;;:..:..M:..:..AT

(I OJ-.! I :' I:,

1~~:5:,":,

o 1 000

~Ii

:::~;

(009 () () ./ :1. t 0 :I. :I. 00 )

fiELETED

Line 900 is replaced and the
confirms that three lines
deleted.

C Offiill and

L I 1'./ E S

~JANT

TO BE FI:;; J ENP~:;? I )~_~B>_

is terminated.
SOS
thrnugh 1100) have been

(900

30S is now asked to renumber the lines
and in steps of 100.

beginning

with

100

sos to store

your

IF'O:*<CR>
------

You instruct SOS to print out your entire program.
*E<CR>

To conclude the editing session, instruct
program on the disk.

Your program has been stored on DSKC:.
in control.
The EXECUTION of the above program:
!.

EX ZELDA. FOr;;< C R>
ZELDA

FOI:;;TF;:I~N:

M(.UN.
I... I NI';; :
LOAD I NO
I:: Lr·!I~:XCT ZELDA EXECUT ION:]
IT.' S (")01:<1'< I NG !
WHAT IS YOUR NAME?

I..IAL<CR>
---

HI ~

HAL

t..J()NT TO BE

FF~IENDS?

END OF EXECUTION
CPU TIME:

0.10 ELAPSED TIME:

EXIT

INTRO-4-l0

10.20

The monitor

now

CHAPTER 5
FORTRAN-IO INPUT AND OUTPUT OF DATA

Although FORTRAN-IO is essentially the same as stanJard
FORTRAN, a few minor differences do arise in statements that
involve the input and output of data.
F~EAD

READ

STATEMENT

'The statement
READ (u,f)list
where u=device unit number and
f=FORMAT statement number
reads data from the device with unit number u (refer to the
section on Device unit Numbers, below) according to the
specifications given by FORMAT statement f.

Example:

READ (5, 35) IGRADE
(I :.~ :>

OOBOO

F 0 F< MAT

OO?OO

II~RITE

This has the form
WRITE (u,f)

list

where u=device unit number and
f=FORMAT statement number
Example:

O:l.O()()
0:1. :I. () ()

WRITE (1, 30) (STUDNT(I),I=:l.v8)y IGPADE
30

FOI:;:MAT

(SA:::;,

13)

NOTE
The ERR option of the OPEN and CLOSE statements is
also applicable to the READ and WRITE statements.
Refer to Chapter 12

.'
INTRO-·5-1

FORTRAN-IO INPUT AND OUTPUT OF DATA
DEVICE UNIT NUMBERS
In READ and WRITE statements, we ~ust specify to which
we are
device
(Disk,
Line
Printer, Terrainal, etc.)
referring.
For the DECsystem-IO, the device unit nu~bers,
u,
are unifor~ - they are the same on all DECsystem-lOs.
The ~ost commonly used are:
Device Unit

Device
Disk

Card Reader

Line Printer

Terminal

(For a complete list see FORTRAN-IO Language

Nu~ber,u

Manual,

Table

10-1. )

Tnus, WRITE (5,7)
causes out9ut to be printed on your
terminal;
READ (1,25) causes data to be read from the disk.
ACCEPT STATEMENT
ACCEPT

To input data from the terminal you may use
ACCEPT f,list
where f=the FORMAT statement number.
Examt?le:
O() ~:;O ()

00600

ACCEPT 209 IGRADE
FOr;: M(l T (I 3 )

Thus, "ACCEPT f,list" is equivalent to "READ (5,f) list".
TYPE STATEMENT
TYPE

To have output typed on your

ter~inal

use

TYPE f,list
where f=the FORMAT statement number.
Example:
00200
0030()

:1.0

TYPE :1.0
FORMAT ('ASPEN IS A NICE PLACE TO SKI!')

Thus, "TYPE f,list" is equivalent to "WRITE (5,f) li:3t".
NOTE
To print something on your terminal, you must include a
carriage control character similar to the way you do for
a line prnter.
For example, to print the word HELLO on
your terminal, use the format statement below:
00200
003()()

:1.0:1.

TYPE lO:/.
FORMAT (' HELLO')
INTRO-5-2

FORTRAN-IO INPUT AND OUTPUT OF DATA
The space before HELLO tells the system to
new line.

start

DATA FILES
You may use data files in one of two ways:
~ethod,

In the first
filename.

you let FORTRAN

use

In the second method, you choose the filename
the OPEN statement.

oredefined
by

using

Letting FORTRAN Use A Predefined Filename
There are six Device Unit Numbers for disk files;
whenever
you
use one of them, FORTRAN uses a predetermined filename.
Te device numbers and their filenames are listed below.
Device Unit Number

Filename
FOROl.DAT
FOR20.DAT
FOR2l.DAT
FOR22.DAT
FOR23.DAT
FOR24.DAT

20
21
22
23
24
~OTE

If you omit the filename
from
an OPEN
statement,
FORTRAN
uses
the
filename
corresponding
to
the
device unit number.

Examples:
00200

kll:;:ITE

(:1.,:1.0:1.)

00;300

Writes the value of X in
the
file
FOROl.DAT,
according
to
FORMAT
statement 101.
Reads the value of Y from
the
file
FOR23.DAT,
according
to
FORMAT
statement 109.

Usin] Your Own Filename

OPEN

To use your own filename, place an OPEN statement before the
first
READ or WRITE statement that accesses the file.
The
OPEN statement has the format:
OPEN

(UNIT=n, FILE='filename.ext ' )

n is the device unit number, and filename.ext is the name of
the file you want to use .

.
'

INTRO--S-3

FORTRAN-IO INPUT AND OUTPUT OF

OAT~

Exam?le:

oP [: N

(U N I 'r ::;: :? 0:,

F J I... F :;:: ! T EST. 1:1 AT" )

Instructs FORTRAN to open
the
file
TEST.OAT on
logical unit number 20.
Reads Y from logical unit
20.
(The
file
name implied is the
same
as
the
file name in the
OPEN statement with
the
same
logical
unit
nu~ber

nu~ber.)

After the last READ or WRITE statement that accesses a file,
it
is
recom~ended (though not required) that you include a
CLOSE statement.
The CLOSE statement has the format:
CLOSE

(UNIT=n, FILE='filename.ext')

n is the device unit number, and filename.ext is the
the file you are closing.
Example:
00::'=';00

C I... 0 ~:; [:

(U NIT :::: :? 0 9 F I I... E :::: T EST ,. 1:1 AT
I

)

Closes the file TEST.OAT on logical unit number 20.

INTRO-5-4

na~e

CHAPTER 6
SOME HELPFUL COMMANDS

'rYPE COMMAND (PRINTING OUT YOUR PROGRAM)
TYPE

Usually you will have made many changes in your program.
If
you would like the monitor to TYPE out your program on your
terminal as it now stands, command it to:
.TYPE filename.extension<CR)
Example:

.TYPE ASPEN.FOR<CR)
00100
C THI~:f IS ,!:)N EX,!:)MPI... E ,.
00200
TYPE 10
00300
10
FORMAT (' ASPEN IS A NICE PLACE TO SKI!')
00400
END

DIRECT COMMAND (LISTING ALL THE STORED PROGRAMS AND FILES)
DIE

The DIRECT command causes the monitor to list all the
programs and files stored in disk files under your account
number.
It also lists the length of each program or file in
terms of DECsystem-IO disk blocks
(a disk block is 640
characters) and the data on which each was created.
This
command may be abbreviated to DIR.
Exailple:

ASPEN
i=~EL..
1
(~OF~
:I.
ASPEN
FDI:~
:I.
ASPEN
......
NEv,1
nOR
:.~
I:~EL
nUAD
NEW
FOH
nOI:;:
::.~
nUAD
FOI:;:
SNOW
1
FOI:;:
nUAD
TOTAl... OF l!::j DL. () CI': ~:)
r)

,.)

A'••

A',.

1. B····NOlj .... "7 6
[2"7y240J
DSI<C:
1. B··-NOV····"7 6
18-NOV-"76
18-NOV-"76
<O!:.:;~»
:l.B····NOlj····"76
<055>
1.B-NOV-"76
<O~.:.)!:.'j>
:I. B····NDV····"76
<055>
1.B-NOV-"76
<055>
:l.B-NOV-"76
IN 9 FILES ON DSKC: [2"7,240J

<o!:.=;!:.=;>
<055>
<055>

files belong to the prog r amme r (s) with accoun t
27,240.

The~;e

INTRO-6-1

numbe r

SOME HELPFUL COMMANDS
You may find that files you did not create are also listed.
These may be programs and files created by the computer in
editing and compiling your program. The compiled progra~ is
contained in a file named filename. REL" where the filename
is the same one that you used.
If you have edited your
program there will be a program whose name is identical to
yours except that it has a Q as the first letter of the
extension. This is a backup file containing your program as
it existed prior ~o your most recent editing of it.
Each
time your program is edited, the pr03ram immediately before
editing becomes the backup, and the previous backup - if it
existed - is lost.
In the foregoing example, the only files
explicitly created were ASPEN.FOR, NEW. FOR, SNOW. FOR, and
QUAD. FOR. The backups are ASPEN.QOR, NEW.QOR, and QUAD.QOR.
SNOW.FOR has not been edited, so it has no backup.
II

DELETE COMMAND (ERASING A PROGRAM OR FILE)
DELETE

To erase a file from the disk, command the monitor to:
.DELETE filename.extension<CR>
Example:
.DELETE ASPENtFOR<CR>

F I I...ES DEI... rTED::
I~SPEN (. FOr~

():l

BI...DCI<~:)

FI:~EED

RENAME COMMAND (GIVING A PROGRAM OR FILE A NE~ NAME)
RENAME

To rename a file use the

com~and

.RENAME newfilename.extension

oldfilename.extension<CR>

Examt:>le:
• r~ E N I~I ME E X AMP • F (] r:: :::: ~3 N0 ~J • F [) r~< C R>

F II...ES r::ENAMED:
~)NO~,I • FOI:~

This will cause the
EXAMP.FOR

name

SNOW. FOR

changed

CTRL/O (SUPPRESSING PRINTED OUTPUT)
CTRL/O (~O) stops printed output on the terminal The program
sending the output CONTINUES TO RUN.
Use CTRL/O, for
example, to stop the message of the day during LOGIN or to
stop the monitor as it TYPEs a program you have asked for.
CTRL/O is typed by holding the Control (CTRL) key down while
typing the letter O.

INTRO-6-2

SOME HELPFUL COMMANDS
Example:
~TYPE

ASPEN~FOR<CR>

00100
40200

C THIS IS AN EXAMPLE.
TYPE 10

OOJOO

"'0

Although CTRL/C also stops output on the terminal,
stops program execution.

~=omplaints

GRIPE

also

to the Computer_ - the "Court of Last Resort"

When all else fails and you must 1ripe to someone, GRIPE
the computer by commanding the monitor to:

The computer will respond with:

YES?

(DEPRESS ESCAPE KEY WHEN THROUGH)

Now enter your gripe and press the ESCape key when you have
finishej.
Remember that typing ESCape causes a $ to be
printed.
Example:

YE~:)?
(DEPI:;:E~:)S EnCAPF /\EY ~JHEN THI:;:OUGH)
THIS CONnOLE In ALMOSl OUT OF PAPER.$
THAN/';; YOU

INTRO-6-3

CHAP'rER 7
SAYING GOODBYE TO THE COMPUTER

~JOB

COMMAND (LOGGING-OOT)

To say goodbye to the computer,
(KillJOB) :

com~and

the

~onitor

KJOB

,.I<,JOI-:l<CR>

KJOI3
T~e

monitor will responj with

KILL
Snoulj you now decide to abort the logout, type CTRL/C (~C).
If you still wish to logout, you must instruct the monitor
to kill, preserve, or save each of your disk files.
If a
file
is killed,
it is erased from the computer memory;
saved and preserved files, on the other hand, are retained
in the computer memory.
Preserve and save are essentially
alike except in the matter of protection against inadvertent
loss or destruction.
Preserve, unlike save, protects your
files from accidental destruction by another user who shares
your account number. This may occur if, for instance, the
other user fails to recognize the name of your program
during his logout and,
failing to see any need for its
preservation, kills it. To take advantage of the protection
afforded by the preserve file status, it is best to respond
to the CONFIRM with the letter U:
CONF:r: r:;:rl:

U <CR>

This will automatically preserve any files that have already
been preserved during a previous logout.
After you have
typed in the letter U and pressed the RETURN key,
the
monitor will list the name and storage information of each
unpreserved file stored in your disk area, pausing after
each name for your response.
Following the name of each
file you must respond by typing one of the three commands:
(a)
(b)
(.:)

K
P
S

if you wish to kill the file,
to preserve it, and
to save it.

Please remember the saved or preserved files occupy valuable
s?ace on the disk.
In general, the only files you need preserved have the
eKtension FOR.
If you have no further changes to make in
your program, you may preserve the compiled version
this
will have the extension REL.
INTRO-7-1

SAYING GOODBYE TO THE COMPUTER

NOTE
The DECsystem-IO offers the option of detaching the
ter~inal from your job, thereby freeing the terminal
and the telephone line for another task while your
program is executing.
(This option is, of course,
only used for programs with long execution times;
for details see the DECsystem-IO Operating System
Commands Manual.)
Therefore,
TURNING
OFF
THE
TERMINAL OR BREAKING THE TELEPHONE CONNECTION TO THE
COMPUTER DOES NOT END YOUR JOB, NOR DOES IT STOP THE
COMPUTER CLOCK; ONLY THE COl'-1MAND KJOB WILL DO THIS.
If you should inadvertently hang up without using
KJOB, the computer clock, thinking that you have not
yet completed your
job, will keep ticking and
CHARGING YOU FOR TERMINAL TIME.
So please remember
to USE KJOB BEFORE LEAVING THE TERMINAL.
If you
should be accidentally disconnected, always call
again and end your job properly.
(See page INTRO
7-3. )

Example
+ I\,J(JO<CR>

CONFIF~M:

U<CR>

DSI"\A +
D~:>I';C ~

At>PEN
ASPEN
NEW
nUAD
EXAMP
nUAD
!)NOW
nUAD
NEW
AnPEN
D~31"\n :

···
·

I:~EL

<0::55>

I::"
... J

onl:~

<:()~:;!:5:::-

~:J + BLI':!3

onl:~

<: 0 ::,:; ~,:; :::<O::5!5>
<: () !:5 ~,):::<O!::;:5>
<O!',:;::,:;>
<O!::;!:.:;>

I~EI...

FnF~

+ GOI;:
+ FOr~
+ F()r~

··

FOr~

<O~'.i::'.i:::-

FOF~

<O!5!5>

~:.:j

BLI':~3

+ IlL,",S

5 + BL..I':S
!::j

BLI"\S

~::i + BI...K!3
I::"
"J +

BLI';S
BI...I':S
,J + BI...I"\!:)
I::'
"J + BLI"\!)
1::'

d
I::'

f)<CR>
K<CR>
I"\<CR>
!:><CR>
S<CR>
I«CR>
P<CR>
P<CR>
I"\<CR>
P<CR>

USER [27,240]
LOGGED OFF
DEI...EfED 4 FILES C20 BLOCKS)
!:lAVED FILES (30 flI...OCI"\S:>
F~UNT I ME 32 + 34 SEC

,JOB 25,

KIF Command
KIF

TTY106

:I. 430

:I. B.... NO V.... '76

(Fast Logout)

For a fast logout in which all programs and files are saved,
use
.I\/F<CR>

Although this for~ of the KJOB command has the advantage of
being fast,
you cannot preserve the programs you wish to
keep nor kill those you no longer need.

INTRO-7-2

SAYING GOODBYE TO THE COMPUTER
Example:
~I\/F<CR>

JOB 25yUSER[27y240J LOGGED OFF TTY106 1432 18-NOV-76
SAVED ALl.. F II...ES (:·~O BLOCI"S)
RUNTIME 1~56 SEC
HELP Command (qetting Assistance)
To get assistance during logout, type H (for Help)
monitor will respond.
WHAT TO DO IF YOU ARE DISCONNECTED FROM YOUR JOB
ATTACH

and

the

(~TTACH)

Although this can happen to anyone,
it will ~ost often
happen when the teleohone lines connectinq you and the
computer break that con~ection.
If necessary,
redial
the
telephone number to the computer. Under normal conditions,
the computer will print:
PLEASE LOG I N

OF~

ATTt-leH

You will wish to attach yourself to the job on which you ha~
been working.
To do this you must know its job number.
This is given after your LOGIN command.
For exa~ple, in the
LOGIN example on page INTRO 1-3, the job number is 25.
You may attach to a job by using your account number
.ATTACH job number

[account number]

The programmer with account number 27,240 may attach to
25 by typing:
.ATTACH

job

25 [27y240J<CR>

If the programmer with this account number is the owner or
originator of job 25, the monitor asks for his password.
Otherwise, access to the program is denied.
~s
during
LOGIN,
the password is not printed.
If the password is
accepted, the monitor prints a period and the program~er now
is attached to his job.
Example:
.ATTACH 25 [27,240J<CR>
F' Af) S ~J 0 F~ D: _ _ _ _ _ _<-..:C:R>

NOTE
Account numbers are often called Project-Program~er
Numbers
(PPNs).
In the ATTACH command, the account
number must be enclosed in square brackets [ ].
If
your terminal does not have keys labeled [ and ],
use SHIFT/K for the left square bracket,
[, and
SHIFT/M for the right square bracket, ].

INTRO-'7-3

SAYING GOODBYE TO THE COMPUTER
FORGOT YOUR JOBNUMBER?(SYS)
3YS

Suppose you have for~otten your job number. You have thrown
away your LOGIN, or perhaps you are using a Visual Display
(CRT) terminal and the LOGIN has long since disappeared from
the screen.
What now?
You ~ay find out which jobs are
aeing run under your account number by typing:
.3YS [account number]<CR>

• ~:;Y!:; I:: 2'.1'!, ~240::l <CR>
:?~::.i

DET

:I.

+ h,JC)f{<CR>
.ATTACH 25 [27?240::l<CR>
PASSWORD:
<CR>

Here, the programmer with account number 27,240 wishes to
find out which jobs are logged in under his account number.
The monitor answers that job 25 is logged in under account
number 27,240 and that this job is DETached from a terminal.
Then the programmer ATTACHes to job 25.
The SYS command may be given whether or not the user is
logged in.
If the user is not logged in, the SYS command
auto~atically ends with the KJOB command.

Ir'1TRO-7-4

CHAPTEFt 8
EXAMPLES

Example 1 (Executing a

Pr~grarn

More t:han Once) :

This program computes the roots of the quadratic equation ax +bx+c=O.
~ote
that FORTRAN statement labels ~ay be in any order and also that
carriage control characters are necessary for each of the printing
FORMAT statements.
,. TYT'E DUtil) ,. FCH«CR>
00 :I.·:)o------c----mTf> PI:~OGF;:AM COMPUTES THE F;:OOTS OF A
00200
C
DUADRATIC EQUATION OF THE FORM:

00300
00400

oO::.:.i 00

("'

+ BX

+ C

l,J r;: I T E (::.:j? B() )
FORMAT ('OGIVE COEFFICIENTS')
F~EAD
<::.:j, 10) A, B!I C

00900

FOF~MAT

0:1.000

01:1.00

00600
00700

oonoo

Ol::?OO

01300
01400

01:::;00
01600

01700

c
40

OlBOO
() :1. <Y()O

020()0
O:;?:l.OO
02:200

02300
O:;:.~400
02~50()

0:2600
02700

CALCULATE THE DISCRIMINANT
DISC = B*B - 4*A*C
DO THE RIGHT THING ACCORDING TO THE SIGN OF DISC
IF (DISC) 20, 30, 40
POSITIVE DISCRIMINANT
SROOT
SQRT (DISC)
DENOM
2*f~
I:~OOT 1
( .... B + !:>F~OOT) / DENOM
1:~OOT2
(····13 .... BF;:OOT) / DENOM
WRITE (5, 50) ROOT1, ROOT2
FOF;:Mf.lT 0:' I:':':OOTS I~I:;:E'? FlO.::?, ' AND'? FlO.?)
GO TO lOO

02BOO
02900

(F10~~.~)

O;·~O()O

ZERO DI!:>CRIMINANT
= -13 / (2*A)
WRITE (5, 60) ROOT
FORMAT (' ROOT IS', FlO.::?)
GO TO lO()

ROOT

03:1.00

("'

();·~:?OO

("'

NEGATIVE DI!:>CRIMINANT

03300

WF~JTE

034()()
03:::;00

70
:tOO

FORMAT (' ROOTS ARE COMPLEX')
STOP
END

03600

(::,:;y :to)

Below, this program is EXEcurEd twice.
In the second execution the
words FORTRAN: QUAD are missing because the program has already been
INTRO-8-1

EXAMPLES
co~piled,

The

making it unnecessary for the compile step to be repeated.
program is simply loadeJ into core and executed.
(See page INTRO

3-1. )

.EXECUTE QUAD.FOR<CR>

FOI:~TI:~AN:

c~uAII----

MAIN.
I... I NI\ :
L.OI~D I NG
CLNKXCT QUAD EXECUTION]
G I I)E COEFF I C I ENT::;

2.<CR>
·.-.:1.0. <CR>

l?<CR>
I:;:OOTr; AI:~E
:3TUP

3.00 AND

2.00

END OF EXECUTION
CPU TIME: () .:1.:·5 ELf:':jPSED TIME: lB. 9~:5
EXIT
.EXECUTE QUAD.FOR<CR>
I... I NK :
LOf:':jD I NG
[LNKXCT QUAD EXECUTION]
GIVE COEFFICIENTS
~:.:;. <CR>
.<? (. <CR>
:LO.<CR>
ROOTS ARE COMPLEX
STOP

---

END OF EXECUTION
CPU TIME: 0.12 EI . AP~3ED TIME:
EXIT

Example 2

(R~ading

:I.n.~~()

A Disk File):

Student grades are recorded on a disk file named STDGRA.DES.
Each
record has a student name (40 characters) and his numerical grade (a
3-digit integer). The following program will
read the grad(?s and
compute the mean and standard deviation .

• ~ GBADF FOf~<CR>
001()0
C THIS PROGRAM COMPUTES THE MEAN AND
00200
C STANDARD DEVIATION OF STUDENT GRADEr;
t

00300
00400

OPEN (UNIT=l, FILE='STDGRA.DES')
NUMBER :::: ()
~3UM :::: 0

O()500
00600
00700
OOBOO
O()900

SUMS(~R

O:LOOO

01100

01200

01 ~~OO
Ol400
()1~50()

()160()

01700

~::

1 () y END:::: 1 (0) I GRADE
FORMAT (40X, 13)
NUMBEr< :::: NUMB[]< + 1
SU~1 :::: BUM + I GI:<ADE
SUMSQR = SUMBQR + IGRADE*IGRADE
I::~EAD

(1,

GO TO 20
100

AMEAN = SUM/NUMBER
VARIAN = (SUMSQR - (SUM*SUM) INUMBER)
S T DE IJ :::: S n F~ T (VA r< :r AN)
TYPE 30y NUMBER, AMEAN~ BTDEV
INTRO-3-2

(NUMBER-1)

EXl\lVIPLES

O:J.BO()

(/ ONUrlBE/::: OF ::;TUDENTS :::: y J:-5
MEAN GRADE = I, F6.2 .I
STANDARD DEVIATION = ' y F6.2)
CLOSE (UNIT =:l.y FILE='STDGRA.DES')
END
FOr:~~iAT

0:1.900

:1./
l'

O:,?OO()
O:?:I.()O
02200

• EX GI:~ADE. FOI~:<CR>
r(JI:;:TF;:AN ~ G/:~ADE
I", J NI< :
L I...NI';XCT

LO(ID J NG
Gr:~I~DE EXECUT J ON J

NUMBER OF STUDENTS = 17
MEAN GRADE = BO.29
STANDARD DEVIATION

END OF EXECUTION

CPU T I ME to. 2:'5

ELAPSED T J ME: :I.. O()

EXIT

We are opening a disk file, reading the grades stored in it, and,
closing the file.
(See lines 400 and 2100.)
Note that the logical
unit number given in the OPEN and CLOSE statements (UNIT = 1)
is the
same as that given in the READ statement (line 800) and refers to the
device disk.
Execution starts at statement 400 (the OPEN statement).
There is a
controlled loop at statements 800 - 1300. The last statement executed
is the END statement at 2200.
CONTINUATION LINES
Lines 1300, 1900, and 2000 are one FORTRAN statement, lines 1900 and
2000 being continuations of line 1800. Since TABs have been used at
the beginning of each line to skip over all or part of the label
field,
a way must be provided to inform the computer that the line is
a continuation line.
The rule is:
If the first character (after the TAB)
is
between 1 and 9, then the line is a continuation line.
Example.,:3

any

number

(Writing A Dis_k File).:

The following is the program that created the data file STDGRA.DES.
Notice that in the OPEN, WRITE, and CLOSE statements (lines 500, 1100,
and 1400) the device unit number is an integer variable, IUNIT.
IUNIT
has been given the value 1 (line 400) before it is used.

FILE: WOE.FOR<CR>
EDIT: ~IOE. FOt:;;
*PO:*<CR>
O():/.OO
C THIS PROGRAM ENTERS STUDENT GRADES
00200
C ENTER GRADE OF -:/. AFTER LAST STUDENT GRADE TO END
00]00
DIMENSION STUDNT (8)
IUNIT:::::L
00400
OO~j()()
OPEN (UNIT=IUNITy FILE='STDGRA.DES')
ACCEPT 10y (STUDNTCI),I=:I.,8)
00600
40
F ()r:~MA l (nA~::;)
00700
10
INTRO-8-3

EXAr1PL ES

oonoo
00900
0:1.000
0:1.:1.00
0:1. :~?OO
0:1.300
0:1.400

o l ::,:;00

ACCEPT 20, IGRADE
F U f;: t1 (1 T .; I 3 )
IF (lGRADE .EQ. -:I.) GO TO :1.00
"J r;: I T E (1 UN J T ~ 3 (»
( GT UDNT ( I ) , I :::::J. , B ),
FDF;:M(~T
(BA!:,:,;y 13)

:1.00

CI... 0 ~3 E (l..I N J T :::: I UN IT, F I I... E :::: ' S T II G F;: A + DE ~:)' )

I GF~ AII E

GO TO 40
STOP
END

O:I,60()

'THIS IS THE

END'

*
~ft~r

this ?roJra~ has b~en executed,
the file STDGRA.DES will be
listed by th~ DIRECT co~mand (sec page I~TRO 6-1) and during th~ KJOB
command (se~ pag~ I~TRO 7-1) .
• EX "JOE. FOF~<CR>
"JOE
h(',IN "
FOr;:TF;;(lN:'
I...lNI<~

I:: I...NI<XCT t,JOE EXECUT 1 ON J
GEORGE CLINTON<CR>
U;~<CR>

EI...Br;: I DGE

GEI~:F;:Y<CR>

),3<CR>

DANIEL D. TOMPKINS<CR>
!:)B<CR>
JOHN C(',I...HOUN<CR>
nO<CR>
F;: J CHAF;:D 11. ..JOHNSON<CR>
)'<?<CR>
GEORGE DAl...l...nS<CR>
9!:'=';<CR>

I,J 11... L J () ~i

F~.

1< I NG< C R >

\~:o()<CR>

JOHN BF;:ECI<I NI:~ I DG[<CR>
)')'<CR>
H(-~NN I f: (i I... H(lt-ll... I N<CR>
6!:,:;<CR>

c [) I. :fAX < C R >

~::; CH U Y I... F r;:

??<CR>
1..IENf(Y t,J I 1...~:lOtl<CR>

T7<CR>
WILLIAM WHEfI...ER<CR>
<?f.:.<CR>
CHEnTEI:~

AF~THUI:;:<CR>

BO<CR>
LEVI P. MORTON<CR>
----9:l.<CR>
GARRET HOBART<CR>
B9<CR>
CH A F~ L. E ~) 1:1 A kll:~ S <C R >
,

?~':)<CR>

CHARI...En CURTIS<CR>
?!:':;<CR>
<CR>
=T<'CR>
TH I 13 I 1:'\

THE END

END OF EXECI.lT I ON
CPU

TIME:

0.92

EI...APnED

TIME:

4:21.33

E:x:IT

INTRO-8-4

EXAMPLES
Example 4:
This program prepares grade reports for the students whose grades
recorded on the disk file 3TDGRA.DES .
• TYPE REPORT.FOR<CR>
C PROGRAM TO PREPARE GRADE REPORT
00200
DIMENSION ANAME(8)
OPEN (UNIT=1, FILE='STDGRA.DES')
00400
C PRINT HE,~DINGb
':)O::,:iOO
O()(.OO
FOI~:MtlT (' 0', :::iX,
' STUDENT'" 2lX" , GF~ADE' .>
READ (1" 20" END=50) CANAME(I),,1=1,8), IGRADE
00/00
FOI:;:MAT CBA::,:,i, 13)
00000
WRITE (5" 40) (ANAM[(I)"1=11'8),, IGRADE
O()?OO
FOF;:r-iAT (' .' l' Btl::,:,i l' 1:3:)
0:1,000
40
():I. :1, 00
GO TO 30
CLOSE (UNIT=l)" FILE='STDGRA.DES')
01200
STOp.'
END OF GRADE REPORT'
01300
END
01400

ooioo

• EX I:;:EPOI:':'['. FOI:~<CR>
F:'OF Th:(.)N: r~E POI:;: T
iVjtl IN.
I... 11,:11":::
L()AD I NG
I:: I...NI';XCT I:;:EPOF:T EXECUT I ON::I

GHADE
83
/:3

STUDENT
GECJF;:GE CL J NTON
EI...Df:: I flGE OEI:~I:::Y
DANIEL D. TOMPKINS
..JOHN Ctll...HOUN
RICHARD M • ..JOHNSON
GEOPGE D,:)I"I...,~~:;
[/III...I...IAM R I I';ING
..JOHN BRECKINRIDGE
Hr.,NN I HAl... "IAMI... I N
~:)CHUYLEI:;: COLFAX
HENF::Y klI I...~::ON
[/,1 I L.I... I AM WHEELEr::
CHESTEI:;: AF:THur~
LEIJ IF'.. M(lF~TON
GI~F~F~ET

~,)B

80
19

9::j

7l
6!5
'7'7

7l
96
BS

9:1.

HODAI:~T

CHARLE~:)

9:3

CH()F;:I...E~:;

l~)

Dr,WES
CUF~T IS
END OF' GRADE REPORT

END OF EXECUTION
CPU TIME: 0.68
ELAPSED TIME:
EXIT

1:34.77

Il~TRO-B-5

are

EXAMPLES
E x amp 1 e

(_T r yin q TOR e a dAN 0 n - Exis ten t

F i 1 e) :

Now DELETE the data file containing the students· grades, STDGRA.DES,
and then EXecute REPORT. FOR (the program in Example 4). The READ
statement in line 700 cannot be executed since the file to which it
refers does not exist. The execution is thus aborted •
• DELETE STDGRA.DES<CR>
FILE!:> DELElED:
STDGr(A + DES
() 1 B/... OCI\S FF(EED
.EX REPORT.FOR<CR>
L.OAD I NG
[LNKXCT REPORT EXECUTION]

1...1 NI': :

STUDENT
GRADE
%FRSDAT ATTEMPT TO READ BEYOND VALID INPUT
UNIT~l

NAME
IN.
? ,JOB

DSI\!STDGRA.DES[2?240]<055>/ACCESS~SEQINOU/MODE~ASCII

( L0 C)

(402"703)

< < ... .... ....

« ............

CI~ 1... 1... E I:~

.: I... (] C )

MAIN.+:L:I.(2:~~O)

ABOF~TED

END OF EXECUTION
CPU TIME! 0.35 ELAPSED TIME: 1.22
EXIT

INTRO-3-6

< :H: f~ f;~ GS:> I: AI:~ G T YP E !:) ]
<:1/:::.:;>
LUIUIUJ

PART II
FORTRAN-IO Language Manual

The FORTRAN-IO Language Manual reflects the software as of Version
5
of
the
FORTRAN-IO Compiler, Version 5 of the FORTRAN-IO Object Time
System (FOROTS), and Version 5 of
the
FORTRAN-IO Debug~ing
Program
(FORDDT) .

.
'

CONTENTS

Page
CHAPTER

CHAPTER

PROLOGUE

1-1

1.1

BACKGROUND

1-1

CHARACTERS AND LINES

2-1

2.1
2.2
2.2.1

CHARACTER SET
STATEMENT, DEFINITION, AND FORMAT
Statement Label Field and Statement
Numbers
Line Continuation Field
Statement Field
Remarks
LINE TYPES
Initial and Continuation Line Types
Multi-Statement Lines
Comment Lines and Remarks
Debug Lines
Blank Lines
Line-Sequenced Input
ORDERING OF FORTRAN-IO STATEMENTS

2-1
2-2
2-3
2-3
2-3
2-4
2-4
2-4
2-5
2-5
2-6
2-6
2-6
2-7

DATA TYPES, CONSTANTS, SYMBOLIC NAMES,
VARIABLES, AND ARRAYS

3-1

3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.2.7
3.2.8
3.3
3.4
3.5
3.5.1
3.5.2
3.5.3

DATA TYPES
CONSTANTS
Integer Constants
Real Constants
Double-Precision Constants
Complex Constants
Octal Constants
Logical Constants
Literal Constants
Statement Label Constants
SYMBOLIC NAMES
VARIABLES
ARRAYS
Array Element Subscripts
Dimensioning Arrays
Order of Stored Array Elements

3-1
3-2
3-2
3-2
3-3
3-3
3-4
3-5
3-5
3-6
3-6
3-7
3-7
3-8
3-9
3-10

EXPRESSIONS

4-1

4.1
4.1.1

ARITHMETIC EXPRESSIONS
Rules for Writing Arithmetic
Expressions
LOGICAL EXPRESSIONS
Relational Expressions
EVALUATION OF EXPRESSIONS
Parenthesized Subexpressions
Hierarchy of Operators
Mixed Mode Expressions

4-1

2.2.2
2.2.3
2.2.4
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
2.4
CHAPTER

CHAPTER

4.2
4.2.1
4.3
4.3.1
4.3.2
4.3.3

4-2
4-4
4-7
4-9
4-9
4-9
4-10

CONTENTS

(CONT.)

Page
4.3.4
CHAPTER

CHAPTER

Use of Logical Operands in Mixed Mode
Expressions

4-11

COMPILATION CONTROL STATEMENTS

5-1

5.1
5.2
5.3
5.4

INTRODUCTION
PROGRAM STATEMENT
INCLUDE STATEMENT
END STATEMENT

5-1
5-1
5-1
5-1

SPECIFICATION STATEMENTS

6-1

6.1
6.2
6.2.1
6.3
6.4
6.5
6.5.1

6-1
6-1
6-2
6-3
6-5
6-5

6.6
6.7
6.8

INTRODUCTION
DIMENSION STATEMENT
Adjustable Dimensions
TYPE SPECIFICATION STATEMENTS
IMPLICIT STATEMENTS
COMMON STATEMENTS
Dimensioning Arrays in COMMON
Statements
EQUIVALENCE STATEMENT
EXTERNAL STATEMENT
PARAMETER STATEMENT

DATA STATEMENT

7-1

7.1

INTRODUCTION

7-1

ASSIGNMENT STATEMENTS

8-1

8.1
8.2
8.3
8.4

INTRODUCTION
ARITHMETIC ASSIGNMENT STATEMENTS
LOGICAL ASSIGNMENT STATEMENTS
ASSIGN (STATEMENT LABEL) ASSIGNMENT
STATEMENT

8-1
8-1
8-4

CONTROL STATEMENTS

9-1

9.1
9.2
9.2.1
9.2.2
9.2.3
9.3
9.3.1
9.3.2
9.3.3
9.4
9.4.1
9.4.2
9.4.3
9.5
9.6
9.7
9.7.1

INTRODUCTION
GO TO CONTROL STATEMENTS
Unconditional GO TO Statements
Computed GO TO Statements
Assigned GO TO Statements
IF STATEMENTS
Arithmetic IF Statements
Logical IF Statements
Logical Two-Branch IF Statements
DO STATEMENT
Nested DO Statements
Extended Range
Permitted Transfer Operations
CONTINUE STATEMENT
STOP STATEMENT
PAUSE STATEMENT
T (TRACE) Option

9-1
9-1
9-1
9-2
9-2
9-3
9-3
9-4
9-4
9-5
9-6
9-8
9-9
9-10
9-10
9-11
9-12

I/O STATEMENTS

10-1

10.1
10.2
10.2.1
lO.2.2

DATA TRANSFER OPERATIONS
TRANSFER MODES
Sequential Mode
Random Access Mode

10-1
10-1
10-1
10-1

6-7
6-7
6-8
6-9

8-4

CONTENTS (CONT.)

Page
10.2.3
10.3

10.9
10.10
10.10.1
10.10.2
10.11
10.12
10.13
10.14
10.15
10.15.1
10.15.2
10.15.3
10.16

Append Mode
I/O STATEMENTS, BASIC FORMATS AND
COMPONENTS
I/O Statement Keywords
FORTRAN-10 Logical Unit Numbers
FORMAT Statement References
I/O List
Implied DO Constructs
The Specification of Records for
Random Access
List-Directed I/O
NAMELIST I/O Lists
OPTIONAL READ/WRITE ERROR EXIT AND
END-OF-FILE ARGUMENTS
READ STATEMENTS
Sequential Formatted READ Transfers
Sequential Unformatted Binary READ
Transfers
Sequential List-Directed READ
Transfers
Sequential NAMELIST-Contro11ed READ
Transfers
Random Access Formatted READ Transfers
Random Access Unformatted READ
Transfers
SUMMARY OF READ STATEMENTS
REREAD STATEMENT
WRITE STATEMENTS
Sequential Formatted WRITE Transfers
Sequential Unformatted WRITE Transfer
Sequential List-Directed WRITE Transfers
Sequential NAMELIST-Contro11ed WRITE
Transfers
Random Access Formatted WRITE Transfers
Random Access Unformatted WRITE
Transfers
SUMMARY OF WRITE STATEMENTS
ACCEPT STATEMENT
Formatted ACCEPT Transfers
ACCEPT Transfers Into FORMAT Statement
PRINT STATEMEN~r
PUNCH STATEMENT
TYPE STATEMENT
FIND STATEMENT
ENCODE AND DECODE STATEMENTS
ENCODE Statement
DECODE Statement
Example of ENCODE/DECODE Operations
SUMMARY OF I/O STATEMENTS

NAMELIST STATEMENTS

11-1

11.1
11.2
11.2.1
11.2.2

INTRODUCTION
NAMELIST STATEMENT
NAMELIST-Contro11ed Input Transfers
NAMELIST-Control1ed Output Transfers

11-1
11-1
11-2
11-3

10.3.1
10.3.2
10.3.3
10.3.4
10.3.4.1
10.3.5
10.3.6
10.3.7
10.4
10.5
10.5.1
10.5.2
10.5.3
10.5.4
10.5.5
10.5.6
10.6
10.7
10.8
10.8.1
10.8.2
10.8.3
10.8.4
10.8.5
10.8.6

CHAPTER

iii

10-2
10-2
10-3
10-3
10-3
10-6
10-6
10-7
10-8
10-10
10-10
10-11
10-11
10-12
10-12
10-13
10-13
10-13
10-14
10-14
10-16
10-16
10-16
10-17
10-17
10-17
10-17
10-18
10-18
10-18
10-19
10-19
10-20
10-21
10-21
10-22
10-23
10-23
10-23
10-25

CONTENTS

(CONT.)

Page
CHAPTER

CHAPTER

FILE CONTROL STATEMENTS

12-1

12.1
12.2
12.2.1
12.2.2

INTRODUCTION
OPEN AND CLOSE STATEMENTS
Options for OPEN and CLOSE Statements
Summary of OPEN/CLOSE Statement Options

12-1
12-1
12-2
12-10

FORMAT STATEMENT

13-1

13.1
13.1.1
13.2
13.2.1
13.2.2

INTRODUCTION
FORMAT Statement, General Form
FORMAT DESCRIPTORS
Numeric Field Descriptors
Interaction of Field Descriptors
With I/O List Variables
G, General Numeric Conversion Code
Numeric Fields with Scale Factors
Logical Field Descriptors
Variable Numeric Field Widths
Alphanumeric Field Descriptors
Transferring Alphanumeric Data
Mixed Numeric and Alphanumeric Fields
Multiple Record Specifications
Record Formatting Field Descriptors
$ Format Descriptor
CARRIAGE CONTROL CHARACTERS FOR PRINTING
ASCII RECORDS

13-1
13-1
13-2
13-4

DEVICE CONTROL STATEMENTS

14-1

14.1
14.2
14.3
14.4
14.5
14.6
14.7
14.8
14.9

INTRODUCTION
REWIND STATEMENT
UNLOAD STATEMENT
BACKSPACE STATEMENT
END FILE STATEMENT
SKIP RECORD STATEMENT
SKIP FILE STATEMENT
BACKFILE STATEMENT
SUMMARY OF DEVICE CONTROL STATEMENTS

14-1
14-1
14-2
14-2
14-2
14-3
14-3
14-3
14-3

SUBPROGRAM STATEMENTS

15-1

15.1
15.1.1
15.2
15.3

INTRODUCTION
Dummy and Actual Arguments
STATEMENT FUNCTIONS
INTRINSIC FUNCTIONS (FORTRAN-IO DEFINED
FUNCTIONS)
EXTERNAL FUNCTIO;~S
Basic External Functions (FORTRAN-I0
Defined Functions)
Generic Function Names
SUBROUTINE SUBPROGRAMS
Referencing Subroutines (CALL Statement)
FORTRAN-IO Supplied Subroutines
RETURN STATEMENT AND MULTIPLE RETURNS
Referencing External FUNCTION
Subprograms
MULTIPLE SUBPROGRAM ENTRY POINTS (ENTRY
STATEMENT)

15-1
15-1
15-3

13.2.3
13.2.4
13.2.5
13.2.6
13.2.7
13.2.8
13.2.9
13.2.10
13.2.11
13.2.12
13.3
CHAPTER

CHAPTER

15.4
15.4.1
15.4.2
15.5
15.5.1
15.5.2
15.6
15.6.1
15.7

13-6
13-7
13-7
13-10
13-10
13-11
13-12
13-14
13-14
13-15
13-16
13-16

15-3
15-7
15-8
15-8
15-9
15-13
15-14
15-14
15-16
15-17

CONTENTS (CONT.)
Page
CHAPTER

BLOCK DATA SUBPROGRAMS

16-1

16.1
16.2

INTRODUCTION
BLOCK DATA STATEMENT

16-1
16-1

APPENDIX

ASCII-196S CHARACTER CODE SET

A-I

APPENDIX

USING THE COMPILER

B-1

B.l
B.l.l
B.l.1.1
B.l.2
B.2
B.2.1
13.3
13.3.1
13.3.2
13.4

RUNNING THE COMPILER
Switches Available with FORTRAN-IO
The /DEBUG Switch
COMPIL-Class Commands
READING A FORTRAN-IO LISTING
Compiler-Generated Variables
ERROR REPORTING
Fatal Errors and Warning Messages
Message Summary
CREA'I'ING 1\ REENTRANT FORTRAN PROGRM1
WITH LINK-IO

B-1
B-1
B-3
B-4
8-5
B-6
B-17
13-17
13-lB
B-IB

WRITING USER PROGRAMS

C-l

C.l
C.l.l

GENERAL PROGRAMMING CONSIDERATIONS
Accuracy and Range of Double-Precision
Numbers
Writing FORTRAN-IO Programs for
Execution on Non-DEC Machines
Using Floating-Point DO Loops
Computation of DO Loop Iterations
Subroutines - Programming Considerations
Reordering of Computations
Dimensioning of Formal Arrays
FORTRAN-IO GLOBAL OPTIMIZATION
Optimization Techniques
Elimination of Redundant Computations
Reduction of Operator Strength
Removal of Constant Computation From
Loops
Constant Folding and Propagabion
Removal of Inaccessible Code
Global Register Allocation
I/O Optimization
Uninitialized Variable Detection
Test Replacement
Improper Function References
Programming Techniques for Effective
Optimization
INTERACTING WITH NON-FORTRAN-IO PROGRAMS
AND FILES
Calling Sequences
Accumulator Usage
Argument Lists
Argument Types
Description of Arguments
Converting Existing MACRO-IO Libraries
for use with FORTRAN-IO
Mixing FORTRAN-IO and F40 Compiled
Programs
Interaction with COBOL-IO
Calling FORTRAN-IO Subroutines from
COBOL-IO Programs

C-l

APPENDIX

C.l.2
C.l.3
C.l.4
C.l.5
C.l.6
C.l.7
C.2
C.2.1
C.2.1.1
C.2.1.2
C.2.1.3
C.2.1.4
C.2.1.5
C.2.1.6
C.2.1.7
C.2.1.S
C.2.1.9
C.2.2
C.2.3

C.3
C.3.1
C.3.2
C.3.3
C. 3.4
C.3.5
C.3.6
C.3.7
C.3.B
C. 3. B. 1

C-l
C-l
C-2
C-2
C-2
C-3
C-4
C-4
C-5
C-5
C-5
C-6
C-7
C-7
C-7
C-S
C-S
C-B
C-S
C-9
C-9
C-9
C-IO
C-ll
C-12
C-13
C-14
C-20
C-20
C-21

CONTENTS (CONT.)

Page
C. 3.8.2
C.3.9
C.3.9.1
C.3.10
C.3.10.1
C.3.10.2
C.3.10.3
APPENDIX

C-22
C-22
C-23
C-23
C-23

C-25
C-27

FOROTS

D-l

0.1
0.2
0.3
0.4
D.4.1

D-l
D-2
D-3
D-3

D.7
D.8

HARDWARE AND SOFTWARE REQUIREMENTS
FEATURES OF FOROTS
ERROR PROCESSING
INPUT/OUTPUT FACILITIES
Input/Output Channels Used Internally by
FOROTS
File Access Modes
Sequential Transfer Mode
Random Access Mode
ACCEPTABLE TYPES OF DATA FILES AND THEIR
FORMATS
ASCII Data Files
FORTRAN Binary Data Files
Format of Binary Files
Mixed Mode Data Files
Image Files
USING FOROTS
FOROTS Entry Points
Calling Sequences
MACRO Calls for FOROTS Functions
Formatted/Unformatted Transfer
Statements, Sequential Access Calling
Sequences
NAMELIST I/O Sequential Access Calling
Sequences
Array Offsets and Factoring
I/O Statements Random Access Calling
Sequences
Calling Sequences for Statements Which
Use Default Devices
Statements to Position Magnetic
Tape Units
List Directed Input/Output Statements
Input/Output Data Lists
OPEN and CLOSE Statements,
Calling Sequences
Memory Allocation Routines
Software Channel Allocation and
De-allocation Routines
FUNCTIONS TO FACILITATE OVERLAYS
LOGICAL/PHYSICAL DEVICE ASSIGNMENTS

FORDDT

E-l

E.l
E.l.l
E.l.2

INPUT FORMAT
Variables and Arrays
Numeric Conventions

E-2
E-2
E-3

D.4.2
D.4.2.1
D. 4.2.2
D.5
0.5.1
0.5.2
D. 5.2.1
0.5.3
0.5.4
0.6
D.6.1
D.6.2
D. 6.3
D.6.3.1
D. 6.3.2
D. 6.3.3
D. 6.3.4
D. 6.3.5
D. 6.3.6
D. 6.3.7
D. 6.3.8
0.6.3.9
D.6.3.10
D.6.3.11

APPENDIX

Calling COBOL-IO Subroutines from
FORTRAN-IO Programs
LINK-IO Overlay Facilities
Conventions
FOROTS/FORSE Compatibility
FORTRAN-IO/F40 Data File Compatibility
Converting FOROTS Data File to
FORSE-Accepable Form
General Restrictions

D-3
D-4
D-4
D-4
D-4
D-4
D-5
D-5
D-12
D-13
D-13
D-14
D-14
D-15
D-16
D-17
D-18
D-20
D-20
D-22
D-22
D-23
D-26
D-27
D-28
D-29
D-32

CONTENTS (CONT.)

Page
E .1.3
E.2
E.2.1
E.3
E.4
E.5
E.6
E.7
E.8
E.9

Statement Labels and Source Line Numbers
NEW USER TUTORIAL
Basic Commands
FORDDT AND THE FORTRAN-IO /DEBUG SWITCH
LOADING AND STARTING FORDDT
SCOPE OF NAME AND LABEL REFERENCES
FORDDT COMMANDS
ENVIRONMENT CONTROL
FORTRAN-IO /OPTIMIZE SWITCH
FORDDT MESSAGES

E-3
E-3
E-3
E-7
E-7
E-8
E-8
E-17
E-17
E-17

APPENDIX

COMPILER MESSAGES

F-l

APPENDIX

FORTRAN-IO REALTIME SOFTWARE

G-l

G.l
G.2
G.2.1
G.2.2
G.2.3
G.2.4
G.3
G.3.1
G.3.2
G.3.3
G.3.4
G.3.5
G.3.6
G.3.7
G.3.8
G.3.9
G.3.10
G.3.11
G.3.12
G.3.13
G.3.14
G.3.15

INTRODUCTION
USING FORRTF
Core
Modes
Priority Interrupt Levels
Masks
SUBROUTNES
LOCK
RTINIT
CONECT
RTSTRT
BLKRW
RTREAD
RTWRIT
STATO
STATI
RTSLP
RTWAKE
DISMIS
DISCON
UNLOCK
GETCOR, A Temporary Subroutine

G-l
G-2
G-2
G-2
G-2
G-3
G-3
G-3
G-3
G-4
G-4
G-5
G-5
G-5
G-5
G-5
G-6
G-6
G-6
G-6
G-6
G-7

FOROTS ERROR MESSAGES RETURNED BY ERRSNS

H-l

APPENDIX

TABLES
TABLE

1-1
2-1
3-1
3-2
4-1
4-2
4-3
4-4
4-5
4-6
4-7
8-1
10-1
10-2

FORTRAN-IO Statement Categories
FORTRAN-IO Character Set
Constants
Use of Symbolic Names
Arithmetic Operations and Operators
Type of the Result Obtained From
Mixed Mode Operations
Permitted Base/Exponent Type Combinations
Logical Operators
Logical Operations, Truth Table
Relational Operators and Operations
Hierarchy of FORTRAN-IO Operators
Rules for Conversion in Mixed Mode
Assignments
FORTRAN-IO Logical Device Assignments
Summary of READ Statements
vi ~i

1-2
2-1
3-1
3-6
4-1
4-3
4-4
4-5
4-6
4-7
4-10
8-2
10-4
10-25

CONTENTS

(CONT.)

Page
10-3
10-4
1.2-1
13-1
13-2
13-3
13-4
13-5
14-1
lS-l
lS-2
lS-3
B-1
B-2
C-l
C-2
C-3
0-1
0-2
E-l
G-l
H-l

H-2

Summary of WRITE Statements
Summary of FORTRAN-I0 I/O Statements
OPEN/CLOSE Statement Arguments
FORTRAN-I0 Conversion Codes
Action of Field Descriptors On
Sample Data
Numeric Field Codes
Descriptor Conversion of Real and Double
Precision Data According to Magnitude
FORTRAN-I0 Print Control Characters
Summary of FORTRAN-I0 Device Control
Statements
Intrinsic Functions (FORTRAN-I0 Defined
Functions)
Basic External Functions (FORTRAN-I0
Defined Functions)
FORTRAN-I0 Library Subroutines
FORTRAN-I0 Compiler Switches
Modifiers to /DEBUG Switch
Argument Types and Type Codes
Upward Compatibility (FORSE TO FOROTS)
Downward Compatibility (FOROTS TO FORSE)
Function Numbers and Function Codes
FORTRAN Device Table
Table of Commands
Error Messages, Code Format and Full
Message Format
FOROTS I/O Error Messages and ERRSNS
Returned Values
FOROTS Arithmetic and Library Error
Messages

viii

10-17
10-24
12-11
13-3
13-S
13-6
13-8
13-17
14-4
lS-4
lS-10
15-19
B-2
B-3
C-12
C-24
C-26
0-30
0-33
E-l
G-7

H-2
H-S

CHAPTEH 1
PROLOGUE

1. 1

BAC~:GHOUND

The FORTRAN-IO lan3uage set is compatible with and encompasses the
standard
set Jescribed in H7l,merican National Standard FORTRAN,
X3.9-1966" (referred to as the 1966 ANSI standard).
FORTR/\N-IO also
provides many extensions and additions to the standard set that
greatly enhance the usefulness of FORTRAN-IO and increase
its
compatibility with FORTRAN lan)uage sets implemented by other major
computer manufacturers.
In this manual, the FORTRAN-IO extensions and
additions to the 1966 ANSI standard set are printed with gray shading.
A FORTRA~-lO source program consists of a set
of
statements
constructed usin) the language elements and the syntax described in
this manual. A 3iven fORTRAN-lO statement will perform anyone of the
following functions:
1.

It will cause o?erations such as
and branching to be carried out.

It will specify
processed.

It will specify the characteristics of the source oro1ram.

the

type

and

multiplicatiDn,
format

the

division,
data

being

FORTRAN-IO statements are composed of keywords, i.e., words that are
recognized by the com9iler, used with elements of the language set:
constants, variable, and expressions.
There are two basic types of
FORTRAN-IO statements:
executable and nonexecutable.
Executable
statements
specify
the
action
of
the
programi
nonexecutable statements describe the characteristics and arrangement
of data, editing information, statement functions,
and the kind of
subprograms that may be included in the program.
The compilation of
executable statements results in the creation of executable code in
the object program.
~onexecutable statements provide information only
to the compileri
they do not create executable code.
In this manual,
the FORTRAN-IO statements are grouped into 12
categories, each of which is described in a separate chapter. The
na~e, definition, and chapter reference for
each statement category
are given in Table 1-1.
The basic FORTRAN-IO language elements,
(constants, variables,
and
exprc::-ssions), the character set from which they may be formed, and the
rules that govern their construction and use are described in Chapters
2 through 4.

1-1

PROLOGUE
Table 1-1
FORTRAN-IO Statement Categories
Chal?ter
Reference

Category
Name

Description

- - - - - - -. - - - - . - - - - - - - - - . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I

Coml?ilation Control
Statements

Statements
in
this category
identify programs and indicate
and
E?nd i ng
their
beginning
points.

Specification
Statements

Statements
in
this category
declare
the
properties
of
variables, arrays, and functions.

DATA
Statement

This statement
assigns initial
values to variables and array
elements.

A. s s i J n .-,1 e n t

Statements in this category cause
named variables
and/or
array
elements
to
be
replaced by
specified (assigned) values.

Statements

Control
Statements

Statements
in
this
category
determine the order of execution
of
the
object
program
and
terminate its execution.

Input/Output
Statements

Statements
in
this
category
transfer data between internal
storage and a specified input or
output medium.

NAMELIST
Statement

This statement establishes lists
that are
used
with
certain
input/output
statements
to
transfer data that appears in a
special type of record.

file Control
Statements

Statements
in
this
category
identify, open, and close files
and
parameters for
input and
output operations between files
and the processor.

FOI~MAT

This
statement
is
used with
certain input/out9ut statements
to specify the form in·which data
appears in a FORTRAN record on a
specified input/output medium.

Statement

Device Control
Statements

Statements
in
this
category
enable the programmer to control
the positioning of records or
periqheral
files
on
certain
devices.

1-2

PROLOGUE

Table 1-1
(Cont.)
FORTRAN-IO Statement Categories
Chapt(~ r
Reference

Category
Nail1e

Description

Subprogram
Statements

Statements
in
this
category
enable the program~er to define
functions
and subroutines and
their entry points.

BLOCK DATA

thi.s
category
Statements
in
declar(~
data
are
used
to
subprograms that
specification
storage
may initialize com:non
areas.

Statements

1-3

CHAPTER ?
CHARACTERS AND LINES

2.1

CHARACTER SET

Table 2-1 lists the digits,
letters,
and
symbols recognized by
FOHTRAN-IO.
The remainder of the ASCII-196B charact.er set (1), is
acceptable within literal constants or co~~ent t.ext.,
but t.hese
c h a rae t e r :3 C au s e fat a l e r r 0 r s i n 0 the reo n t ext s .
1\ n ex c e p t ion i s
CONTROL-Z, which, when used in Teletype input, means end-of-file.
NOTE
Lower-case
alphabet
characters
are
treated
as
upper-case
outside the
context of Hollerith constants,
literal
strings, and com~ents.
Table 2-1
FORTRAN-IO Character Set
---~----------

Letters
A,a

J,j

B,b

K,k
L,l

C,c
D,d
E,e
F,f

M,m

S,s
T,t
U,u
V,v

N,n

W,w

0,0

x,x

G,g

P,p

Y,y

H,h

Q,q

Z ,z

I ,i

R, r

-- ------------------1

Digits

o
1

5
6

2
3

7
8

------------1. The complete ASCII-1968 character set is defined in
the X3.4-1958
ve r s ion
0 f
the
II Arne r ican
Nat ional
Standard
for
I nfor Ina t ion
Interchanqe,1I and is given in Appendix A.

2-1

CHARACTERS AND LINES
Table 2-1
(Cont.)
FORTRAN-IO Character Set
Symbols

, Comma

Exclamation Point
Quotation Marks
# Number Sign
$ Dollar Sign
& Ampersand
I
Apostrophe
( Opening Parenthesis
) Closing Parenthesis
* Asterisk
+ Plus
!

- Hyphen (Minus)

Period

(Decimal Point)

/ Slant (slash)
: Colon
;

Semicolon

< Less Than
= Equals

Greater Than
>
.Circumflex

Line Termination Characters
Line Feed
Form Feed
Vertical Tab
Line Formatting Characters
Carriage Return
Horizontal 'rab
Blank
Note that horizontal tabs normally advance
the character
position
pointer
to
the next
position
that
is
an even multiple of 8.
~n
exception to this is the initial tab, which is defined as a
tab
that
includes or
starts in character position 6.
(Refer to Section 2.3.1
for a description of initial and sontinuation line types.) Tabs within
literal
specifications count
as one character even though they may
advance the character position as many as eight places.

2.2

STATEMENT, DEFINITION, AND FORMAT

Source program statements are divided into physical lines.
A line
is
defined as a string of adjacent character positions, terminated by the
first
occurrence of
a
line
termination character
regardless of
context.
Each line is divided into four fields:
Line Character Positions ------------------~~

~------V_------~/~'~-------------~---------------~

Statement
Label Field

Continuation
Field

Statement Field

2-2

73.

Remarks

CHARACTERS AND LINES
2.2.1

Statement Label Field and Statement Numbers

You may place a number ranging from 1 to 99999 in the statement label
field of an initial line to identify the statement.
~ny source
pro1ram statement that is referenced by another statement :nust have a
statement number.
Leading zeroes and all blanks in the label field
are ignored, 12.3., the numbers 00105 and 105 are both accepted as
statement number 105.
You may assign the statement numbers in a
source program in any order;
however, each statement number must be
unique with respect to all other statements in the program or
subprogra11.
You cannot label non-executable statements other than
FORMAT and END statements.
~ main program
and a subroutine may contain identical statement
numbers.
In this case, references to these numbers are understood to
mean the numbers in the same program unit in which the reference is
~ade.
An example:

Assu-,Ile that main module r'1AINMD and subprogram SUBI both
contain statement number 105.
A GO TO statement, for
instance, in MAINMD will refer to statement 105 in MAINMO,
NOT to 105 in SUBI.
A GO TO in SUBI will transfer control
to 105 in SUBI.

When you enter source programs into a DECsystem-lO system via a
standard user terminal, you may use an initial tab to skip all or part
of the label field.
If an initial tab is encountered during compilation,
FORTRAN-IO
examines the character immediately following the tab to determine the
type of line being entered.
If the character following the tab is one
of the digits 1 through 9,
FORTRAN-IO considers the line as a
continuation line and the second character after the tab as the first
character of the statement field.
If the character following the tab
is other than one of the digits 1 through 9, FORTRAN-IO considers the
line to be an initial line and the character following the tab is
considered to be the first character of the statement field.
The
character following
the initial tab is considered to be in character
position 6 in a continuation line, and in character position 7 in an
initial line.

2.2.2

Line Continuation Field

Any alj?hanumeric character (except a blank or a zero) placed in
field
(position 6) identifies the line as a continuation line.
Section 2.3.1 for description.)

this
(See

Whenever you use a tab to skip all or part of the label
field of a
continuation line,
the next character you enter must be one of the
digits 1 through 9 to identify the line as a continuation line.

2.2.3

Statement Field

Any FORTRAN-IO statement may appear in this field.
Blanks
(spaces)
and tabs do not affect compilation of the statement and may be used
freely in this field for appearance purposes, with the exception of
textual data given within either a literal or Hollerith specification
where blanks and tabs are significant characters.

2-3

C!IARl\CTERS AND LINES

2.2.4

Remarks

In lines consisting of 73 or ~ore character positions, only the first
72
characters arc interpreted by FORTRAN-IO.
(Note that tabs
'Jenerally occupy lllore than one character position, usu;:llly advancing
the counter to the next character position that is an even multiple of
eight.) All other characters in the line (character positions 73, 74
... etc.) are treated as remarks and do not affect compilation.
i~ote

that remarks may also be added to a line in character positions 7
through 72, provided the text of the remark is preceded by the sy~bol
II!" (Refer to Section 2.3.3.)

2.3
~

LINE TYPES

line in a FORTRAN-IO source program may be:
1.

An initial line,

A continuation line,

A multi-statement line,

comment line,

debug line, or

blank line.

Each of these line types is described in the following paragraphs.

2.3.1

Initial and Continuation Line Types

A FORTRAN-IO statement may occupy the statement fields of up to 20
consecutive lines. The first line in a multi-line statement group is
referred to as the initial line;
the succeeding lines are referred to
as continuation lines.
Initial lines may be assigned a statement number and must have either
a blank or a zero in their continuation line field, i.e., character
position 6.
If you enter an initial line via a keyboard input device, you ~ay use
an initial tab to skip all or part of the label field.
If you use an
initial tab for this purpose, you must immediately follow it with a
non-numeric character, i.e., the first character of the statement
field must be non-numeric.
Continuation lines cannot be assigned statement numbers;
they are
identified by any alphanumeric character (except for a blank or zero)
placed in character position 6 of the line,
i.e., continuation line
field.
The label field of a continuation line is treated as remark
text.
If you are entering a continuation line via a keyboard, you may use an
initial tab to skip all or rart of the label field;
however, the tab
must be followed immediately by a numeric character other than zero.
The tab-numeric combination identifies the line as a continuation
line.

2-4

CHARACTERS AND LINES
Note that blank lines, comments, and debug lines that are treated like
i.e., debug lines that are not compiled with the rest of the
program (refer to Section 2.3.4) terminate a continuation sequence.
com~ents,

Following is an example of a 4-1ine FORTRAN-IO FORMAT statement
initial tabs:
105

using

FORMAT (lHl,17HINITIAL CHARGE = ,FIO.6,10H
COULOMB,6X,
2l3HRESISTANCE = ,F9.3,6H
OHM/ISH CAPACITANCE = ,FIO.6,
38H
FARAD,11X,13HINDUCTANCE
,F7.3,BH
HENRY///
42lH
TIME
CURRENT/7H
MS,10X.2HMA///)
Continuation Line Characters, i.e., 2, 3, and 4

2.3.2

Multi-Statement Lines

You may write more than one FORTRAN-IO statement
in the
statement
field
of one line.
The rules for structuring a multi-statement line
are:

Successive statements must be separated by a semicolon (:).

Only the first statenent in the series can have
number.

Statements following
the
first
statement
continuation of the preceding statement.

The last statement in a line may be continued to the
line if that next line is made a continuation line •

statement

cannot

a
next

An example of a multi-statement line is:
450

DIST=RATE * TIME ;TIME=TIME+O.05 ;CALL PRIME(TIME,DIST)

2.3.3

Conunent Lines and Remarks

Lines that contain descriptive text only are referred
to as comment
lines.
Comment lines are commonly used to identify and introduce a
source program, to describe
the purpose of
a particular
set of
statements, and to introduce subprograms.
To structure a comment line:
1.

You must place one of the characters C (or c),
$,/,*,
or
in character
position 1 of
the
line to identify it as a
comment line.

You may write the text into character positions 2 through the
end of the line.

You may place comment lines anywhere in the
source program,
but they cannot precede a continuation line because com~ents
terminate a continuation sequence.

You may write a large comment as a sequence of any number of
lines:
however,
each line must carry the
identifying
character (C,$,/,*, or 1) in its first character position.

2-5

CHARACTERS AND LINES
The following is an example of a
line.

com~ent

that occupies more

than

one

CSU3ROUTINE - A12
CTHE PURPOSE OF THIS SUBROUTINE IS
CTO FORMAT AND STORE THE RESULTS OF
CTEST PROGRAM HEAT TEST-IIOI
:omment lines arc printed on all listings, but are
the compiler.

otherwise

ignored

You may add a remark to any statement field, in character positions 7
through 72, provided the symbol!
precedes the text.
For example, in
the line
IF(N.EQ.O)STOP! STOP IF CARD IS BLANK
the character group "Stop if card is blank" is identified as a remark
by the preceding!
symbol. Remarks do not result in the generation
of object ~rogram code, but they will appear on listings. The symbol
!,
indicating a remark, must appear outside the context of a literal
specification.
that characters appearing in character positions 73 and beyond
are automatically treated as remarks, so that the symbol
need not
be used.
(Refer to Section 2.2.4.)

~ote

2.3.4

Debug Lines

As an aid in program debugging, a D (or d) in character position 1 of
any line causes the line to be interpreted as a comment line, i.e.,
not compiled with the rest of the program unless the /INCLUDE switch
is present in the command string.
(Refer to Appendix C for a
description of the file switch options.) When the /INCLUDE switch is
present in the command string, the D (or d) in character position 1 is
treated as a blank so that the remainder of the line is compiled as an
ordinary
(noncomment)
line.
Note
that the initial anj all
continuation lines of a debug statement must contain a D (or d)
in
character position 1.

2.3.5

Blank Lines

You may insert lines consisting of only blanks, tabs, or no characters
anywhere in a FORTRAN-IO source program except immediately preceding a
continuation line, because blank lines are by definition initial lines
and as such terminate a continuation sequence. Blank lines are used
for fornatting pur?oses only;
they cause blank lines to appear in
their corresponding positions in source ?rogram listings; otherwise,
they are ignored by the compiler.

2.3.6

Line-Sequence Input

FORTRAN-IO optionally accepts DECsystem-lO line-sequenced files as
produced by LINED or BASIC. These sequence numbers are used in place
of the listing line numbers normally generated by FORTRAN-IO.

2-6

C3ARACTERS AND LINES
2. 4

ORDEI~L~G

OF 2'ORTRAN-lO S'rl\'rE!VIENTS

The order in whicri you place FORTRAN-lO Statements in a program unit
is important.
That is,
certain types of statements have to be
processed before others to guarantee that compilation takes place as
you
expect.
The proper sequence for
FORTRAN-lO statements is
summarized by the following diagram.
----------.--.---------

PROGRAM, FUNCTION, SUBPROGRAM, or
BLOCK DATA Statements
IMPLICIT Statements
PARAMETER Statements

Com:nent Lines

DIMENSION, COMMON,
EQUIVALENCE, EXTERNAL
NAMELIST, or Type
Specification Statements

fORMAT Statements

Statement
Function
Definitions
DAT,I\ Statements
Executable
S t a tel:1 en t s
_ _ _ _ _ _ _ _ _ _- L _

END Statement
-_._---------------------------------'

Horizontal lines indicate the order
in which FORTRAN-lO statements
must appear.
That is, you cannot intersperse horizontal sections.
For example, all PARAMETER statements must appear after all
IMPLICIT
statements and before any DATA statements, i.e., PARAMETER, IMPLICIT,
and DATA statements cannot be interspersed.
Statement function
definitions
must
appear
after IMPLICIT statements and before
executable statements.
vertical lines indicate the way in which certain types of statements
may be interspersed.
For example, you may intersperse DATA statements
with statement function definitions and executable statements.
you
may intersperse FORMAT statements with IMPLICIT statements, parameter
statements, other specification statements, DATA statements, statement
function definitions, and executable statements. The only restriction
on the placement of FORMAT statements is that they must appear after
any PROGRAM,
FUNCTION,
subprogram, and BLOCK DATA statements, and
before the END statement.

2-7

CHARACTERS AND LINES
Special Cases:
1.

The placement of an INCLUDE statement
types of statements to be I~CLUDCd.

dictated

The ENTRY statement is allowed only in
functions
or
subroutines.
All executable references to any of the dummy
para~eters must physically follow the ENTRY statement
unless
the references appear in the function definition statement,
the subroutine, or in a preceding ENTRY statement.

BLOCK DATA subprograms cannot
contain
any
executable
statements, statement functions, FORMAT statement3, EXTERNAL
statements, or NAMELIST statements.
(Refer to Section 16.1.)

When statements are out of place, FORTRAN-lO issues messages, some
which may indicate fatal errors.

2-8

the

CHAPTER 3
DATA TYPES, CONSTANTS, SYMBOLIC NAMES, VARIABLES, AND ARRAYS

3.1

DATA TYPES

The data types you may use in FORTRAN-IO source programs are:
1.

integer,

real,

double-precision,

complex,

octal,

double-octal,

7•

literal,

8•

Btatement label, and

logical.

The use and format of each of the foregoing data types
are
in the descriptions of
the
constant having
the
same
(Sections 3.2.1 through 3.2.8).

3. 2

discussed
data type

CONS1~ANTS

Constants are quantities that do not change value during the execution
of the object program.
The constants you may use in

FORTR~N-IO

are listed in Table 3-1.

Table 3-1
Constants
Category
Numeric
Truth Values
Literal Data
Statement Label

Constant(s)

Types

Integer, real, double-precision, complex, and
octal
Logical
Literal
Address of FORTRAN statement label

L -_ _ _ _ _ _ _ _ _ _ _

.'
3-1

DATA TYPES,
3.2.1

Inte~er

CONST~NTS,

SY~BOLIC

NAMES, VARIABLES, AND ARRAYS

Constants

An integer constant is a string of from one to eleven dijits that
represents a whole decimal number
(a number without a fractional
part).
Integer constants must be within the range of
(-2**35)-1 to
(+2**35)-1 (-34359738367 to +34359733367).
positive integer constants
~ay optionally be signed;
negative integer constants must be signed.
You cannot use decimal points, commas, or other symbols on integer
constants (except for a preceding sign, + or -).
Examples of valid
integer constants are:
345
+345
-345
Examples of invalid integer constants are:
+345.
3,450
34.5

3.2.2

(use of decimal point)
(use of comma)
(use of decimal point;

not a whole number)

Real Constants

A real constant

~ay

have any of the following forms:

A basic

real constant:
a string of decimal di]its followed
immediately by a decimal point followed optionally by a
decimal fraction, e.g., 1557.42.

A basic real constant followed immediately by a decimal
integer exponent written in E notation (exponential notation)
form, e.g., 1559.E2.

An integer constant (no decimal point) followed by a decimal
integer exponent written in E notation, e.g., l559E2.

Real constants may be of any size;
however, each will' be
fit th e pre cis ion 0 f 27 bit s (7 to 9 dec i mal dig its) .

rounded

Precision for real constants is maintained
to approximately eight
si:jnificant digits;
the absolute precision depends upon the numbers
involved.
The exponent field of a real constant written in E notation form
cannot be empty
(blank);
it must be either a zero or an integer
constant. The magnitude of the exponent must be greater than -38 and
equal to or less than +38
(i.e., -38<n< + 38). The following are
exa~ples of valid real constants.
-93.765
7.0E+0
.7E-3
5E+5
50115.
50.El

(7. )

( . 0007)
(500000.)
(500. )

The following are examples of invalid real constants.
72.6E75
.375E
500

(exponent is too large)
(exponent incorrectly written)
(no decimal point given)

3-2

DATh TYPES, CONSTANTS, SYMBOLIC NAMES, VARIABLES,
3.2.3

~ND

ARRAYS

Double-Precision Constants

Constants of this type are similar to real constants written in E
notation form~
the direct differences between these two constants
are:
1.

Double-precision constants, depending on their magnitude,
have precision to either 15 to 17 places (system with a KAJO
Processor) or 16 to 13 places (syste~ with a KIlO or KLIO
Processor),
rather
than the 8-digit precision obtained for
real constants.

Each
double-precision
locations.

The letter D, instead of E,
is used in
constants to identify a decimal exponent.

constant

occupies

two

storage

double-precision

You must use both the letter D and an exponent
(even of zero)
in
writing a double-precision constant. The exponent need only be signed
if it is negative~
its magnitude must be greater than -38 and equal
to or less than +38
(i.e., -38<n +38).
The range of magnitude
permitted a double-precision constant depends on the type of processor
present in your system (on which the source program is to be compiled
and run). The per;nitted ranges are:
Processor

Range

Kl-UO
KIlO or KLIO

1.97 X 10**(-31) to 3.4 X 10**(+38)
0.14 X 10**(-38) to 3.4 X 10**(+38)

The following are valid examples of double-precision constants.
7.9D03
7.9D+03
7.90-3
79D03
79DO

( ~=
( :=
( -( :=
( :=

7900)
7900)
.0079)
79000)
79)

The following are invalid exar:lples of double-precision constants.
7.9099
7.9E5

3.2.4

(exponent is too large)
(IIE" denotes a single-precision constant)

Complex Constants

You can represent a complex constant by an ordered pair of integer,
real, or octal constants written within parentheses and separated by a
comma.
For example,
(.70712, -.70712)
and
(3.763E3,
2.297)
are
co~plex constants.
In a complex constant the first (leftmost) real constant of the nair
represents the real part of the number;
the second real constant
represents the imaginary part of the number.
Both the real and
imaginary parts of a complex constant can be signed.
The real constants that represent the real and imaginary parts of a
co~plex
constant occupy two consecutive storage locations in the
object program.

3-3

DATA TYPES, CONSTANTS, SYMBOLIC NAMES, VARIABLES, AND ARRAYS
Octal Constants

3.2.5

You may use octal numbers
(radix 8)
as constants in arithmetic
expressions, logical expressions, and data statements. Octal numbers
up to 12 diJits in length are considered standard octal constants;
they are stored right-justified in one processor storage location.
When necessary, standard octal constants are padded with leading zeros
to fill their storage location.
If you specify more than 12 di3its in
considered a double octal constant. Double
storage locations and may contain up to
digits;
zeros are added to fill any unused

an octal number,
it is
octal constants occupy two
24
right-justified octal
digits.

If you assign a single octal constant to a double precision or complex
variabLe, it is stored, right-justified, in the high-order word of the
variable. The low-order portion of the variable is set to zero.
If you assign a double octal constant to a double precision or complex
variable,
it is stored right-justified starting in the low-order
(rightmost) word and precedes leftwards into the high-order word.
All octal constants must:
1.

be preceded by a double quote (") to identify the
octal, e.g., 11777, and

be signed if negative, but optionally signed if positive.

digits

contain one or more of the digits 0 through 7, but not

The following are examples of valid octal constants:
"123456700007
"123456700007
+"12345
-"7777
.1-7777

The following are examples of invalid octal constants:
'112368
7777

(contains an 8)
(no identifying double quotes)

When you use an octal constant as an operand in an expression,
its
form
(bit pattern) is not converted to accom~odate it to the type of
any other operand. For example, the subexpression
(A+ 1I 202
400
000
000)
has as its result the sum of A with the floating point number
2.0;
while the sUbexpression (1+'1202 400 000 000) has as its result
the sum of I with a large integer.
Octal constants may not be used as stand-alone arguments for library
functions that require non-octal arguments.
MINO, for instance,
requires INTEGER arguments and cannot accept octal arguments.
When you combine a double octal constant in an expression with either
an integer or real variable, only the contents of the high order
location (leftmost) are used.

3-4

DATA TYPES, CONSTANTS, SYMBOLIC NAMES, VARIABLES, AND ARRAYS
3.2.6

Logical Constants

The Boolean values of truth and falsehood are represented
in
FORTRAN-IO source programs as the logical constants .TRUE. and
.FALSE .. Always write logical constants enclosed by periods as in the
preceding sentence.
Logical quantities may be operated on in arithmetic and lo]ical
statements.
Only the sign bit of a numeric used in a logical IF
statement is tested to determine if it is true (sign is negative)
or
false (sign is positive).

3.2.7

Literal Constants

A literal constant may be either of the following:
1.

A string of alphanumeric and/or special characters
within apostrophes, e.g., ITEST#5 1 •

contained

A Hollerith literal, which is written as a string of
alphanumeric and/or special characters preceded by nH (e.3.,
nHstring).
In the prefix nH, the letter n represents a
number
that
specifies the exact number of characters
(including blanks) that follow the letter Hi
the letter H
identifies the literal as a Hollerith literal. The followin]
are examples of Hollerith literals:
2HAB
14HLOAD TEST #124
6H#124-'A

NOTE
A tab (-f) in a Hollerith literal is counted
character, e.g., 3H-f l~B.

one

You may enter literal constants into DATA statements as a string of:

up to ten 7-bit ASCII characters
precision type variables, and

up to five
variables.

7-bit

ASCII

for

characters

complex
for

all

double

other

type

The 7-bit ASCII characters that comprise a literal constant are stored
left-justified
(starting in the high-order word of a 2-word precision
or complex literal) with blanks placed in empty character positions.
Literal constants that occupy more than one variable are stored as
successive variables in the list. The following example illustrates
how the string of characters
A LITERAL OF MANY CHARACTERS
is stored in a six-element array called A.
DINENSION A(6)
DATA A/IA LITERAL OF MANY CHARACTERS I /

DATA TYPES, CONSTANTS, SYMBOLIC NAMES, VARIABLES, AND ARRAYS
A( 1) is set to 'A LIT',
A (2) is set to 'ERAL
A(3) is set to 'OF MA'
A (4) is set to 'NY CHI
A (5) is set to 'ARACT'
A (}) is set to 'ERS

3.2.8

Statement Label Constants

Statement labels are
statement numbers.

numeric

identifiers

that

represent

program

You write statement label constants as strings of from one to five
decimal digits, which are preceded by either a dollar sign ($) or an
ampersand (&). For exar.tple, either $11992 or &11992 may be used as a
statement label constant.
You use statement label constants only in the argument list of CALL
statements to identify the statement to return to in a multiple RETURN
statement.
(Refer to Chapter 15.)

3.3

SYMBOLIC NAMES

Symbolic names may consist of any alphanumeric combination of from one
to six characters.
You may use more than six characters, but
FORTRAN-lO will ignore all but the first six. The first character of
a symbolic name must be an alphabetic character.
The following are examples of legal symbolic names:
A12345
IAMBIC
ABLE
The following are examples of illegal symbolic names:
#AMBIC
lAB

(symbol used as first character)
(number used as first character)

You use symbolic names to identify specific items of a FORTRAN-IO
source program; Table 3-2 lists these items, together with an example
of a symbolic name and text reference for each.
Table 3-2
Use of Symbolic Names

Symbolic Names
Can Identify
I.
2.
3.
4.
5.

Variables
Arrays
Array elements
Functions
Subroutines
6. External library
functions
7 • COMMON block names

For Example

For a Detailed
Descripti.on
See Secti.on

PI, CONST, LIMIT
TAX
TAX (NAME, INCOME)
MYFUNC, VALFUN
CALCSS, SUB2, LOOKUP
SIN, :1\TAN, COSH

3.4
3.5
3.5.1
15.2
15.5
15.4

DATAR, COMDAT

6.5

3-6

DATA TYPES, CONSTANTS,
3.4

SY~BOLIC

NAMES, VARIABLES, AND ARRAYS

VARI.:t:..BLES

A variable is a datum (storage location)
that is identified by a
symbolic name and is not a constant, an array or an array element.
Variables specify values that are assigned to them by
either
arithmetic statements (Chapter 8), DATA statements (Chapter 7), or at
run time via I/O references (Chapter 10).
Before you assign a value
to a variable, it is termed an undefined variable, and you should not
reference it except to assign a value to it.
If you reference an undefined variable,
will be obtained.

unknown

(']'arbage)

value

The value you assign to a variable may be either a constant or the
result of a calculation that is performed during the execution of the
object program.
For example, the statement IAB=5 assigns the constant
5 to the variable lAB;
in the statement IAB=5+B, however, the value
of lAB at a given time will depend on the value of variable B at the
time the statement was last executed.
The type of a variable is the type of the contents of the
it identifies.
Variables may be:
1.

integer

real

logical

double-precision, or

complex.

datum

that

You may declare the type of a variable by using either
implicit or
explicit type declaration statements (Chapter 6).
However, if you do
not use type declaration statements, FORTRAN-lO assumes the following
convention:
1.

Variable names that begin with the letters I, J, K, L, M,
N are normally integer variables.

Variable names that begin with any letter other than I, J, K,
L, M, or N are normally real variables.

Examples of determining the type of a variable according
foregoing convention are given in the following table:
Variable
ITEMP
OTEr-1P
KA123
AABLE

3 • :::>r-

Beginning Letter
I

the

Assumed Data Type
Integer
Real
Integer
Real

K
A

ARRAYS

An array is an ordered set of data identified by an array name.
Array
names are sy~bolic names and must conform to the rules given in
Section 3.3 for writing symbolic names.

3-7

DATA TYPES, CONSTANTS, SYMBOLIC NAMES, VARIABLES, AND ARRAYS
Each datum within an array is called an array element.
As with
you may assign a value to an array element. Before you
assign a value to an array element it is considered to be undefined;
you should not reference it until you have assigned it a value.
If
you reference an undefined array element, the value of the element
will be unknown and unpredictable (garbage).
variable~,

Name each element of an array by using the array name together with a
subscript that describes the position of the element within the array.

3.5.1

Array Element Subscripts

Give the subscript of an array element identifier within parentheses,
as either one subscript quantity or a set of subscript quantities
delimited by commas. write the parenthesized subscript immediately
after the array name. The general for~ of an array element na~e is AN
(Sl, S2, ... Sn), where AN is the array name and 31 through Sn represent
n number of subscript quantities.
You may use any number of subscript
quantities in an element name;
however, the number used must always
equal the number of dimensions
(Section 3.5.2) specified for the
array.
A subscript can be any compound expression (Chapter 4), for example:
1.

Subscript quantities may contain arithmetic expressions that
involve addition, subtraction, multiplication, division, and
exponentiation.
For
example,
(A+B,C*5,D/2)
and
(A**3,(B/4+C)*E,3) are valid subscripts.

Arithmetic expressions used in array subscripts may be of any
type, but noninteger expressions
(including complex) are
converted to integer when the subscript is evaluated.

l\ subscript may contain
function references
(Chapter 14).
For example: TABLE (SIN (A) *B,2,3) is a valid array element
identifier.

Subscripts may contain array element identifiers nested to
any level as subscripts.
For example,
in the subscript
(I(J(K(L») ,A+B,C) the first subscript quantity given is a
nested 3-level subscript.

Here are examples of valid array element subscripts:
1.

IAB(1,5,3)

ABLE (.1\)

TABLEl(lO/C+K**2,A,B)

MAT(A,AB(2*L), .3*TAB(A,M+l,D) ,55)

3-8

DATA TYPES, CONSTANTS, SYMBOLIC NAMES,
3.5.2

V~RIABLES,

~ND

ARRAYS

Dimensioning Arrays

You must declare the size (number of elements) of an array in order to
enable FORTRAN-IO to reserve the needed amount of locations in which
to store the array. Arrays are stored as a series of sequential
storage locations. Arrays, however, are visualized and referenced as
if they were single or multi-dimensional rectilinear
matrices,
dimensioned on a row, column, and plane basis.
For example, the
following figure represents a 3-row, 3-column, 2-plane array. -

3 ROWS

...
~
/'
~

_ _ _ - - y - ______

--------.I

,<--co,

~'v

3 COLUMNS

You specify the size of an array by an array declarator written as a
subscripted array name.
In an array declarator, however, each
subscript quantity is a dimension of the array and must be either an
integer variable or an integer constant.
For example,
declarators.

TABLE(I,J,K)

and

MATRIX

(10,7,3,4)

arc

valid

array

The total number of elements that comprise an array is the product of
the dimension quantities given in its array declarator.
For example,
the array lAB dimensioned as lAB (2,3,4) has 24 elements (2 X 3 X 4
24) .
You use dimension arrays only in the specification
statements
DIlVlENSION, COMMON, and type declaration
(Chapter 6).
E,ubscripted
array names appearing in any of the foregoing statements are array
declarators;
subscripted
array
names appearing in any other
statements are always array element identifiers.
In array declarators
the position of a given subscript quantity determines the oarticular
dimension of the array
(e.g.,
row,
column, or plane)
that it
represents. The first three subscript positions specify the number of
rows, columns,
and planes that comprise the named array;
each
following subscript given then specifies a set comprised of n-number
(value of the subscript) of the previously defined sets.
For example:

3-9

DAT~

TYPES, CONSTANTS, SYMBOLIC NAMES, VARIABLES, AND ARRAYS

The Dimension Declarator

Specifies the Array( s)

ITTI]

TAB (2)
TAB (2,2)

TAB (2,2,2)

TAB (2,2,2,2)

NOTE

FORTRAN-IO
permits
any
number
dimensions in an array declarator.
3.5.3

Order of 3tored Array Elements

The elements of an array are arranged in storage in ascending order.
The value of the first subscript quantity varies between its ~inimum
and maximum values most rapidly.
The value of the last given
subscript quantity increases to its maximum value least rapidly.
For
example, the elements of the array ~imensioned as 1(2,3) are stored in
the following order:
I (I, 1)

I ( 2, 1)

1(1,2)

(2,2)

(I, 3)

(2,3)

In the following list, the e12ments of the three-dimensional array
(0(3,3,3))
are stored row by row from left to right and from top to
bottom.
B (1,1,1)

B (2,1,1)

B(3,1,1)

--I

1---. B (I,2,1)

B(2,2,1)

B(3,2,1)

--I

C ~ B(!~3~) - - -B(£3:1) - - - B (3,3, I) -=- ~
---------------------

rhus B(3,1,1)

is stored before B(1,2,1), and so forth.

3-10

CHAPTER 4
EXPRESSIONS

4.1

ARITHMETIC EXPRESSIONS

Arithmetic expressions may be either siffiple or compound.
arithmetic expressions consist of an operand that may be:

Simple

a constant

a variable

an array element

a function reference (see Chapter 14 for descr ipt ion), or

an arithmetic
parentheses.

logical

expression

written

within

Operands may be of integer, real, double precision, complex, octal, or
literal ty~?e.
"

The following are valid examples of simple arithmetic expressions:
(integer constant)
(integer variable)
(array element)
(function reference)
(a parenthetical expression)

10 3
1

lAB
TAJ3LE(3,4,5)
SI!\] (X)
(A+B)

A compound arithmetic expression consists of two or more operands
combined by arithmetic operators.
Table 4-1 lists the arithmetic
operations permitted in FORTRAN-IO and
the operator
recognized for
each.
Table 4-1
Arithmetic Operations and Operators
Operation
1. Exponentiation
:2 • Multiplication
:3 • Division

4. Addition
1-

. Subtraction

Operator

Exai11ple

** or
*

A**B or A"B
A*B

AlB
.l\+B
A-B

4-1

EXPRES3IONS
Rules for Writing Arithmetic Expressions

4.1.1

Observe the
e x pre s s ion~; :
1.

following

rules

structuring

compound

arithmetic

The operands comprising a com90und arithmetic expression may
be of different types. Table 4-2 illustrates all ?ermitted
cOillbinations of data types and the type assi0ned to the
result of each.
NOTE
Only one combination of data types, double-precision
with complex, is prohibited in FORTRAN-IO.

An expression cannot contain
operators.
For
example,
permitted.

All operators must be included;
no operation is implied.
For
example,
the
expression
A(B)
does not specify
multiplication although this is implied in standard aljebraic
notation.
The expression A*
(8)
is required to obtain a
multiplication of the elements.

When you use exponentiation,
the base quantity and its
exponent ~ay be of different types.
For example,
the
expression ABC** 13 involves a real base and an integer
exponent.
The permitted base/exponent type combinations and
the type of the result of each combination are given in Table
4-3.

4-2

two adjacent and unseparated
the expression A*/B is not

Table 4-2
Type of the Result Obtained From Mixed Mode Operations
-----0---------- ------------y------------- - - - - - - - - - - , - - - - - - - - -

---------

Double
Precision

Real

---------

---

I y ~ 't' \ II ! !Ill.'! a (\1' n

( OIllPIl'X

- - --- -- --1-------------

--------------

I Douhk Precision

I Rl'al

_. Douhle Precnilon
-\

(ODVCI."HHI llll

Integer

.\ r~lJ!Ilt"llt

I:rorll Intl't~er til

J J;rom hHf!ger 10

Real

Octal

(omrk ...

Inh'!!l'r

'\Jont.'

",",Hit'

\lone

4. ~()Ilt.'

Double ().:tal

Literal

-------I IntegcI

('oHlpkx

Double Precision

Integer

I:rom Inh'gcr to
COPlpk;\. Valul'

None

U'l'U <I" RCr..Il p.lrt
4

0Jonc

~Ollr,.'

1 High orLier word

\n'L1IlI~'llt .'

IIlgh ord or word
is used directly;
further words
are ignored

Real

L'i lIsc:J ulredly
loVv order \I,'ord

----- -

---- --- -------

is ignored

--------I

Ic-_.I

DOllblt' Pre(lsion

f{t'J.1

COlllpll'\
( tUlIP!c'

Kc ..d

Real

wltn fl'\U!!

Real

\rYUllIL'1l1

Used directly ,IS
thl' hlgh order
word, low orLi t'r
word is ZE.'TO

(IH1Vl'r\!,'1l 'HI

I rom In(cgl..'r to

IISe-d dlll'llly ;1\

Nom'

lIigh ord", word

p:ut

lIilJ~In"ry

\lom~

'\JOlll'

\10m'

Rl'al

\rV,lIIlH.'nt "

Ihe Redl part.

High onler word
IS Uit.·J dirt.·I. :tly,

is used directly,
further words
are ignored

low ordu word
i.;;; i!!nort!d

---I ypt: 01 'JPt'IJIIIJTl

~-----------

-+---------i---- -------- - - - f - - - - - - - - - - - - --------- ----r---.----------I---------- 1---------,

Douhk Prcl..'lsl011

Ilouhle Prenslon

I I'Hlhlt' PTl'L"I...I'lrl

()olJhk

PrrCl.",ioll

Douhl!! I·re .:ision

Doublt: Prc:i'iIOI1

~df1l'

Double Precision
Double Prl't..'i')ion

:'\Oll\.'

\ r ~ ~ tI ! Ill' Il [ I
'l

(OI\Vt'r"'J(HI ( l [ j

\n'Ujlll'T1T -'

I rorll In{l'~t.'r to

-t l\t'd dtrt' . :tly .1"

i)pubk Prt'l'isJOll

till' high uakr
\...·ord .Inw nnjr,.'r

t hl' tllgh vrdt'r

ttw IHgh 'JrJl'f

\I,ord.lo\l. onkr

w(lrd, 10'" (lrJ\.'r

furth~r words

",on..! 1~ lero.

word. I'> It'rl,)

word 1\ lero

arc ignored.

---------------

f----------I

I YI'l' ,It :1,l\•.'r,ltHHl

("('mpk:...

-l

{ll!1!pk\

(dl!l:lil \

( olllpk . .

('ulIlpl('\

<-1

li"'l'd din (fly ,1<;

1 Fir . . t two words
art' useJ Jiret.:t1y:

f-----------------'--t---------------,-----------------

-------- - - - - - - - - - - - -

l:\l'd ~lJn'I..'tly :.to,

('orllplcx

I ('umpll'x

(·Ol1lpll'.1(

I Comple.
Complex

('omrll'x

\~ II h rl'~ldl

(nnVcrSlnTl 1111

(lIIlVI..'r..,IIIII\111

Complex

\n.'LJlIll'lll

3 \Junl'

\lout'"

J None

I
"

I r!)m Intq!.l"r h)

l;scd (lirl',,:tly ,I . .

IIo.;ed llirl'dly ,JS

·1

U"l"d dlIt'dly ;J~

the R(";.t1 p.lrI.

th!..: R.l'otl part,

Ib,- R,-al pdrt

lIsl·d J'i Rt.'dl P;H!

IIllJj:UI1;.tTY

p;ut

IlIlat-inary pJfl

lrJI.Jgjnar:; p.Hl

-------------------------t-----------

r---------- - - ----

-l

\" 11 II

('Plllpll'\ V;liLJe

In!l.'~.n

IhHloh.' Prl'cision

i'!(ITIC

l"l'J Jiu'..:{/y a,I)

----+_

--------1--------- - , - - - - - I

I n Il'~'l'r

Inll'ger

I Integer

NOlll'

J None

High ordl!r wnn.l
i . . u~l'd thrl't.'tly.
low order wort.!

Octal

I Yf't' J"",I'~ 1.1 r ,'11

l (lH\t'!"!111l

\rflJllll'Ol

'1\

First two words
are used directly_
"urther words
an' ignored.

.3 ll<,t"d threetl\' J'\

thl' tll~h ordn

thl..' gl'a! p.Ht

wurJ . low nrd t'r

InIJf,In,H\ PH!

~OIH'

,""ord IS 7.rro
~
\rl'Ujlll'I:!

'nnt'

,~.

~Olll'

4 l\iom'

4. \JUIlI"

-'l

l'i IE!JhJrl.'d

----4-----------------------------------~-----------------I IIHl'gCI
I DOllbk PrccJ'iloll
I R""I

Intq'.l"f

Intq!l'r

I ypt' i.I'i~()\.·IJIt'd

Intq.!;l'T

lIigh order word
is u,,-d directly;
further wnrds
art' ignored

I Integer
Odal

(kt,d

With U',lIlt

('onvl'rslon ( I n

Oclal

('()T1Vl'r~IUIl U!l

l'Sl'd dllc..:t1, d ....

lL";l'd dIrvdl\. .1'>

the high l)fJ,'r

[he Keai pJrt

\\ ord. low ordcr
\I. ord I~ Icro

1I1!;lf..Hl;]r~

3 None

P,lrf

-1

'mil'

High onil'r ,\-oru

I~ u<;\.'J dlTl'dly

,\rpUllt'lll "

low onh,r \l,ord
10.; igil'. )rt'd

I ypc of l)pcuhon

Real

(olllpll· ...

Inrq!l"r

Inleger

1_ Integer

High order """rd
is u.s.ed ducctty;
further words
arc ignored

I Integer

used
....

I YIH' JS.~OCldlt:d

Rt'J:1

__ OrtJI

Double Prl'"cision

(ktal

Octal

with result

Double
Oclal

Argi.1ll1l'llt I

4 ('onvcrl\lOn on

J _ II igh ord a -.'ord

J II igh unkr \I, ord
i~ Ll~l'(.l dirl'dlv

is U~l:U dircf.:tly.

l,) ust:'d diJedly

1';

loy.. ordl'r wurd

io\\'" on..lcr word

10\,1,' orda word

low ortJcl word

low order ,""oro

!P\.\ (\!liL'r \\rLlId ...

is i~nl)red

I~ ignored

b ignored.
lIigh orda word
is used dirl.'dly.
low order \\ord

H,,' 1I'.llolcd

4 :'\'unt:

None

. .1-.

NOll\.'

Non\.'

1 llirh ord." word

4 :--JOlll'

Argumrnt 2

I. I Yilt.' of Dpt:'r,ltIOn

Douhlc Pret:isi< 'n

with tl'suit
3. Conversinn on
Argun1f'nl I

High ordt.'r word
is used diH'ctly,

Argument ::

.3 First {wo word>;

None

3 First fwo \I.·ords

f"urtht.'r words
None

further W0H.b

~om'

t I ij!h orda 'Word

Integer

__ (lctal

;

3 lIigh order Nord
is us cd din:cUy.

High ordl'f word

is U~l'J dift~dly.
furtht'r words

furtht'r words

further word'i
arc ignor,;,:d

JT\.' IglllHl'd

'onl'

Inkger

__ ll,-tal

l'i used diredly

aTl' i~noTt.'d

are ignored.
...\

art' used (hrt·~tly.

arc used dired!y:

lurthn words
Jrc ignoTt'd

furtheT wordli
~onc

I Hgh unll'r word
i~ lJs('d lliredly:

Jrc ignored
('onvC"r~i~)Jl Of]

I COlllpie:\

Rrai

i") pl' .lss(~l."i,jh.'J

~OJh'

IlIgh ord'>!r word
{;..; lI~CJ directly,

low ord cr y. oru

b iglwred
L -_______________________________________ ~ _____________~______________~~ _____________~--------------~---------------~----------------

lI~t'd JIIL'lfl~ :

I hgh' lll"J(,f wnld
i.., 1I,..:J dlr('\.'!!)

loVv p[liL'r WlHth
rt' 1~IHHI..'d

L\ ignor~d.

--- --- ----1----------- f------ -------I--------+-------+--------+------------t--.--'--'-

literal

,Ii~h (llJC! WL'II.1

J lIigh ordt.'J word
is USl't! dirn.:tly,

3 lli!!h (lrder word
is lIsed dITt.'dly,

Integer
Octal

iligh order word
is used directly;
further words
are ignored_
4 lIigh order word
is used directly;
further words
ar~ ignort'd

EXPRESSIONS
I'able 4-3
Permitted Base/Exponent Type Combinations
I

Base Operand

Integer
Real
Double
Precision
Complex

4.2

Exponent Operand
[Integer

;Real

Integer

Real

Double
Precision

Double
Precision
Real
Real
Double
Precision
Double
Double
Double
Precision Precision Precision
(Undefined)
Complex
Comi?lex

Complex

Comolex
Complex

Complex

LOGICAL EXPRESSIONS

LOJical expressions may be either simple or compound. Simple logical
expressions consist of a logical operand, which may be a logical type:
1.

constant

variable

array element

function reference (see Chapter 15), or

another expression written within parentheses.

Compound logical expressions consist of two or more oDeran0s
by logical operators.
Table 4-4 gives the logical operators permitted by
description of the operation each provides.

FORTRAN-IO

combined
and

EXPRESSIONS
Table 4-4
Logical Operators
Operator

Description
operator. Both of the logical operands combined
this operator must be true to produce a true result .

.l\ND.

AND

. OR.

Inclusive OR operator.
If either or both of the logical
operands combined by .OR.
are true, the result will be
true.

. XOR.

Exclusive OR operator.
If either but not both of the
logical operands combined by .XOR.
is true, the result
will be true.

.EQV.

Equivalence operator.
If the logical operands being
combined by .EQV.
are both the same (both are true or
both are false) I the result will be true.

.NOT.

Complementation operator. This operator
is us?d as a
prefix that specifies complementation (inversion) of the
item (operand or expression)
that it modifies.
The
original item, if true by itself, becomes false, and vice
versa.

Write logical expressions in the general form P .oP. Q, where P and·
Q are logical operand and .oP.
is any logical operator but "."JOT.".
The .NOT. operator complements the value of a logical operand;
you
~ust
write it immediately before the operand that it modifies, e.g.,
.NOT.P. Table 4-5 is a truth table illustrating all possible logical
combinations of two logical operands (P and Q) and the resultant of
each combination.
When an operand of a logical expression is double-precision or
complex, only the high-order word of the operand is used in the
specified logical operation.
The assignment of a .TRUE. or a .FALSE. value to a given operand is
based only on the sign of the numeric representation of the operand.

4-5

EXPRESSIONS
Table? 4-5
Logical Operations, Truth Table
When P is

And

------

is:

The?n the? Expression:

------------ -----------------

Is:

- ._----

True

.NOT.P

False?

False

.NOT.P

True

.Al~D.

True

False

P .AND.

False

True

.A~D.

False

P .AND.

False

True

TrUe?

True

False

P .OR. Q

TrU2

False

True

.OR.

True

False

P .OR.

False

True

P .XOR. Q

False

True

False

P .XOR. Q

True

False

True

.XOR. Q

True

False

P .XOR.

True

P .EQV. Q

True

False

P .EQV.

False

True

P. EQV. Q

r"'alse

False

P .EQV. Q

True

.OR.

False

Examples
Assume the following variables:
Variable?
RE}\L, RUN
I,J,K
DP,D
L, A, B
CPX,C
Examples of valid logical
variables are:

Type
Re?al
Integer
Double Precision
Logical
Complex
expressions

L.AND.i3
(REAL*I) .XOR. (DP+K)
L.AND.A.OR .. NOT. (I-K)
4-6

consisting

the

fore]oing

EXPRESSIONS
Logical functions are per Eorined on the full
36-bi t
binary processor
representation of the operands involved.
The result of a logical
operation
is
found
by
oerforming
the
specified
function,
s i In u 1 tan e 0 u sly ,
for e a c h 0 f the cor res po n din 9 bit s i!1 e a c hOD era n d •
for example, consider the expression A=C.OR.D, where C="456 and
D='120l. The operation performed by the processor and the result is:
;rJord
Bits
Operand C
Of?erand 0
Result t\

0
0
0
0

• 24
• 0
• 0

1
0
0

•

25 26

a a

27
1

0
0

0
1
1

0
0
0

30
1

31
0
0
0

32
1

1
0

34 35
1 0
0
1
1 1

Table 4-S also illustrates all possible logical combinations of two
one-bit binary operands
(P and Q)
and gives the result of each
combination. Just read 1 for true and 0 for false.

4.2.1

Relational Expressions

Relational ex?ressions consist of two expressions combined by a
relational operator.
The relational operator permits the programmer
to test, quantitatively,
the relationship between two arithmetic
expressions.
The result of a relational expression is always a
false value.

logically

true

In FORTRAN-IO, you ~ay write relational operators either as a 2-letter
mnemonic enclosed within periods, e.g., .GT., or symbolically using
the symbols, >, <, = and #. Table 4-6 lists both the mnemonic and
symbolic forms of the FORTRAN-IO relational operators and specifies
the type of quantitative test perfor~ed by each operator.
Table 4-6
Relational Operators and Operations
Relation Tested

Operators
----y------_.- ---------

Mnemonic

Symbolic

- - - - - - - + - - - - - - - - - --oi--

.GT.
.GE.
.LT.
.LE.
.EQ.
.NE.

>
>=
<
<=

Greater than
Greater than or equal to
Less than
Less than or equal to
Equal to
Not equal to

4-7

EXPRESSIONS
Write relational expressions in the general form A(l) .OP.A(2), where
A represents an arithmetic operand and .OP.
is a relational operator.
You may mix arithmetic operands of type
precision in r21ational expressions.

integer,

real,

and

double

You may com?are complex operands using only the operators .EQ. (==) and
.~E.
(#).
Complex quantities are equal if the corresponding ?arts of
both words are equal.
Examples
Assume the following variables:
-va ria b 1 e s
RE.l'tL, RON
I,J,K
DP,D
L,A,B
CPX,C

Type
Real
Integer
Double Precision
Logical
Complex

Examples of valid relational expressions consisting of
variables are:

the

foregoing

(REAL) .GT.IO
I == 5
C.EQ.CPX
Examples of invalid relational expressions consisting of the foregoing
variables are:
(REAL) .GT 10 (closing period missing from operator)
C>CPX

combined

.EQ.

Examples of valid expressions that use both logical
operators to combine the foregoing variables are:

and

relational

(complex operands can only be
.NE.
operators)

( I • GT. 10). AN D. (J <= K)
(( I*RON) == (I/J» .OR. K
(I. AND. K) # ( (REAL) . OR. (RON) )
C#CPX.OR.RON

4-8

and

EXPRESSIONS
4.3

EVALUATION OF EXPRESSIONS

The following determine the
expression:

order

computation

the use of parentheses

an established hierarchy for
the execution
relational, and logical operations and

the location of operators within an expression.

4.3.1

Pa~enthetical

FORTRA~-lO

arithmetic,

Subexpressions
---------

In an expression, all subexpressions written within parentheses are
evaluated first.
When parenthetical subexpressions are nested (one
contained within another) the most deeply nested subexpression is
evaluated
first,
the next most deeply nested subexpression is
evaluated second, and so on, until the value
of
the
final
parenthetical expression is computed. When more than one operator is
contained by a parenthetical subexpression, the required computations
are performed according to the hierarchy assigned operators by
FO~rRAN-la (Section 4.3.2).
Example:
The separate computations performed in evaluating the expression
A+B/((A/B)+C)-C are:

.
'

Rl=A/B

2=Rl+C

R3=B/R2

R4=R3-C

R5=A+R4

WHERE:

4.3. 2

Rl THROUGH R5 REPRESENT THE INTERIM AND FINAL RESULTS
COMPUTATIONS PERFORMED.

HiE~rarchy

THE

the

of Operators

The following hierarchy
(order of
classes of FORTRAN-IO operators:

execution)

arithmetic operators,
first,
second, relational operators, and
third, logical operators.

4-9

assigned

EXPRESSIONS
Table 4-7 specifies the precedence
operators of the foregoing classes.

assigned

individual

the

With the exception of integer division and exponentiation, all
operations on expressions or subexpressions involving operators of
equal precedence are computed in any order that is algebraically
correct.
A sUbexpression of a given expression may be computed in any order.
For example,
in the expression (F(X) + A*B), the function reference
may be computed either before or after A*B.
Table 4-7
Hierarchy of FORTRAN-IO Operators
-- ---_ ... _ . _ - - - - - - - - - - _ . _ -

,-------------- - - - - - - - - - - -

Class

Level

EXPONENTIAL First
r------------- r - . -..- - - - - . Second
Third
ARITHMETIC
Fourth

._-----_ ...

... _ - - - - - - ,

Symbol or Mnemonic
**
- (unary minus) and + (unary plus}
*,/
+,-

t - - - - - - - . - - - - - f - - - - - - -.. ---- ..

RELATIONAL

Fifth

.GT.,.GE.,.LT.,.LE.,.EQ.,.NE.
or

>,>=,<,<=,==,#
f - - - - - - - - - - - - . - -.--... -----.. - .. -.-- --.- ---.. -.------ --_ ...- - - - . - . - - - . - - - - - . - - - - - - - - - .... ----.-..---- - - - -

LOGICAL

Sixth
Seventh
Eighth
Ninth

.NOT.
.AND.
.OR.
. EQV . , . XOR.

' - -_ _ _ _ _ _ _ _L---_ _ _ _ _--L_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _- - '

Operations specifying integer division are evaluated from left to
right.
For example, the expression I/J*K is evaluated as if it had
been written as (I/J)*K. But this left-to-right evaluation process
can be overridden by parentheses.
I/J*K(evaluated as(I/J) ,rK) :]oes
not equal 1/ (J*K) ,which is evaluated as written here.
When a series of exponentiation operations occurs in an expres~;ion, it
is evaluated in order from right to left.
For exa~ple, the expression
A**2**B is evaluated in the following order:
first Rl = 2**B (intermediate result)
second R2 = A**Rl (final result).
Similarly, here too, parentheses alter the evaluation
expression. (A**2)**B is evaluated in these two steps:
first Rl = A**2 (intermediate result)
second R2 = Rl**2 (final result)

4.3.3

the

Mixed Mode Expressions

Mixed
mode
expressions
are
evaluated
on
a
subexpression-by-subexpression basis, with the type of the results
obtained converted and combined with other results or terms according
to the conversion procedures described in Table 4-2.

4-10

EXPRESSIONS
Example
Assume the following:
Variable
D
X
I,J

Type
Double-Precision
Real
Integer

The mixed mode expression D+X*(I/J)
manner:
1.Rl

I/J

2.R2 =X*Rl
3.R3

D+R2

evaluated

the

following

Rl is integer
Rl is converted to type real and is multiplied
to produce R2

R2 is converted to type double precision and is added
to D to produce R3

where

Rl and R2, and R3 represent the interim and
respectively of the computations performed.

4.3.4

Use of Logical Operands in Mixed Mode Expressions

final

results

When you use logical operands in mixed mode expressions, the value
the logical operand is not converted in any way to accommodate it
the type of the other operands in the expression.
For example,
L*R, where L is type logical and R is type real, the expression
evaluated without converting L to type real •

.
'

4-·11

of
to
in
is

CHAPTER 5
COMPILATION CONTROL STATEMENTS

5.1

INTRODUCTION

You use compilation control statements to identify FORTRAN-IO programs
and to specify their termination.
Statements of this type do not
affect either the operations performed by the object program or the
manner in which the object program is executed. The three compilation
control statements described in this chapter are: PROGRAM statement,
INCLuDE !3tatement, and END sta tement.

5.2

PROGRAM STATEMENT
~·t

This st~tement allows you to give the main program a name other than
the co~piler-assumed name IIMAIN.
The general form of a PROGRAM
statement is: ,
II

PROGRAM

n~me

where:
name

is a symbolic name that begins with an alphabetic
character and contains a maximum of six characters.
(Refer to Section 3.3 for a description of symbolic
names. )

The following rule governs the use of the PROGRAM statement:
The PROGRAM statement must be the first statement in a program
unit.
(Refer to Section 2.4 for a discussion of the ordering of
FOR~RAN-lO statements.)

5.3

INCLUDE STATEMENT

This statement allows you to include code segments or predefined
declarations in a program unit without having them reside in the same
physical file as the primary program unit. The general form of the
INCLUDE statement is
INCLUDE 'dev:filename.ext[proj,prog]/NOLIST'
where:
dev:

is a device name.
When no
specified, DSK:
is assumed.

5-1

device

name

COMPILATION CONTROL

ST~TEMENTS

is the filena~e and extension of the FORTRAN-IO
statements that you wish to include. The name of
the file is required;
the extension is optional.
If you specify "filename" only,
.FOR is the
assumed extension.
If you specify the filename
and period
(filename.),
the null exten~;ion is
assumed.
You
Qay
not
specify
wild
(*)
in for lTI a t ion.
[proj,pro<]]

is the project-programmer number.
Your 9[ojectprogrammer nu~ber is assumed if none is specified.
You cannot specify subdirectory information.

/NOLIST

is an optional switch indicating that the included
statements
are
not
to be included in the
compilation listing.

The following rules govern the usc of the INCLUDE statement:
1.

The INCLUDEd file may contain any legal FORTRAN-IO statement
except
another
INCLUDE statement, or a statement that
terminates the current program unit,
such as the END,
PROGRAM, FUNCTION, SUBROUTINE, or BLOCK DATA statements.

The proper placement of the INCLUDE statement within a
program unit depends upon the types of statements to be
INCLUDEd.
(Refer to Section 2.4 for
information on the
ordering of FORTRAN-IO statements.)

The file(s)

to be

Note that an asterisk (*)
INCLUDEd statements on
not specified.

5.4

I~CLUDEd

must be on disk.

is appended to the line numbers of the
the compilation listing, provided /NOLIST is

END STATEMENT

Use this statement to signal FORTRAN-IO that the physical end of a
source program or subprogram has been reached.
END is a nonexecutable
statement. The general form of an END statement is:
END
The following rules govern the use of the END statement:
1.

This statement must be the last
source program or subprogram.

When used in a main program, the END statement implies a STOP
statement operation;
in a subprogram, END implies a RETURN
statement operation.

You

~ay

label an END statement.

5-2

physical

statement

CHAPTEH. 6
SPECIFICATION STATEMENTS

6.1

INTRODUCTION

Use specification statements to specify the type characteristics,
storage allocations, and data arrangement. There are seven ty~es of
specification statements:

DIMENSION

Statements that (::?xplicitly
INTEGER

IMPLICI'r

COM.MON

EQUIVALENCE

EXTERNAL

7•

PARAMETEH

~3pecify

type,

such

REAL

Specification statements are nonexecutable and conform to the ordering
guidelines described in Section 2.4.

6.2

DIMENSION STATEMENT

DIMENSION statements provide FORTRAN-IO with infor~ation needej to
identify and allocate the space required for source program arrays.
You may specify any number of subscripted array names as array
declarators in a DIMENSION statement. The general form of a DIMENSION
statement is
DIMENSION Sl, S2, ... ,Sn
where Si is an array declarator.
following form:
name (max, ... , max)

Array declarators are names

the

name(min:max, ••• ,min:max)

where name is the symbolic name of the array, and each min:max
represents the lower and upper bounds of an array dimension.

6-1

value

SPEClrIC~TION

STATEMENTS

Each min:max value for an array di~ension may be either an integer
constant
or,
if the array is a dummy arjument to a
subprograio, an integer variable.
The value given the
minimum
specification for a dimension must not exceed the value given the
~aximum specification.
Minimum values of 1 with their following colon
deli~iters may be omitted from 3 dimension subscript.
This is because
~inimum values are assumed to be 1 in the first place.
Exarnples
DIYIEl'JSION EJGE (-1:1,4:8), NET (5,10,4), TABLE (567)
DIMENSION TABLE (IAB:J,K,M,lO:20)
( wher e I r\ 3, .J,

and

are oft Y p e i i1 t e g e r) .

Note that you may use a slash in 91ace of a colon as the
between the upper and lower bounds of an array dimension.

6.2.1

delimiter

Adjustable Dimensions

~J hen

use d wit h ina sub pro g ram, a n a r ray dec 1 a rat arm a y use t y p e
integer parameters as dimension subscript quantities. The following
rules govern the use of adjustable dimensions in a subprogram:
1.

For single entry subprograms, the array name and each
subscript variable must be given by the calling program as
parameters when the subprogram is called.
The subscript
variables may also be in COMMON.

For multiple entry subprograms in which the array name is a
parameter, any subscri?t variables may be passed.
If all
subscript variables are not passed or in COMMON, the value of
the subscript as passed for a previous entry will be used.

The type of the array dimension variables cannot
within the program.

If the value of an array dimension variable is altered within
the program, the di~ensionality of the array will not be
affected.

The original size of the array cannot exceed the array
dimensions assigned within a subprogram, i.e., the size of an
array is not dynamically expandable.

Examples

SUBROUTI~E SBR (ARRAY,Ml,M2,M3,M4)
DIMENSION ARRAY (Ml:M2,M3:M4)
DO 27 L=f13,M4
DO 27 K=Ml,M2
ARRAY (K,L)=VALUE
CONTINUE
Er~D

SUBROUTINE SBI (ARRI,M,N)
DIMENSION ARRI(M,N)
ARRI (M,"N) =VALUE
ENTRY SB2(ARRl,M)
ENTRY SB3(ARRl,N)
ENTRY SB4 (ARRI)
5-2

altered

SPECIFICATION STATEMENTS
In the foregoing example, the first call made to the subroutine must
be made to 581. Assuming that the call is made at SBI with the values
M=ll and N=13, any succeeding call to 5B2 should give M a new value.
If a succeeding call is made to 5B4, the last values passed through
entries SRI, 582, or 5B3 will be used for M and N.
Note that for the calling program of the form:
CALL 5Bl(A,11,13)
M=15
CALL 5B3 (A, 13)
the value of M used in the dimensionality of the
execution of S83 will oe 11 (the last value passed).

6.3

array

for

the

Type SPECIFICATION STATEMENTS

Type specification statements declare explicitly the data type of
variable,
array, or function symbolic names. You may give an array
name in a type statement either alone (unsubscripted) to declare the
type of all its elements or in a subscripted form to specify both its
type and dimensions.
Write type specification statements in the following form:
type list
where type may be anyone of the following declarators:
I •

1l'J 'r E G E R

REAL

DOUBLE PRECISION

COMPLEX

LOGICAL

NOTE
In order to be compatible with the type
statements used by other manufacturers,
the data type size modifier, *n,
is
accepted by FORTRAN-ID. You may append
this size modifier to the declarators,
causing some to elicit messages warning
users of the form of the
variable
specified by FORTRAN-ID:

6-3

SPECIFICATION STATEMENTS
I)eclarator
I.'J'I'EGER*2
r0JTEGER*4
LOGICAL*1
LOGICAL*4
REAL*4
REAL*8
COl\lPLEX* 8
COMPLEX*16

Form of Variable Specified
Full
Full
Full
Full
Full

word integer with warning message
word integer
word logical with warning messa1e
wrd logical
word real
Double-~recision real
Cornplex
Complex with warning message

In addition, you may append the data
type
size
modifier
to
i~dividual
variables, arrays,
or
function names.
Its effect is to override,
for
the
particular element,
the size modifier
(explicit or
implicit)
of the 9rimary
type.
For example,
REAL * 4 1\, B* 8, C* 8 ( I 0), D
A and D are single-precision
(one full
word)
real,
and
Band
Care
double-precision (two full words) real.
The list consists of any number of variable, array, or function names
that are to be declared the specified type.
The na~es listed must be
separated by commas and can appear in only one type statement within a
program unit.
Examples
INTEGER A, B, TABLE, FUNC
REAL R, M, ARRAY (5:10,10:20,5)
NOTE
Variables, 3rrays, and functions of a
source program, which are not typed
either implicitly or explicitly by a
specification statement,
are ty?ed by
FORTRAN-IO accorrling to the
followi~g
conventions:
1.

Variable names,
array names,
and
function names that begin with the
letters I, J, K, L, M, or N are type
integer.

Variable names,
array names,
and
function names that begin with any
letter other than I, J, K, L, M,
or
N are type real.

If a name that is the same as a predefined FORTRAN-IO function name
appears in a conflicting type statement, it is assumed that the name
refers to a user-defined routine of the given type.
If you place a
generic predefined FORTRA~-lO function name in an explicit tyoe
statement, it loses its generic properties.

6-4

SPECIFICATION STATEMENTS
6.4

IMPLICIT STATEMENTS

functions
IMPLICIT statements declare the data type of variables and
according
to
the
first
letter of
each variable name.
IMPLICIT
statements are written in the following form:
IMPLICIT type

(Al,A2, •.• ,An), type (Bl,B2, ..• ,Bn) , ... ,type . . . . .

As shown in the
foregoing
form statement,
an
IMPLICIT statement
consists of one or more type declarators separated by commas.
Each
type declarator has the form
type

(Al,A2, •.. ,An)

where type represents one of the declarators listed
in Section 6.3,
and the parenthetical list represents a list of different letters.
Each letter in a type declarator
list specifies that each source
program variable
(not declared
in
an explicit type soecification
statement) starting with that letter is assigned the data
type
named
in the declarator.
For
example, the IMPLICIT type declarator REAL
(R,M,N,O) declares that all names that begin with the letters R, M, N,
or 0
are
type REAL names, unless declared otherwise in an explicit
type statement.
NOTE
Type declarations given in an explicit
type specification override those also
given
in
an
IMPLICIT
statement.
IMPLICIT declarations do not affect the
FORTRAN-IO supplied functions.
You may specify a range of letters within the alphabet by writing
the
first and last letters of the desired range separated by a dash, e.g.,
A-E for
A,B,C,D,E.
For
example,
the
statement
IMPLICIT INTEGER
(I,L-P)
declares
that all variables which begin with the letters
I,L,M,N,O, and P are INTEGER variables.
You may use more than one IMPLICIT statement,
but they must appear
before any other declaration statement in the program unit.
Refer to
Section 2.4 for a discussion on orderinJ ?ORTRAN-IO statements.

6.5

C~MMO~

STATEMENT

The COMMON statement enables you to establish
stor~Je
that may be
shared by two or more
programs and/or subprograms and to name the
variables and arrays that are to occupy the common storage.
The use
of common storage conserves storage and provides a means to implicitly
transfer arguments between a calling program and a subprogram.
write
COMMON statements in the following form:
COMMON/Al/Vl,V2, ... ,Vn ... /An/Vl,V2, ... ,Vn
where the enclosed letters /AI/, ... ,
/An/
represent optional
constructs (referred to as common block names when used) .

name

'3 ~ SC If 1 CAT I l)N ,;'1' /1.'C,"': ~'lENTS

The list (e.g., Vl,V2 ... ,Vn) appearing after each name construct lists
the names of the variables and arrays that are to occupy the common
area identified by the construct. The items specified for a common
area are ordered within the storage area as they are list~d in the
COMMON statement.
Either label COMMON storage areas or leave them blank (unlabeled).
If
the common area is to be labeled, qive a symbolic name within slashes
immediately before the list of items that is to occupy the nanles area.
For example, the statement
COMMON/AREAI/A,B,C/AREA2/TAB(13,3,3)
establishes two labeled com~on areas (i.e., AREAl and AREA2).
Common
block names bear no relation to internal variables or arrays that have
the same name.
If a common area is to be declared as unlabeled, give either nothing
or two sequential slashes (//) immediately before the list of items
that is to occupy blank common.
For example, the statement
COMMON/AREAI/A,B,C//TAB(3,3,3)
establishes one labeled
(AREAl)
and one unlabeled
Unlabeled common area is also called "blank common".

common

area.

A given labeled common name may appear more than once in the same
COMMON statement and in more than one COMMON statement within the same
program or subprogram.
Each labeled common area is treated as a separate, specific storage
area.
The contents of a common area, i.e., variables and arrays, may
be assigned initial values by DATA statements in
BLOCK
DATA
subprograms.
Declarations of a ~iven common area in different
subprograms must contain the same number, size, and order of variables
and arrays as the reference area.
Items to be placed in a blank common area may also be given
statements throughout the source program.

COMMON

During compilation of a source program, FORTRAN-IO will
string
together all items listed for each labeled common area and for blank
common areas in the order in which they appear in the source program
statements.
For example, the series of source program statem~nts:
COMMON/5TI/A,B,C/ST2/TAB(2,2)//C,O,E
COMMON/5TI/TST(3,4)//M,N
COMMON/3T2/X,Y,Z//O,P,Q
has the same effect as the single statement
COMMON/STI/A,B,C,TST(3,4)/ST2/TAB(2,2) ,X,y,Z//C,O,E,M,N,O,P,Q
All items specified for blank common are placed into one area.
Items
within blank common are ordered as they are given throu~hout the
source program. Common block names must be unique with respect to all
subroutine, function, and entry point names.
The

lar~est

definition of a given common area must be loaded first.

6-6

SPECIFICATION STATEMENTS
Dimensioning Arrays in COMMON Statements

6.5.1

Subscripted array names may be given in COMMON statements as array
dimension declarators. However, variables cannot be used as subscri?t
quantities in a declarator appearing in a COMMON statement~
variable
di~ensioning is not permitted in COMMON.
Each array name given in a COMMON statement must be dimensioned either
by the COMMON statement or by another dimensioning statement within
the program or subprogram that contains the COMMON statement but not
both.
Example
CO~1MON /A/B(lOO), C(lO,lO)
COMMON X (5,15) ,Y ( 5)

6.6

EQUIVALENCE STATEMENT

The EQUIVALENCE statement enables you to control the allocation of
shared storage within a program or subprogram. This statement causes
specific storage locations to be shared by two or more variables of
either the same or different types. Write the EQUIVALENCE statement
in the following form:
EQUI\/ALENCE(Vl,V2, ... ,Vn), (Wl,W2, ... ,Wn), (Xl,X2, ... ,Xn)
where each parenthetical list contains the names of variables
array elements that are to share the same storage locations.
example, the statements

and
For

EQUIVALENCE (A,B,C)
EQUIVALENCE (LOC,SHARE(I))
specify that the variables named A, S, and C are to share the same
storage location, and that the variable LaC and array element SHARE(I)
are to share the same location.
The relationship of equivalence is t[ansitive~
following statements have the same effect:

for example,

the

two

EQUIVALENCE (A,B), (B,C)
EQUIVALENCE (A,B,C)
have
~hen you use array elements in EQUIVALENCE statements, they must
either as many subscript quantities as dimensions of the array or only
the
one subscript quantity.
In either of the foregoing cases,
subscripts must be integer constants.
Note that the single case
treats the array as a one-dimensional array of the given type.
You may use the items given in
EQUIVALENCE
statement and in
following rules are observed:
1.

an EQUIVALENCE list in both
a COMMON statement providing

You cannot set two quantities declared in a COMMON
to be equivalent to one another.

6-7

the
the

statement

SPECIFICATION STATEMENTS
2.

Quantities placed in a common area by means of an EQUIVALENCE
statement are permitted to extend the end of the common area
forwards.
For example, the statements
COMMON/R/X,Y,Z
DIMENSION A(4)
EQUIVALENCE (A,Y)
cause the common block R to extend from Z to A(4)
follows:

arranged as

x
Y A(l)

Z A(2)

(shared location)
(shared location)

~(3)

A(4)
3.

You cannot use EQUIVALENCE statements that cause the start of
a common block to be extended backwards.
For examole, the
invalid sequence
COMMON/R/X,Y,Z
DIMENSION A(4)
EQUIVALENCE(X,A(3))
would require A(l) and A(2) to extend the starting location
of block R in a backwards direction as illustrated by the
following diagram:

~(l)

A(2)
X A(3)
Y A(4)

6.7

EXTERNAL STATEMENT

Any subprogram name to be used as an argument to another subprogram
must appear
in an EXTERNAL statement in the calling subprogram.
The
EXTERNAL statement declares names to be
subprogram
names
to
distinguish them from other variable or array names.
Write the
EXTERNAL statement in the following form:
EXTERNAL namel,name2, •.. ,namen
where each name listed is
desired, these subprogram

to be a sUbprogram name.
If
may be FORTRAN-IO defined functions.

declar~i

nam0~

You may also use FORTRAN-IO defined
function names
for
your
subprograms by prefixing the names by an asterisk (*) or an ampersand
(&) within an EXTERNAL statement.
For example,
EXTERNAL *SIN, &COS

6-8

SPECIFICATION STATEMENTS
declares SIN and COS to be user subprograms.
(If a prefixed nam~
not a FORTRAN-IO defined function, then the prefix is ignored.)

Note that specifying a predefined FORTRAN-IO function in an EXTERNAL
statement without a prefix, i.e., EXTERt~AL SIN, has no effect upon the
usage of the function name outside of actual argument lists.
If the
name has generic properties, they are retained outside of the actual
argument list.
(The name has no generic properties within an argument
list.)
The names declared in a program EXTERNAL statement are reserved
throughout the compilation of the program and cannot be used in any
other declarator statement, with the exception of a type statement.

6.8

PARAMETER STATEMENT

The PARAMETER statement allows you to
during compilation.

define

constants

symbolically

The general form of the PARAMETER Statement is as follows:
PARA.METER

Pl=Cl,P2=C2, ...

where
pi

is a standard user-defined identifier (referred to
section as a parameter name)

this

is any type of constant (including literals) except a label
or complex constant.
(Refer to Chapter 3 for a description
of FORTRAN-IO constants.)

During compilation, the parameter names are replaced by
their
associated constants, provided the following rules are observed:
1.

Place parameter names only within the statement field of an
initial or continuation line type, i.e., not within a comment
line or literal text.

Place parameter names only
acceptable.

Place parameter name references after the PARAMETER statement
definition.

Use parameter names that are unique with respect to all other
names in the program unit.

Do not redefine
statements.

Do not use parameter names as part of some larger syntactical
construct
(such as a Hollerith constant count or a data type
size modifier) •

parameter

6-9

where

names

FORTRAN-lO

constants

subsequent

are

PARAMETER

CHAPTER 7
DATA STJl.TEMENT

7.1

INTRODUCTION

DATA statements are used to sup~ly the initial
values of variables,
arrays,
array elements, and labeled common. (1) write DATA statements
as follows:
DATA Listl/Datal/,List2/Data2/, ... ,Listn/Datan/
where the List portion of each List/Data/ pair
identifies a
set of
items
to
be
initialized and the /Data/ portion contains the list of
values to be assign2d
the
items
in
the List.
For
example,
the
statement
DATA IA/5/,IB/IO/,IC/15/
initializes variable IA to the value 5, variable IB to the
value 10,
and
the variable IC to the value 15.
The number of storage locations
you specify in the list of variables must be less than or equal to the
n u ill be r
0 f
s tor age 10 cat ion s
you
s p e c i f yin its ass 0 cia ted 1 i s t 0 f
values.
If the list of variables is larger
(specifies more
storage
locations)
than
its associated value
list,
a warning message is
output.
When the value list specifies more storage locations than the
variable list, the excess values are ignored.

The List portion of each List/Data/ set may contain the names of one
or more variables,
array names,
array elements, or labeled common
variables.
You may specify an entire array (unsubscripted array name)
or
a
portion of an array in a DATA statement List as an implied DO
loop construct.
(See Paragraph 10.3.4.1 for a description of
implied
DO loops.) For example, the statement
DATA. (NARY(I) ,1=1,5)/1,2,3,4,5/
initializes the first
five
elements of array
NARY(2)=2, NARY(3)=3, NARY(4)=4, NARY(5)=5.

NARY

NARY(l)=l,

When you use an implied DO loop in a DATA statement,
the loop index
variable must be of type INTEGER and the loop Initial, Terminal, and
Increment parameters must also be of type
INTEGER.
In a
DATA
statement,
references to an array element must be integer expressions
in which all
terms are either
integer constants or
indices of
embracing
implied DO loops.
Integer
expressions of the foregoing
types cannot include the exponentiation operator.
The /Data/ portion of each List/Data/ set may contain one or more
numeric,
logical,
literal,
or
octal
constants and/or alphanumeric
strings.
1.

Refer

to Paragraph 6.5 for a description of labeled common.
7-1

DATA STATEMENT
You must identify octal constants by
quote (") symbol, e.g, "777.

preceding

them

with

double

You may specify literal data as either a Hollerith specification,
e.g.,
5HABCDE, or a string enclosed in single quotes, e.g., 'ABCDE'.
Each ASCII datum is stored left-justified and is padded with blanks up
to the right boundary of the variable being initialized.
~hen you assign the same value to more than one item in List, a repeat
specification may be used.
Write the repeat specification as N*D
where N is an integer that specifies how many times the value of item
D is to be used.
For example, a /Data/ specification of /3*20/
specifics that the value 20 is to be assigned to the first three items
named in the ~receding list. The statement

DATA M,N,L/3*20/
assigns the value 20 to the variables M, N, and L.
When the specified data type is not the same as that of the variable
to which it is assigned, FORTRAN-IO converts the datum to the type of
the variable. The type conversion is performed using the rules given
for
type conversion in arithmetic assignments.
(Refer to Chapter 8,
Table 8-1.)
Octal, logical, and literal constants are not converted.
Sample Statefilent
Use
first
DATA PRINT,I,O/'TEST ' ,30,"77/, (TAB(J) ,J=1,30)/30*5/ The
30
elements of array
TAB
are
initialized
to
5.0.
DATA( (A(I,J) ,1=1,5) ,J=1,6)/30*1.0/

No
conversion
required.

DATA( (A{I,J) ,1=5,10) ,J=6,15)/60*2.0/

No
conversion
required.

a literal string is specified that is longer than one variable
can hold, the string will be stored left-justified across as many
variables as are needed to hold it.
If necessary, the last variable
used will be padded with blanks up to its right boundary.

~hen

Exafilple
Assuming that X, Y, and Z are single-precision, the statement
DATA X,y,Z/'ABCDEFGHIJKL'/
will cause
X to be initialized to 'ABCDE '

Y to be initialized to 'FGHIJ '
Z to be initialized to 'KL~~~'
When a literal string is to be stored in double-precision and/or
com~lex
variables and the specified string is only one word long, the
second word of the variable is padded with blanks.

7-2

D!\Tz\ STATEMENT
Example
Assuming that the variable C is complex, the statement
OAT l\ C / I ABC 0 E I , I F Gil LJ I /
wi 11 c a u ~; e the fir s two r d 0 [ C to be i nit i ali zed t 8
I A Be 0 C I
un d
its
second
word
to be
initialized
to
1}6}6161616 1 . The string lFGHIJ 1 is
i~rno r ed •

...

CHAPTER 8
ASSIGNMENT STATEMENTS

8.1

INTRODUCTION

Use assignment statements to assign a specific value to
program variables.
There are three kinds of assignment

8.2

Arithmetic assignQent statements

Logical assignment statements

Statement Label assignment

(ASSIGN)

one

stateme~ts:

statements.

ARITHMETIC ASSIGNMENT STATEMENT

You use statements of this type to assign sgecific numeric
variables
and/or
array
elements.
write
arithmetic
statements in the form

values

assiqn~ent

v=e
where v is the name of the variable or
array element
that
is
to
receive
the
specified value and e is a simple or compound arithmetic
expression.
In assignment statements, the equal symbol (=) does not i~ply equality
as
it would
in algebraic expressions;
it implies replacement.
For
example, the expression v=e is correctly interpreted as
"the current
contents of
the
location
identified as v are to be replaced by the
final value of expression e;
the current contents of v are lost."
When the type of the specified variable or array element name differs
from
that of its assigned value, FORTRAN-IO converts the value to the
type of its assigned variable or array element.
Table 8-1 describes
the
type conversion operations performed by FORTRAN-IO
for each
possible combination of variable and value types.

8-1

Table 8-1
Rules for Conversion in Mixed
Expression Type (e)
Real

InteC)er

!
I

(v)

[-ouble-Precision I Lonical

Complex

I
I

INTEGER

Assign~ents

Variable Ty?e
I

F:EA.w

~lode

j.',..J....

P,C,I

I H,C,L

..... ,

:po
UJ

COEPLEX

C,f..

prohibited

Cfl
H

GJ
Z

<Xl

DO(JBLEPRECISION

C,H,L

prohibited I D

:s:
t!J

f-j

())

LOGICAL

R, I

I H, L

t-:l
t!J

3:
t!J

oC'rAL

R, I

LITERAL

D,B%

C,H%

j)#

B,C,L
_ D&

1-3

Table 8-1 (Cont.)
Rules for Conversion in Mixed Mode AssiqnDents
-

,
I --

Leqend
.

R
I
H

Direct replace~ent
Conversion between integer and floating-point with truncation
Heal part only
Set imaginary part to 0
High-order only
Set low-order part to 0

en
en
H

GJ
Z

Notes
00

t!J

Z
t-3

Octal nunbers with 13 to 24 digits are termed double octal.
Double octals require two storage locations. They are stored
right-justified and are padded with zeros to
fill
the
locations.

Use the first two words of the literal. If the literal is only
one word long, the second word is padded with blanks.

Use the first word of the literal.

To convert double octal nuobers to complex, the low-order octal
digits are assumed to be the imaginary part, and the high-order
digits are assumed to be the real part of the complex value.

t-3

t-3
trJ

Z
t-3

ASSIGNMENT STATEMENTS
8.3

LOGICAL ASSIGNMENT STATEMENTS

Use this type of assignment statement to assign values to variables
and array elements of type logical. Write the logical assignment
statement in the form
v=e
where v is one or more variables and/or array element names, and e
a logical expression.

Examples
Assuming that the variables L, F, M, and G are of
following statements are valid:

type

logical,

the

Sample Statement
L=.TRUE.

The contents of L is replaced by logical
truth.

F=.NOT.G

The contents of L is replaced by the
logical complement of the contents of G.

M=A.GT.T or M=A)T

If A is greater than T, the contents of
M is replaced by logical truth;
if A is
less than or equal to T, the contents of
M is replaced by logical false.
This
can also be read:
If A is greater than
T, then M is true, otherwise, M is
false.

L= ((I .GT.H) .AND. (J<=K))

The contents of L are replaced by either
the true or false resultant of the
expression.

8.4

ASSIGNMENT STATEMENT

ASSIGN (STATEMENT LABEL)

Use the ASSIGN statement to assign a statement label constant, i.e., a
1- to 5-digit statement number, to a variable name. Write the ASSIGN
statement in the form
ASSIGN n TO I
where n represents the statement number and I is a variable name.
example, the statement

For

ASSIGN 2000 TO LABEL
specifies that the variable
2000.

LABEL

represents

the

statement

with the exception of complex and double-precision, you
type of variable in an ASSIGN statement.

may

number
use

any

Once a variable has been assigned a statement number, FORTRAN-IO will
consider it a label variable.
If a label variable is used in an
arithmetic statement, the result will be unpredictable.

8-4

ASSIGNMENT STATEMENTS
Use the ASSIGN statement in conjunction with assigned GO TO control
statements
(Chapter
9).
The ASSIGN verb sets up statement label
variables that
are
then
referenced
in subsequent GO TO control
statement~i.
The following sequence illustrates the use of the ASSIGN
statement:
555 ']'AX= (A+B+C) *.05

ASSIGN 555 TO LABEL

GO TO LABEL

8-5

CHAPTER 9
CONTROL STATEMENTS

9.1

INTRODUCTION

FORTRA~-lO object programs normally execute statement-by-statement
in
the order in which they were ~resented to the compiler.
The following
source program control statements, however, enable you
to alter
the
normal sequence of statement execution:

9.2

GO TO

CONTINUE

STOP

PAUSE

GO TO CONTROL STATEMENTS

There are three kinds of GO TO statements:

Unconditional

Computed

Assigned

A GO TO control statement causes the statement that it
identifies
to
be executed next, regardless of its position within the program.
The
following paragraphs describe each type of GO TO statement.

9.2.1

Unconditional GO TO Statements

Write GO TO statements of this type in the form
GO TO n
where n is
the
label,
i.e.,
statement number,
of an executable
statement,
e.g.,
GO TO 555.
When executed, an unconditional GO TO
statement transfers control of the program to the
statement that
it
specifies.

9-1

CONTROL STATEMENTS
You may position an unconditional GO TO statement anywhere in
source program except as the terminating statement of a DO loop.

9.2.2

the

Computed GO TO Statements
----

Write GO TO statements of this type in the form
GO TO (N 1 , N2 , ... , Nk) E
where the parenthesized list is a list of statement numbers and E is
an arithmetic expression.
You may include any number of statement
numbers in the list of this type of GO TO statement~
however, each
number you give must be used as a label within the program or
subprogram containing the GO TO statement.
NOTE
comilla may optionally
parenthesized list.

the

The value of the expression E must be reducible to an integer value
that is greater than 0 and less than or equal to the number of
statement numbers given in the statement list.
If the value of the
expression E does not compute within the foregoing range, the next
statement is executed.
When a computed GO TO statement is executed,
the value of its
expression,
i.e., E, is conputed first.
The value of E specifies the
position within the given list of statement numbers of the number that
identifies the statement to be executed next.
For example, in the
statement sequence
GO TO (20, 10, 5)K
CALL XRANGC(K)
the variable K acts as a switch, causing a transfer to statement 20 if
K=l, to statement 10 if K=2, or to statement 5 if K=3. The subprogram
XRANGE is called if K is less than 1 or greater than 3.

9.2.3

Assigned GO TO Statements

Write GO TO statements of this type in either of the following forms:
GO TO K
GO TO K, (Ll ,L2, ... Ln)
where K is a variable name and the parenthesized list of the second
form contains a list of statement labels, i.e., statement numbers.
The statement numbers you give must be within the program or
subprogram containing the GO TO statement.
Assigned GO TO statements of either foregoing form must be logically
preceded by an ASSIGN statement that assigns a statement label to the
variable name represented by K.
The value of the assigned label
variable must be in the same program unit as the GO TO statement in
which it is used.
In statements written in the form
GO TO K,(Ll,L2, ... Ln)
9-2

CONTROL STATEMENTS
if K is not assigned one of the statement numbers given
statement list, the next sequential statement is executed.

the

logical,

and

Examples
GO TO STATI
GO TO STATl,(177,207,777)

9.3

IF STATEMENTS

There are three kinds of
logical two-branch.

9.3.1

statements:

arithmetic,

Arithmetic IF Statements

write IF statements of this type in the form
IF(E)Ll,L2,L3
where (E) is an expression enclosed within parentheses and LI, L2, L3
are
the
labels,
i.e., statement numbers, of three executable
statementEi.
This type of IF statement transfers control of the program to one of
the given statements according to the computed value of the given
expressions.
If the value of the expression is:
1.

Less than 0, control
identified by Ll;

transferred

the

statement

Equal to 0, control
identified by L2;

transferred

the

statement

Greater than 0, control
identified by L3.

the

statement

transferred

You must give all three statement numbers in arithmetic IF statements;
the expression given may not compute to a complex value.
Examples
Sample Statement
IF (E'I'A)4, 7, 12

Transfers control to statement 4 if
ETA is negative, to statement 7 if
ETA is 0, and to statement 12 if
ETA is greater than o.

IF(KAPPA-L(10))20, 14, 14

Transfers control to statement 20
if KAPPA is less than the lath
element of array L and to statement
14 if KAPPA is greater than or
equal to the lath element of array
L.

9-3

CONTROL STATEMENTS
9.3.2

Logical IF Statements

write IF statements of this type in the form
IF (E) S
where E is any expression enclosed in parentheses and S is a
executable statement.

complete

Logical IF statements transfer control of the program either to the
next sequential executable statement or the statement given in the IF
statement, i.e., S, according to the com~uted logical value of the
given expression.
If the value of the 1iven logical expression is
true (negative), control is given to the executable statement within
the IF statement.
If the value of the expression is false (positive
or zero), control is transferred to the next sequential executable
program statement.
The statement you give in a logical IF statem~nt may be any FORTRAN-IO
executable statement except a 00 statement or another logical IF
statement.
Exam~les
Sam~le

Statement

IF (T.OR.S) X=Y+l

Performs
an
arithmetic
replacement operation if the
result of IF is true.

IF (Z.GT.X(K)) CALL SWITCH(S,Y)

Performs a subroutine call
the result of IF is true.

IF (K.EQ.INDEX) GO TO 15

Performs
transfer
is true.

9.3.3

Logical Two-Branch IF

an
unconditional
if the result of IF

Statement~

write IF statements of this type in the form
IF

(E)

Nl, N2

where E is any parenthetical expression, and Nl and N2
labels defined within the program unit.

are

statement

Logical two-branch IF statements transfer control of the program to
either statement Nl or N2, dependin1 on the computed value of the
given expression.
If the value of the given logical expression is
true (negative), control is transferred to statement Nl.
If the value
of the expression is false (positive or zero), control is transferred
to statement N2.
Note that you must number the statement immediately following the
logical two-branch IF so that control can later be transferred to the
portion of code that was skipped.

9-4

CONTROL STATEMENTS
Examples
Sample Statement
IF (LOG 1) 10,20

Transfers control to statement 10
if LOGl is negative;
otherwise
transfers control to statement 20.

IF (A.LT.B.AND.A.LT.C)

Transfers control to statement
if A is less than both Band
transfers control to statement
if A is greater than or equal
either B or C.

31,32

31
2;
32
to

DO STl\TEt1ENT

9 .4

DO statements simplify the coding of iterative procedures;
in the following form:

write them

Indexing Parameters
DO N I

~rr

Ml'~M2'~
INCREMENT
PARAMETER

TER~lINAL

STATEMENT
LABEL
INDEX
VARL1\BLE

TERMINAL
PARAMETER
INITIAL
PARAMETER

whE~

re
1.

Terminal Statement Label N is the statement number of the
last statement of the DO statement range. The range of a DO
statement is defined as the series of statements that follows
the DO statements up to and including its specified terminal
:3tatement.

Index Variable I is an unsubscripted variable whose value is
defined at the start of the DO statement operations. The
index variable is available for use throughout each execution
of the range of the DO statement, but its value should not be
altered within this range.
It is also available for use in
the program when:
a.

control is transferred outside the range of the DO loop
by a GO TO, arithmetic IF or RETURN statement located
within the DO range,

a CALL is executed from within the DO statement
that uses the index variable as an argument, and

if an input-output statement with either or both the
options END= or ERR= (Chapter 10) appears within the DO
statement range.

9-5

range

CONTROL

STATEME~TS

I,
its
Initial Parameter Ml assi3ns the index variable,
initial val~e.
This parameter may be any variable, array
element, or expression.

Terminal Parameter M2 provides the value that determines how
~any repetitions of the DO statement range are performed.

Increment Parameter M3 specifies the value to be added to the
initial parameter (Ml) on completion of each cycle of the DO
loop.
If M3 and its preceding comma are omitted, M3 is
assumed to be equal to 1.

~n indexing parameter may be any arithmetic
expression resulting in
either a 90sitive or negative value.
The values of the indexing
parameters are calculated only once, at the start of each DO-loop
operation.
The number of times that a DO loop will execute is
specified by the formula:
~AX

((M2-Ml)/M3+l,1)

Since the count is computed at the start of a DO loop operation,
changing the value of the loop index variable within the loop cannot
affect the number of times that the loop is executed. At the start of
a DO loop operation,
the index value is set to the value of the
initial ,?arameter
(Ml), and a count variable
(generated by the
comriler)
is set to the negative of the calculated count. At the end
of each DO loop cycle, the value of the increment parameter
(M3)
is
added to the index variable, and the count variable is incremented.
If the number of specified iterations have not been performed, another
cycle of the loop is initiated.
One execution of 3 DO loop range is always performed regardless of the
initial values of the index variable and the indexing parameters.
Exit from a DO loop operation on completion of the number of
iterations specified by the loop count is referred to as a normal
exit.
In a normal exit, control passes to the first executable
statement after the DO loop range terminal statement, and the value of
the DO statement index variable is considered undefined.
Exit from a DO loop may also be accomplished by a transfer of control
by a statement within the DO loop range to a statement outside the
range of the DO statement (Paragraph 9.4.3).

9.4.1

Nested DO Statements

One or more DO statements may be contained, i.e., nested, within the
range of another DO statement. The following rules govern the nesting
of DO statements.

9-6

CONTROL STATEMENTS
1.

The range of each nested DO statement must be entirely within
the range of the containing DO statement.
Example
Valid

Invalid

DO I

~~
2.

The range of
DO 2 is outside
that of DO 1.

The ranges of nested DO statements cannot overlap.
Example
Valid

Invali.d

DO 1

DO 2

D03

The ranges of
loop DO 2 and
DO 3 overlap.

More than one DO loop within a nest of DO loops may end on
the same statement. When this occurs, the terminal statement
is considered to belong to the innermost DO statement that
ends on that statement. The statement label 4 of the shared
terminal statement cannot be used in any GO TO or arithmetic
IF statement that occurs anywhere other than within the range
of the DO statement to which it belongs.
Example
D04

All the DO statements
share the same terminal
statement, however, it
belongs to DO 4.

D04

9-7

CONTROL STATEMENTS
Extended Range

9.4.2

The extended range of a DO statement is defined as the S2t of
statements that execute between the transfers out of the innermost DO
statement of a set of nested DOs and the transfer back into the range
of this innermost DO statement. The extended range of a nested DO
statement is as follows:
DO I
DO 2

003

- - - _ a (out)

----(in)

E
Extended Range

The following rules govern the use of a DO statement extended range:
1.

The transfer out statement for an extended range ogeration
must be contained by the most deeply nested DO statement that
contains the location to which the return transfer is to be
made.

A transfer into the range of a DO statement is permitted only
if the transfer is made from the extended range of that DO
statement.

The extended range of a DO statement must not contain another
DO statement.

9-8

CONTROL STATEMENTS
4.

The extended range of a DO statement cannot change the
variable or indexing parameters of the DO statement.

You may use and return from a subprogram within
range.

9.4.3

index

extended

P E~ r in itt e d T ran s fer 0 per at ion s

The following rules govern the transfer of program control from within
a DO statement range or the ranges of nested DO statements:
1.

A transfer out of the range of any DO loop is permitted at
any time.
When such a transfer executes, the value of the
controlling DO statement's index variable is defined as the
current value.

A transfer into the range of a DO statement is permitted
it is made from the extended range of the DO statement.

You may use and return from
range of any:

the

a.
b.
c.

subprogram

from

within

DO loop,
nested DO loop, or
extended range loop (in which you leave the loo~ via a GO
TO, execute statements elsewhere,
and return to the
original loop).

The following examples illustrate the transfer
from within the ranges of nested DO statements:
Valid Transfers
DI
D2

[

--- .
extended range

~--

Invalid Transfer
DI

4------

9-9

operations

permitted

CONTROL STATEMENTS
9.5

CONTINUE STATEMENT

You may place CONT~NUE statements anywhere in the source program
without
affecting the program sequence of execution.
CONTINUE
statements are commonly used as the last statement of a DO statement
range in order to avoid ending with a GO TO, PAUSE, STOP, RETURN,
arithmetic IF, another DO statement, or a logical IF statement
containing any of the foregoing statements. Write this statement as
12 CONTINUE
Example
In the following sequence, the labeled CONTINUE statement
legal termination for the range of the DO loop.

provides

00 45 ITEM=l,lOOO

5TOCK=NVNTRY (ITEM)
CALL UPDATE (STOCK,TALLY)
IF(ITEM.EQ.LAST) GO TO 77
45 CONTINUE

77 PRINT 20, HEADING,PAGENO

9.6

STOP

ST~TEMENT

Execution of the STOP statement causes the execution of the object
program to be terminated and returns control to the DECsystem-lO
Monitor.
A descriptive message may optionally be included in the STOP
statement to be output to your I/O terminal immediately before program
execution is terminated. Write this statement like this:
STOP
STOP 'N'
or
STOP n,
where 'N' is a string of ASCII characters enclosed by single quotes
and n is an octal string up to 12 digits. The string N or the value n
is printed at your I/O terminal when the STOP statement executes. The
string N may be of any length.
(Continuation lines may be used for
large messages.)

9-10

CONTROL STATEMENTS
Examples
STOP 'Termination of the Program'
or
STOP 7777

9.7

PAUSE STATEMENT

Execution of a PAUSE statement suspends the execution
program and gives you the option to:
1.

Continue execution of the program

Ex i t

Initiate a TRACE operation (Paragraph 9.7.1).

the

object

The permitted forms of the PAUSE statements are:
1.

PAUSE

PAUSE 'literal string'

PAUSE nr where n is an octal string up to 12 digits.

Execution of a PAUSE statement of any of the
the standard instruction:

foregoing

forms

causes

TYPE G TO CONTINUE, X TO EXIT, T TO TRACE
to be printed at your terminal. If the form of the PAUSE statement
contains either a literal string or an integer constant, the string or
constant prints on a line preceding the standard message.
For
example, the statement
PAUSE 'TEST POINT A'
causes the following to be printed at your terminal:
TEST POINT A
TYPE G TO CONTINUE, X TO EXIT, T TO TRACE
The statement
PAUSE: 1
causes the following to be printed at your terminal:
PAUSE 000001
TYPE G TO CONTINUE, X TO EXIT, T TO TRACE

9-11

CONTROL STATEMENTS
9.7.1

T(TRACE) Option

The entry of the character T in response to the message output by the
execution of a PAOSE statement starts a TRACE routine. This routine
causes a complete history of all subroutine calls made during the
execution of the program, up to the execution of the PAOSE statement
to be printed at your terminal. The history printed by the TRACE
routine consists of:
1.

The names of all subroutines called, arranged in the
order of their call;

reverse

The absolute location (written
called subroutine;

The name of the calling subroutine plus an offset factor and
the absolute location (written within parentheses) of the
statement within the routine that initiated the call;

The number
brackets) ;

within

angle

An alphabetic code (written within square brackets)
specifies
the
types
of each argument involved .
alphabetic codes used and the meaning of each are:

that
The

arguments

within

involved

Code Character
U
L
I
F

a
S
D
C
K

parentheses)

(written

the

Type Specified
Undefined type;
the use of the
argument will determine its type.
Logical
INTEGER
Single-precision REAL
Octal
Statement Number
Double-precision REAL
COMPLEX
A literal or constant

Example
The following printout illustrates the execution of the
PAUSE
statement
PAUSE 'TEST POINT A'", the entry of a T character to
initiate the TRACE routine, the resulting trace printout, and the
entry of the character G to continue the execution of the program.
II

TEST POINT A
TYPE G TO CONTINUE, X TO EXIT, T TO TRACE.
*T
NAME
(LaC)
«--- CALLER (LaC)
<#ARGS> [ARG TYPES]
TRACE.
(414056) «--PAUS.+141(376) <#1>
[U]
PAUSe
( 23 5)
<<- - MA IN. + 4 ( 1 5 1 )
<# 1 >
[ U]
TYPE G TO ·CONTINUE, X TO EXIT, T TO TRACE.
*G

9-12

CONTROL STATEMENTS
In addition to its use with the PAUSE statement,
TRACE routine directly, using the form

you

may

call

the

CALL TRACE
or as a function, using the form
X=TRACE(x)
Execution of the foregoing statements starts the TRACE routine, which
prints the history of all subprogram calls made during the execution
of the program, up to the execution of the CALL statement or up to the
execution of the function, respectively. The history printed by the
TRACE routine under these circumstances is as described in the
preceding paragraph.

9-13

CHAPTER 10
I/O STATEMENTS

10.1

DATA TRANSFER OPERATIONS

between
FORTRAN-IO I/O statements permit the transfer of data
processor storage (core) and peripheral devices and/or between storage
locations.
Data in the form of logical records may be transferred by
use of an a) sequential, b) random access, c) append transfer mode, or
d) dump mode. The areas in core from which data is to be taken during
output
(write)
operations and into which data is stored during input
(read) operations are specified by:
1.

A list in the I/O statement that initiated the transfer

A list defined by a NAMELIST statement, or

Between a specified FORMAT statement and the external medium.

The type and arrangement of transferred data may be specified by
format specifications located in either a FORMAT statement or an array
(formatted I/O), or by the contents of an I/O list
(list.-directed
I/O) .
The following sections describe the statements
required to initiate I/O transfer operations.

10.2

and

data

format

TRANSFER MODES

The characteristics and requirements of the a) sequential, b)
random
access, and c)
append data modes are described in the following
para,)rarhs .

10.2.1

Sequential Mode

-----------

Records are transferred during a sequential mode of operation in the
same order they appear in the external data file.
Each I/O statement
executed in a sequential mode transfers the record immediately
following the last record transferred from the accessed source file.

10.2.2

Random Access Mode

This mode permits access to and transfer of records from a file in any
desired order. Random access t.ransfers, however, may be made only to
(or from)
a device that permits
random-type
data
addressing
operations, i.e., disk, and to files that have previously been set up
10-1

I/O STATEMENTS
for random access transfer operation.
Files for
random access must
contain a specified number of identically sized records that may be
accessed, individually, by a record number.
You may use the FORTRAN-lO OPEN statement see Chapter 12 subroutine call to DEFINE FILE to set up random access files.

Use the OPEN statement to establish a random access mode to permit the
execution of random access data transfer operations.
The OPEN
statement should logically precede the first I/O statement for the
specified logical unit in the user source program.

10.2.3

Append Mode

This mode is a special version of the sequential transfer mode:
Use
it only for sequential output (write) operations. The append mode
permits you to write a record immediately after the last logical
record of the accessed file.
During an append transfer, the records
already in the accessed file remain unchanged.
The only function
performed is the appending of the transferred records to the end of
the file.
You must use an OPEN statement to establish
append I/O operations can be executed.

10.3

append

mode

before

I/O STATEMENTS, BASIC FORMATS AND COMPONENTS

The majority of the I/O statements described in this chapter are
written in one of the following basic for~s or in some modification of
these forms:
Basic Statement Forms
Keyword
Keyword
Key \'1 0 r d
Keyword
Keyword
Keyword

(u, f) list
(u#R,f)list
( u , *) 1 i s t
(u,N)
(u)list
(u#R)list

Use
Formatted I/O Transfer
Random Access Formatted I/O Transfer
List-Directed I/O Transfer
NAMELIST-Controlled I/O Transfer
Binary I/O Transfer
Random Access Binary I/O Transfer

where
Keyword

the statement name (READ or WRITE)

FORTRAN-lO logical unit number

list
#R

FORMAT statement number in the current program
unit or the name of an array that contains the
desired format specifications
I/O list
the delimiter # followed by the number
in an established random-access file

reco~d

*
N

symbol specifying a list-directed I/O transfer
the name of an I/O list
statement

defined

NAMELIST

The following paragraphs provide details of the foregoing components.
10-2

I/O STA'rEMENTS
10.3.1

I/ll Statement Keywords

The keywords (names) of the
this chapter are:
1.
2.
3.
4.
5.

10.3.2

READ
REREAD
ACCEPT
FIND
DECODE

6•
7•
8.

10.

FORTRA~-lO

I/O

statements

described

WRITE
PRINT
PUNCH
TYPE
ENCODE

FOHTRAN-IO Logical unit Numbers

Decimal numbers identify the physical devices used for most FORTRAN-IO
I/O operations.
During compilation, the compiler assigns default
logical unit numbers for the REREAD, READ, ACCEPT, PRINT, PUNCH and
TYPE statements.
Default unit numbers are negatively signed decimal
numbers that you cannot access.
You may make the logical device assignments at run time, or you may
use the standard assignments contained by the FORTRAN-IO Object Time
System
(FOROTS).
Table 10-1 lists the standard logical device
assignment£..
We recommend that you specify the device explicitly in
the OPEN statement.

10.3.3

FORMAT Statement References

A FORMAT statement contains a set of format specifications that
defines the structure of a record and the form of the data fields
comprising the record.
Format specifications may also be stored in an
array rather than in a FORMAT statement.
(Refer to Chapter 13 for a
complete description of the FORMAT statement.)
The execution of an I/O statement that includes either a FORMAT
statement number or the name of an array that contains format
specifications causes the structure and data of the transferred record
to assume the form specified in the referenced statement or array.
Records transferred under the control of a format specification are
referred to as 'Iformatted records. Conversely, records transferred
by I/O statements that do not reference a format specification are
ref err edt. 0 as· 1 un for mat ted II r e cor d s . Duri n gun for ill a t ted t ran s fer s ,
data is transferred on a one-to-one correspondence between internal
(processor)
and external
(device)
locations, with no conversion or
formatting operations.
ll

Unformatted files are binary files divided into records by FORTRAN-IO
embedded control words;
the control words are invisible to you. You
cannot prepare files of this type without using FOROTS.
Unformatted
files are for use only within the FORTRAN-IO environment.

10-3

Table 10-1
FORTRAN-10 Logical Device
Device/Function

Default

Filena~e

FORT~AN

Assign~ents

Logical Unit

Num~er

esc

Standard Devices*

FCRxx.DAT

r-'

I
~

DSK

01
02
03
04
OC:
.J

06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21

P~R

PTEDIS
D'TAl
DTA2
DTA3
DTA4
DTAS
DTA6
DTA7
[v1TAO
t'l'IAl
l'1'I'A2
FORTR
DSK
DSK
DSK
DSK

ILLEGAL
Disk
Card Reader
Line Frinter
Console Telety?e
User's 'I'elety?e
E-aper Tal?e Reader
Paper Tape Punch
[; i spl-a y
CECtaoe

DSK
CDR
LPT
CTY
TTY

j
CECtape
r-1agnet ic Tape

+
Assignable
Device
DISK

23
24

*1he total number of standard devices permitted is
parameter.

UJ
1-3
;.J:::'

"'-

installation

1-3
trl

:s
t'1
z

J-;3
Lil

Table 10-1 (Cant.)
FORTRAN-IO Logical Device Assignments
Device/Function

Default

Fi1ena~e

FORTRAN Logical unit NUQber

Use

Standard Devices*
DEV1
DEV2

FORxx.DAT

DEV3

DEV4
DEV5
I--'

I
l.il

D£V63

Assignable Devices

25
26
27
28

"'-...

1-3

+
FOF-63.DAT

Disk

Default Levices (inaccessible to the user)

1-3
M
;3:
M

1-3

REREAD
CDR
TTY
LPT
PTP
TTY

Current file
FORCDR.DAT

FORTTY.DAT
FORLPT.DA'I'
F'ORPTP.DAT
F'ORTTY.DAT

FEREAD statement
READ statement
ACCEPT statement
PRINT statement
PUNCH stateGent
TYPE stateP.1ent

-6
-5
-4
-3
-2
-1

*The total number of standard devices permitted is
parameter.

installation

I/O STATEf·1ENTS
10.3.4

I/O List

-----

An I/O list specifies the names of variables,
arrays,
and array
elements to which input data is to be assigned or from which data is
to be out()ut.
Implied DO constructs
(Paragraph 10.3.4.1), which
specify sets of array elements, lnay also be included in I/O lists.
The number of items in a statement list determines the amount of data
to be transferred during each execution of the state~ent.

10.3.4.1 Implied DO Constructs - When an array name is given
in an
I/O list,
all elements of the array are transferred in the order
described in Chapter 3 (Paragra()h 3.5.3).
If only a specific set of
array elements is involved,
they may be specified in the I/O list
either individually or in the form of an i~plied DO construct.
~rite

implied DOs within parentheses in a format similar to that of DO
statements.
They may contain one or more variable, array, and/or
array element names, delimited by commas and
followed by indexing
parameters that are defined as for DO statements.

The general form of an implied DO is
(name(3L) ,I=Ml,M2,M3)
where
name

an array name

the subscript list
clement identifier

the index control variable that may represent a
subscript appearing in a preceding subscript list

Ml,M2,M3

the
indexing
parameters
that
specify,
respectively,
the
initial,
terminal,
and
increment values that control the range of I.
If
M3 is omitted (with its preceding comma), a value
of 1 is assumed.

array

Examples
(A(S) ,S=1,5)

Specifies the first fiv€ elements of the
one-dimension array A, i.e., A(l), A(2),
A(3), A(4), A(5).

(A(2,S) ,S=1,10,2)

Specifies the elements A(2,1), A(2,3),
.1\(2,5), A(2,7), A(2,9) of array 7\.

(1,1=1,5)

Specifies the integers 1,2,3,4, and 5.

As stated previously, implied DO constructs may also
more variable names.

contain

one

I, J, B, and C must be integer variables.

((A(B,C) ,B=l,lO) ,C=l,lO) ,I,J

Specifies a 10 X 10 set of elements
of array A, the location identified
by I, and the location identified
by ,J.
10-6

I/O

STA'rEMEI~TS

You may also nest implied DO constructs.
one or more sets of indexing parameters.

Nested implied DOS

~ay

Example
( (A (~J , K) , J =1 , 5) , D ( K) , K =1 , 1 0 )

Specifies a 5 X 10 set of elements
of
array
~
and the first 10
elements of array D.

When you specify an array or set of array elements as either a storage
or transmitting area for I/O purposes, the array elements involved are
accessed in ascending order with the value of the first subscript
quantity varying most rapidly and the value of the last given
subscript increasing to its maximum value least rapidly.
For exaDple,
the e 1 e mE~ n t s 0 fan a r ray dim ens ion e d as TAB ( 2 , 3 ) are a c c e sse din the
order:
TAB(l,l)
TAB(2,1)
TAB (1,2)
TAB(2,2)
TAB (1,3)
TAB(2,3)

10.3.4.2 Formatted Record Handling - Data is processed under
for~at
con t r 0 1 ~; 0
t hat e a c h i t e min the I/O 1 i s t i s mat c h e d wit h a fie 1 d
descriptor in the FORMAT statement.
If the end of the FORMAT
s?ecification is reached and nore items remain in the I/O list, a new
line or record is established and the data processing is restarted,
either:

at the first item in the FORMAT specification or,

(if parenthesized sets of FORMAT specifications exist within
the FORMAT specification) with the last set within the fORr1AT
specification.

On input, if the record is exhausted before the data transfers are
completed, the remainder of the transfer is completed as if the record
were extended with blanks. See Section 13.2.2 for more details.

10.3.5

Specification of Records for Random Access

You must identify records to be transferred in a random access mode in
an I/O statement by an integer expression or variable preceded by an
apostrophe used as a delimiter, e.g., '101.
NOTE
You may use a pound sign (#) in place of
the apostrophe ('), e.g., both #101 and
'101 are accepted by fORTRAN-lO.

10-7

I/O STATEMENTS
10.3.6

List-Directed I/O

The,use of an asterisk in an I/O statement in place of a FORMAT
statement number causes the specified transfer operation to be
"list-directed".
In a list-directed transfer, the data to
be
transferred and the type of each transferred datum are specified by
the contents of an I/O list included in the I/O command used.
The
transfer of data in this mode is performed without regard for column,
card, or line boundaries. The list-directed mode is specified by the
substitution of an asterisk (*) for the FORMAT statement reference,
i.e., f, of an I/O statement. The general form of a list-directed I/O
statement is
keyword (u,*) list
Example
READ (S,*)I,IAB,M,L
You may use list-directed transfers to read data from
inpu~ device, including an input ,keyboard terminal.

any

acceptable

NOTE
Do not use device positioning commands,
such as BACKSPACE, SKIP RECORD, etc., in
conjunction
with
list-directed
I/O
operations.
If you do, the results are
unpredictable.
Data for list-directed transfers should consist of alternate constants
and
delimiters.
The constants used should have the following
characters:
1.

Input constants must be of a type acceptable
Octal constants, although acceptable, are
list-directed I/O operations.

to
no~

FORTRAN-lO.
permitted in

Literal constants must be enclosed within single quotes,
e.g.,
'ABLE'.
A quoted string which is too long to fit in
one element of the input list will be placed in adjacent
elements and will be padded with blanks. If a quoted string
is being placed in any array and it fills more than one
element of the array, the remaining elements of the array
will be unchanged. In this case, it is assumed that the user
meant for the long string to go into the array and for any
following data to go into the rest of the input list. If the
string fits into one element of the array, the array will
continue to be filled.

Blanks are delimiters; therefore, they are not permitted
any but literal constants.

You may omit decimal points from real constants that do not
have a fractional part. FORTRAN-IO assumes that the decimal
point follows the rightmost digit of a real constant.

Complex constants must be enclosed in parentheses.

10-8

I/O STl\TEMENTS
Delimiter~)

in data

for

list-directed

input

must

com91y

with

the

following :
1.

Delimiters may be either commas or blanks.

Delimiters may be either preceded by or followed by any
of blanks, carriage return/line feed characters, tabs,
or line terminators: any such combination is considered by
FORTRAN-IO as being only a single delimiter.
nu~ber

Represent a null (the complete absence of a datum)
by two
consecutive commas that have no intervening constant(s}. You
may place any number of blanks, tabs, carriage return/line
feed characters, or end-of-input conditions between the
commas of a null. Each time you specify a null item in the
input
1ata, its corresponding list element is skipped
(unchanged). The following illustrates the effect of a null
input:
INPUT Items

101 , , A' , tab, , NOI ' ,

Corresponding
I/O List Items

\ .Lr7s.N7SER

Resulting
Contents of
List Items

lOl."A un- NOI
changed
lAB

I I I /

Slashes (/) cause the current input operation to terminate
even if all the items of the directing list are not filled.
The contents of items of the directing I/O list that either
are skipped
(by null inputs) or have not received an input
datum before the transfer is terminated remain unchanged.
Once the I/O list of the controlling I/O statement is
satisfied, the use of the / delimiter is optional.

Once the I/O list has been satisfied
(values have been
transferred to each item of the list), any items remaining in
the input record are skipped.

Constants or nulls in data for list-directed input may be
repetition factor so that an item is repeated.

assigned

The repetition of a constant is written as
r*K
where r is an integer constant that specifies the number of times
constant represented by K is to be repeated.

the

The repetition of a null is written
asterisk.

integer

Examples
10*5

3*'ABLE'
3*

represents 5,5,5,5,5,5,5,5,5,5
represents 'ABLE' ,'ABLE' ,'ABLE'
represents null,null,null

10-9

followed

I/O S'r,Z\TEMENTS
10.3.7

NAMELIST I/O Lists

You may define one or more lists by a NAMELIST statement (Chapter 11).
Each I/O list defined in a NAMELIST statement is identified by a
unique (within the routine)
1- to 6-character name that may be
referenced by one or more READ or WRITE statements. The first
character of each I/O list name must be alphabetic.
By using the
L~AMELIST
statement, you eliminate the need for specifying the entire
I/O list.
I/O statements that reference a NAMELIST-defined I/O list cannot
contain either a FORMAT statement reference or an I/O list. You
cannot use NAMELIST-controlled I/O operation to transfer octal numbers
or literal strings.
You may use only NAMELIST-controlled READ/WRITE statements to bring
Format
in/write out records formatted in the following manner.
records for NAMELIST-controlled input operations as follows:
$NAME 01,02,03 ... Dn$
where
1.

$ symbols delimit the beginning and end of the record.
The
first $ must be in column 2 of the input record; column 1
;nust be blank.

NAME is the name of a NAMELIST-defined input list. The named
list identifies the processor storage locations that are to
receive the data items read from the accessed record.

01 throu~h On are pairs of the form "variable=value"
the value is assigned to the associated variable.
items cannot be octal numbers or literal strings.

where
These

NOTE
Do not use device positioning commands
such as BACKSPACE, SKIP RECORD, etc., in
conjunction with NAMELIST-controlled I/O
operations.
If you do, the results are
unpredictable.
See Chapter 11 for more information on NAMELIST I/O transfers.

10.4

OPTIONAL READ/WRITE ERROR EXIT AND END-OF-FILE ARGUMENTS

You may optionally add either or both an error exit or an end-of-file
argument to the portion in parentheses of any form of the READ and
WRITE statements when a unit is specified.
write the error exit argument as ERR=c where c is a statement number
in the current program unit.
Using this ar1ument terminates the
current I/O operation and transfers program control to the statement
identified by the argument if an error is detected.
For example, the
detection of an error during the execution of
READ(lO,77,ERR=101)TABLE,I,M,J

10-10

I/O STATEMENTS
terminates the input operation and transfers program control to
statement 101. See the FORTRAN-IO Library Subroutine ERRSNS (Cha9ter
15) to find out how to identify the actual error that occurred.
When an ERR= transfer occurs, all items on the input list and
implied DO indexes on input or output lists become undefined.

all

Write the end-of-file argument as END=d, where d is a statement number
in the current program unit.
This branch, when taken, stops the
current I/O operation and transfers program control to the statement
identified by the argument.
In the example below, the detection of 3n
end-of-file condition during the execution of
READ(10,77,END=50)TABLE,I,M,J
results in the transfer of control to statement 50.
When an END= transfer occurs, all items on the input list receive the
value zero and all implied DO indices on input lists become undefined.
If the END= argument is not present, but an ERR= argument is, an
end-of-file
(EOF) condition is treated as a user-trappable error.
If
neither the ERR= nor the END= argument is present and an end-of-file
condition is detected, a message is printed, the file is closed,
program execution is terminated,
and control is returned to the
monitor.

10.5

READ STATEMENTS

READ statements transfer data from peripheral devices into specified
processor storage locations.
The permitted forms of this type of
input statment permit READ statments to be used on both sequential and
random
access
transfer
modes
for
formatted,
unformatted,
list-directed, and NAMELIST-controlled data transfers.

10.5.1

Sequential Formatted
READ Transfers
-_._ - --. - - - - - - - - - - ..

Descriptions of the READ statements that
sequential transfer of formatted data follow:
1.

:nay

used

for

the

Form:

READ (u,f)list

Use:

Input data from logical
unit
u,
for:natted
according to the specification given in f, into
the processor storage locations identified in
input list.

Example:

READ (10,555)TABLE(lO,20) ,ABLE,BAKER,CH,l\RL

Form:

READ (u, f)

Use:

Input the data from logical unit u directly into
either a Hollerith
(H)
field descriptor or a
literal field descriptor given within the format
specifications of the referenced FORMAT statement.
If the referenced FORMAT statement does
not
contain either of the foregoing types of format
field descriptors, the input record is skipped.
If a required field descriptor is ?resent, its
contents are replaced by the input data.

Example:

READ ( 15 ,101 )
10-11

I/O STATEMENTS
3.

Form:

READ f

Use:

Input the data from the READ default device
(card
reader) directly into either a Hollerith (H) field
descriptor or a literal field descriptor given
within the format specifications of the referenced
FORMAT statement.
If the
referenced
FORMAT
statement does not contain either of the foregoing
types of for~at field descriptors,
the input
record is skipped.
If a required field descriptor
is present, its contents are replaced by the input
data.

Example:

Form:

READ f,list

Use:

Input the data from the READ default device
(card
reader)
into the processor storage locations
identified in the input list. The input data is
formatted according to the specifications given in
c

Exalilple:

10.5.2

Sequential

READ 15, ARRAY (20,30)

Unfor~atted

Binary READ Transfer

------------------------~-.--.

You may use only the following form of the READ statement for
sequential transfer of unformatted input FORTRAN binary data:

the

Forlll:

READ (u)list

Use:

Input one logical record of data from logical unit
u into processor storage as the value of the
location identified in list. You may read only
binary files output by a FORTRAN-IO unformatted
WRITE statement by this type of READ statement.
NO'TE
If you use the form READ
(u) ,
one
unformatted input record will be skipped.

Example:

10.5.3

READ (10)

BINFIL (10,20,30)

Sequential List-Directed READ Transfer

You may use the following forms of the READ statements
sequential, list-directed input transfer:
1.

control

For m:

READ(u,*)list

Use:

Read data from logical device u into processor
storage as the value af the locations identified
in list.
Each input datum is converted,
if
necessary,
to the type of its assigned list
variable.

Example:

READ(lO,*) IARY(20,20) ,A,B,M
10-12

I/O ST.1\TEMENTS
2.

10.5.4

Form:

READ *,list

Use:

Read the data from the READ default device
(card
reader)
into the processor storage locations
identified in the input list. Each input datum is
converted, if necessary, to the type of its
assigned list variable.

Example:

READ *,ABEL(10,20) ,I,J,K

~equential

NAMELIST-Controlled READ Transfers

You may use only the following form of the READ statement to
a sequential NAMELIST-controlled input transfer:

10.5.5

Form:

READ(u,N)

Use:

Read data from logical unit u into processor
storage as the value of the locations identified
by the NAMELIST input specified by the name N.
The input data is converted to the type of
assigned variable if type conflicts occur.
Only
input files that contain records formatted and
identified for NAMELIST operations
(Paragraph
10.3.7)
may be read by READ statements of this
form.

Random Access Formatted READ Transfers

You may use only the following form of the READ statement to
a random access formatted input transfer:

10.5.6

initiate

Form:

READ (u#R,f)list

Use:

Input data from record R of logical unit u.
Format each input datum according to the format
specifications of f and place into processor
storage as values of the locations identified in
list. Only disk files that have been set up by
either an OPEN or DEFIN~ FILE statement may be
accessed by a READ statement of this form.
(If
record R has not been written, an error results.)

Example:

READ ( I # 20, I 0 0) I, X (J)

Random Access Unformatted READ Transfers

-------------------

You may use only the following form of the READ statement to
a random access unformatted input transfer:

10-13

initiate

I/O STATEMEI'JTS
For In:

READ (u#R)list

Use:

Input data from record R of logical unit u. ~lace
the input data into processor storage as the value
of the locations identified in list. Only binary
files that have been output by an unformatted
random access WRITE statement may be accessed by a
READ statement of this form.
(If record R has not
been written, an error results.)

Example:

READ (1#20) BINFIL
Read record

num~er

20 into aLray

BI~FIL.

If the form READ (u#R) is used,
cause
logical
input record
skipped.

10.6

it
R

will
be

SUMMARY OF READ STATEMENTS

Table 10-2 summarizes the various forms of the READ statements.

Su~mary
r--------------

Table 10-2
of READ Statements

---------------------------------------- - - - - - - - - -

Type of rransEer

Transfer Mode
- -----------------,---------------------------

Sequential

Random Access

----------------------- --------- - - - - - - - - - - - - - - - - - + - - - - - - - - - - - - - - - l

Formatted

READ(u,f)list
RE.:,\D (u, f)
READ f,list
READ f

READ(u#R,f)list

Unformatted

READ(u)list
READ(u)

READ(u#R)list
READ(u#R)

List-Directed

READ(u,*)list
READ *,list

NAMELIST

READ(u,N)

Note:

You may include the ERR=c and END=d arguments in any of
the
above
READ
statements.
When included, the
foregoing arguments
must
be
last,
e.g.,
READ
(10,20,END=lOl,ERR=500)ARRAY(50,100) .
-----------------------------------------------'

10.7

REREAD STATEMENT

The REREAD statement causes the last record read from the last
input device to again be accessed and processed.

10-14

active

I/O STATEMENTS
(READ)
You cannot use the REREAD feature of FORTRAN-IO until an input
transfer
from a
file
has been accomplished.
If you use REREAD
prematurely, an error results.
Once a record has been accessed by a
formatted
READ statement,
the
record
transferred may be
reread as many times as desired.
In a
formatted transfer, you may use the same or new format
sgecification
by each successive REREAD statement.
You may use the REREAD statement only for
sequential
transfers.
The form of the REREAD statement is:

data

Form:

REREAD f,list

Use:

Reread
the last
record
read during
the
last
initiated
READ operation and
input the data
contained by the record into the processor storage
locations specified in the input list.
Format the
data read according to the
format
specifications
given in statement f.

Example:

DIMENSION ARRAY{lO,lO) ,FORMA(lO,lO) ,FOR~1B(10,10),
1
FORMC(lO,lO)
90 READ(16,100)ARRAY

100

formatted

FOR~mT

(-----)

110 REREAD 100,FORMA
115 REREAD 150,FORMB
120 REREAD 160,FORMC
150 FORMAT (-----)
160 FORMAT (-----)
In the above sequence, statement 90 inputs data formatted according to
statement 100 into the array ARRAY.
Statement 110 reads the record
read by statement 90 and inputs the data formatted as in the
initial
READ operation into the array FORMA.

.
'

Statement 115 reads the record read by statement 90 and
inputs
data formatted according to statement 150 into the array FORMS .

the

Statement 120 reads the record read by statement
90 and
inputs
data formatted according to statement 160 into the array FORMC.

the

NOTE
If you try to REREAD a record input from
the
teletype,
you will get either the
current
record
or
the
last
150
characters
of
the
current
record,
whichever is the lesser.

10-15

I/O STATEMENTS
10.3

WRITE STATEMENTS

statements transfer data from specified processor storage
locations to peripheral devices.
The various forms of the WRITE
statement enable it to be used in sequential, append,
and random
access transfer modes for formatted, unformatted, list-directed, and
NAMELIST-controlled data transfers.
~RITE

10.3.1

Sequential

For~atted

WRITE Transfers

You may use the following
forms of the
sequential transfer of formatted data:
1.

WRITE

statement

for

the

Form:

WRITE(u,f)list

Use:

Output the values of the
processor
storage
locations
identified
in list into the file
associated with logical unit u.
Convert and
arrange
the
output
data
according to the
specifications ~iven in f.

Ex a:npl e :

WRITE (06,500) OUT (10,20) ,A, B

Form:

WRITE f,list

Use:

Output the values of the
?rocessor
storage
locations identified in list to the default device
(line ?rinter). Convert and arrange the output
data according to the specifications given in f.
WRITE 10,SENO(5,10) ,A,B,C

10.3.2

For.-n:

WRITE f

Use:

Output the contents of any Hollerith
(H)
literal (") field descriptor(s) contained by f
the default device (line printer).
If neither
the foregoing
types of field specifications
found in f, no output transfer is performed.

Exal1l~le:

WRITE 10

or
to
of
is

Sequential Unformatted Binary WRITE Transfer

You ~ay use the following
form of the
sequential transfer of unformatted data:
v'JRITE

WRITE

statements

for

the

(u) list

Use:

Output the values of the
processor
storage
locations
identified
in list into the file
associated with logical unit u.
No conversion or
arrangement of output data is performed.

Example:

itl RI T E ( 1 2) I TAB ( 2 0 , 2 0) , SUM S ( 1 0 , 5 , 2 )

10-16

I/O STATEr-lEN'rS
10.8. 3

S(~guential

List-Directed

~-JRITE

Transfers

You may u!:;e the followi ng fa r In of the vvRI'rE sta temen t
sequential list-directed output transfer.

10.8 .4

in i t i a te

Form:

WRITE(u,*)list

Use:

Output
the values of
the
processor
storage
locations
identified
in
list
into the
file
associated with logical unit u.
The conversion of
each datum
from
internal
to external
form is
performed according
to
the
type of
the
list
variable from which the datum is taken.

Example:

WRITE(12,*)C,X,Y,ITAB(lO,10)

Seguen t i a I NAMELI~ST-<:on_t!"-.?_~}_ ed WRITE__!r a!l~~~ r s

You may use only the following form of the WRITE statement to initiate
a seguential ~AMELIST output transfer.

10.8.5

Form:

~vR IT E ( u , N)

Use:

Out?ut
the values of
the
processor
storage
locations
identified
by the contents of
the
NAMELIST-defineJ list specified by name N into the
file associated with logical unit u.

example:

vvRITE (12 ,NMLST)

Random Access Formatted WRITE Transfers

You may u~;e only the following form of the WRITE statement to initiate
a random access type formatted output transfer:

10.8.6

Form:

WRITE(u#R,f)list

Use:

Output
the values of
the
processor
storage
locations
identified by the contents of list to
record R of
the
file
associated with 109icai
device
u.
Only disk files that have been set up
by either an OPEN
statement or
a
call
to
the
subroutine DEFINE FILE may be accessed by a WRITE
transfer of this form.
The data transferred will
be formatted according to the specifications given
in f.
Only those
records
that
have
been
specifically written are available to be read.

Random Access Unformatted WRITE Transfers

You may use only the following form of the WRITE statement to initiate
a random access unformatted output transfer:
Form:

WRITE(u#R)list

Use:

Output
the
values of
the
processor
storage
locations
identified by the contents of list to
record R of
the
file
associated with logical
10-17

I/O ST\TEMEi\JT3
device unit u. Only disk files that have been set
up by either an OPEN or a call to the DEFINE FILE
subroutine may be accessed by a WRITE transfer of
this form. Only those records that have been
specifically written are available to be read.

10.9

SUMMARY

~"1RITE

STl\TEMENTS

Table 10-3 summarizes the various forms of the WRITE statements.
Table 10-3
Summary of WRI·rE Statements
----·------. - - - - - - ---------.-----.-----.
Type of Transfer

r-_ _ _ _~~---~TTr~a~n~3~f~e~r~M~o~d~e~---.--~

~------~-----.-.------- _~~~_~e n_ t i a 1_________ ._R_a_n_d_o._m_A_c_c_e_s_s_ _

---l

Formatted

WRITE(u,f)list
WRITE f,list
WRITE f

WRITE (u#R, f) li~)t

Unformatted

WRITE(u)list

WRITE(u#R)list

List-Directed

WRITE(u,*)list

NAMELIST-controlled

WRITE(u,N)

~----------------------~----------------~--------------------

Note:

You may include the ERR=c and END=d arguments in
any WRITE statement which has a unit number~
however, they must be last.

~-----------.--------------

10.10

----------_._----------------'

ACCEPT STATEMENT

The ACCEPT statement enables you to input data via either a terminal
keyboard or a batch control file directly into specified processor
storage locations. Use this statement only in the sequential transfer
mode for the formatted transfer of inputs from your terminal keyboard
during program execution.
The following paragraphs describe the
permitted forms of the ACCEPT statement.

10.10.1

Formatted ACCEPT Transfers

Use the following forms of the ACCEPT
transfer of formatted data.
1.

statement

for

the

sequential

Form:

ACCEPT f,list

Use:

Input data character-by-character from the user's
terminal into the processor storage locations
identified by the contents of list.
Format the
input data according to the format specifications
given in f.

Example:

ACCEPT 101,LINE(73)

10-18

I/O STlI.TEr1ENTS
2.

10.10.2

Form:

ACCEP'I' *,list

Use:

Input data charatter-by-character from the user's
terminal
into the processor storage locations
identified by the contents of list.
Convert the
input characters, where necessary, to the type of
its assigned list variable.

Example:

ACCEPT *,IAB,ABE,KAB,MAR

ACCEPT Transfers Into FORMAT Statements

You may US,;? the following form of the ACCEPT statement to i'1put dat.a
from your terminal keyboard directly into a specified FORMAT statement
if the FORi~Al' statement has either or both a Hollerith
(:.-1),
or a
literal
('s')
field descriptor.
If the referenced statelnent has
neither of the foregoing descriptors, the input record is skipped.

10.11

Form:

ACCEP'I' f

U:3e:

Replace the contents of the ap?ropriate fields of
statement f with the data enter2d at the user's
terminal keyboard.

Example:

ACCEPT 101

PRI'-JT STATEMENT

The PRINT 3tatement causes data from specified processor st.orage
locations to be output on the standard output device (line printer).
Use this statement only for
sequential
formatted data transfer
operation; write it in either of the three following forms:
1.

Form:

PRINT f,list

U:;e:

Output the values of the
processor
storage
locations identified by the contents of list to
the line printer. The values output are to be
formatted and arranged according to the format
specifications given in f.
PRINT 55,TABLE(10,20) ,I,J,K

Form:

PRINT *,list

U:3e:

Output the values of the
processor
storage
locations identified by the contents of list to
the line printer. The conversion of each datum
from
internal to external form is performed
according to the type of the list variable from
which the datum is taken.

Example:

PRINT *,C,X,Y,ITAB(lO,lO)

Form:

PRINT f

U:3e:

Output the contents of the FORMAT
statement.
Hollerith
(g) or literal field descriotors to the
line printer.
If neither an H nor a literal field
10-19

I/O STA'rEr1ENTS
descriptor
is present in the referenced FORMAT
statement, no operation is performed.
PRINT 55
second form of the PRINT statement is particularly useful when
employed with ACCEPT f statements to cause desired data (comments or
headings) to be inserted into reports at program execution time.

'r~e

Example
Tne sequence
55

FORMAT(' END OF ROUTINE')

PRl;\lT S 5
results in the printing of the phrase

"END OF ROUTINE'!

the

line

!:)[ inter.

10.12

PUNCrl STATEMENT

The PUNCH statement causes data from specified processor storage
locations to be out?ut to the system standard paper tape punch. Use
this state~ent only for sequential formatted data transfers~
write it
in one of tne three following forms:
1.

PorlU:

PUNCH f,list

Use:

Output the values of the
processor
storage
locations identified by the contents of list to
the standard paper tape punch unit.
The values
output are to be formatted and arranged according
to the format specifications given in f.

Example:

PUNCH 10,TABLE(10,20) ,I,J,K

Form:

PUNCH *,list

use:

Output the values of the
processor
storage
locations identified by the contents of list to
the paper tape punch unit. The conversion of each
datum [rom internal to external form is performed
according to the type of the list variable from
which the datum is taken.
PUNCH *,I,A,B,M,TAB(5,10)
PUNCH f

Use:

Output the contents of the referenced FORMAT
statement
Hollerith
(H)
or
literal
field
descriptors to the standard paper tape punch unit.
If neither an H nor a literal field descriptor is
present in the referenced FORMAT statement, no
operation is performed.

rhe third form of the PUNCd statement is particularly useful when
in
conjunction with an ACCEPT f statement
to cause
user-entered data (comments or headings) to be added to an output file
3t program execution time.

e~ployej

10-20

I/O
10.13

ST_~TEMENTS

TYPE STATEMENT

The TYPE statement causes data from specified processor storage
locations to be output to your (control) terminal printing or display
device.
Use this statement only for sequential formatted data
transfers~
write it in one of the following forms:
TYPE f,list

10.14

Use:

Output the values of the
processor
storage
locations identified by the contents of list to
the user's terminal. The values output are to be
formatted according to the format specifications
given in f.

Example:

TYPE 101,TABLE(lO,20)I,J,K

Form:

TYPE f

[se:

Output the contents of the referenced FORMAT
statement
Hollerith
(H)
or
literal
field
descriptors to the user's terminal device.
If the
referenced
FORMAT statement does not contain
either an H or a literal field descriptor, no
operation is performed.

Example:

TYPE 101

Form:

TYPE *,list

Use:

Output the values of the
processor
storage
locations identified by the contents of list to
the user's terminal. The conversion of each datum
from
internal to external form is performed
according to the type of the list variable from
which the datum is taken.

Example:

TYPE * ,IAB(1,5) ,1\,B

FIND STATEMENT

The FI~D statement does not initiate a data transfer operation~
use
it during random access read operations to locate the next record to
be read while the current record is being input. The program does not
hav,e access to the "foundl! record until the next READ statement is
executed.
The form of the FIND statement is
FIND (u#R)
Example:
In the sequence
READ(Ol~90)

FIND(Ol#lOl)

READ(Ol#lOl)
10-21

I/O S'1'.1\TEMENTS
the FIND statement will locate record #101 on device 01 after record
90 has been retrieved.
Record #101 is not processed until the second
READ statement in the sequence is executed.

10.15

ENCODE

A~D

DECODE

STATEME~TS

Use the ENCODE and DECODE statements to perform sequential formatted
data transfer between two defined areas of processor storage, i.e., an
I/O list and a user-defined buffer~
no peripheral I/O device is
involved in the operations performed by these statements.
The ENCODE statement transfers data from the variables of a specified
I/O list into a specified storage area.
ENCODE operations are similar
to those performed by a WRITE statement.
The DECODE statement transfers data from a specified storage area into
the processor storage locations identified by the variables of an I/O
list. DECODE operations are similar to those performed by a READ
statement.
write the ENCODE and DECODE statements in the following forms:
ENCODE(C,f,s)list
DECODE(c,f,s)list
where
c specifies the number of characters to be in each internal
storage area.
This argument may be an integer, an integer
expression, or either a real or double precision expression that
is converted to an integer form.
NOTE
5 characters per storage location are stored in the
buffer without regard to the type of variable given as
the starting location.
f specifies either a FORMAT statement or an array
format specifications.

that

contains

s specifies the address of the first storage location that is to
be used in the transfer operations. When multiple records are
specified by the format being used, the succeeding records follow
each other in order of increasing storage addresses.
list specifies an

I/O

list

the

standard

form

(Paragraph

10.3.4) .

When multiple records are stor'c,J by ENCODE, each new record starts on
a new storage location boundary rather than there being a CRLF
inserted between records.

10-22

I/O STA.TEMENTS
10.lS.1

ENCODE Statement

A description of the form and use of the ENCODE statement follows:
Form:

ENCODE(c,f,s)list

Use:

The values of the processor
storage
locations
identified by the contents of list are converted
to ASCII character strings according to the format
specifications
given
in
f.
The converted
characters are then written into
the destination
area starting at
location s.
If you
try to
transfer more characters than the
soecified area
can contain, the excess characters a~e ignored.
If you transfer fewer
characters
than
specified
for the record size, the empty character locations
are filled with blanks.

Example:

10.lS.2

ENCODE(SOO,lOI ,START) TABLE

DECODE Statement

A description of the form and use of the DECODE statement follows:
Form:

DECODE(c,f,s)list

Use:

The character
strings are
taken
starting
at
location s,
converted (decodej) according to the
format specifications given in f,
and
stored
as
the
values of
the
processor
storage locations
identified in list.
If
the
format
specification
requires
more
characters
from a record than are specified by c,
the extra characters are assumed to be blanks.
If
fewer
characters are required from a record than
are specified by c,
the extra characters are
ignored.

10.15.3

Example:

DECODE(SO,SO,START)GET(S,lO)

Example Of

ENCODE/D~C??E

Operations

The following program illustrates the
DECODE statements:

use

both

Exa.mple
Assume the contents of the variables to be as follows:
A(l)
A(2)
J
B
C

contains the floating point number 300.45
contains the floating point number 3.0
is an integer variable
is a 4-word array of indeterminate contents
contains the ASCII string 12345

DO 2 J=1,2
ENCODE(16,10,B)J,A(J)
FORMAT(lX,2HA(,Il,4H)

(1)
( 2}
( 3}

,F'8,2

10-2:3

the

ENCODE

and

I/O STA'rEMENTS
(4 )
(5)
(5)
( 7)
(8)
(9)

(10)
( 11)

11
2

12
13

'I'YPE 11,B
FORt'lAT (4A5)
CONTINUE
DECODE(5,12,C)B
FORMAT(3F1.0,lX,Fl.0)
TYPE 13,B
FORMAT(4F5.2}
END

Array B can contain 20 ASCII characters.
The
result of
statement after the first iteration of the uO loop is:
B (1)

B (2)
8 (3)
B(4)

'A (1)
,=

Typed at line 4 as

'300.4' ,
,5

A (1)

300.45

The result after the second iteration is:
3 (1)
B (2)
B (3)
B (4)

, A (2)

Typed at line 4 as

'=
, 3.0

A(2)

3.0

The DECODE statement:
1.

Extracts the digits 1, 2, and 3 from C

Converts them to floating point values

Stores them in B(l), B(2}, and B(3)

Skips the next character

Extracts the digit 5 from C

Converts it to a floating-point value, and,

Stores it in B(4)

(the digit 4)

The output from the TYPE statement at line 9 is:
1.00 2.00 3.00 4.00 5.00

10-24

the

ENCODE

I/O ST1\TEMENTS

10.16

SUMMARY OF I/O STATEMENTS

Table 10·-4 on pages 10-26 and 10-27 presents
pE~rmitted forms of the FORTRAN-IO I/O statement.

10-25

summary

all

Ta.ble 10-4
Su;';,'T'ary of FOE'I'RA.tJ-1C I/O Statements

I
I
I

I/O Statements

ForGatted

Transfer ForfTIat Control
Namelist
Unformatted
I

List-Directed

READ *,list

READ f,list
READ f
Random
wRITE
Sequential or
Append(l)

READ (u#R,f)list
'0)f;'I TE
~~T I T E
W~ITf

f--'
0

(u,f)list
f, 1 i s t
f

READ(u#R)list
V-iRITE(u)list

WRITE(u,*)list

~)RITE(u,N)

""--.

Random (2)

WRITE (u#R,f)list

t-3

WRITE (u#R)list

:;po

I
tv
C'I

t-3

REREAD
Sequential

(T)

:s:
t'1
z

REREAD f,list

t-3

FIND
Random-only

FIND (u#R)

ACCEPT
Sequential only

ACCEPT f,list

FIND (u#R)

I
I

ACCEPT f

J
1. You must use an OPEN statement to set up an append mode.
2. You must use either the OPEN statement or a call
FILE subroutine to set up a
random access mode.

the

DEFINE

ACCEPT *,list

Table 10-4 (Cont.)
Surnary of FORTRAN-IO I/O Statements

1-I

I/O Statements

--Ir-------

PRINT
Sequential only

For~atted

Transfer Format Control
Unformatted
Namelist

List-Direction

PRINT f,list
PRINT f

PRI~1T

*,list

PC~CE f,list
PL'NCH f

PUNCH *,list

PUL~CH

Sequential only

'-....

!-'

TYFE
Sequential only

I
N
-..J

'I'YPE [,list
TYPE f

TYPE *,list

o
en
~

P
r-3

tTl

Et~CODE

tTl

Sequential only

ENCODE (c,f,s)list

DECOGE
Sequential only

DECODE (c,f,s)list

~
(fl

Legend:
u
f

list
£~

logical unit

nu~ber

s tat er~e n t n UT'1 be ref fOHt·ll\'I'
s~ate~ent or na~e of array
containino for~at infor~ation
IIC list
name of specific NAMELIST
l/C list

c
s

symbol used to specify list-directed I/O
o?erator
variable which specifies lOjical record
position
number of characters oer internal record
adcress of the first storage location to
be used

CHAPTER 11
NAMELIST STATEMENTS

11.1

INTRODUCTION

Use the NAMELIST statement to define I/O lists similar to those
described
in Chapter 10 (Paragraph 10.3.4).
Reference defined
NAMELIST I/O lists in special forms of the READ and WRITE statements
to provide a method of transferring and converting data without
referencing format specifications or specifying an I/O list in the I/O
statement.

11.2

NAMELIST STATEMENT

wri.te NAMELIST statements in the following form:
NAMELIST/Nl/Al,A2, ... ,An/N2/Bl,B2, ... ,Bn/Nn/ •..
where
/Nl/ through /Nn/

represents names of
Always enclose the

individual lists.
name with slashes

(/N/)

Al through An
and
Bl through Bn

are the items of the lists identified,
respectively, by names Nl and N2. A
list may contain one or more variable,
array, or array element names. Delimit
the items of a list by commas.
Each
list
of
a
NAMELIST
statement is
identified (and referenced) by the name
immediately preceding the list.

Example
DIMENSION C(2,4)
NAMELIST/TABLE/A,B,C/SUMS/TOTAL
In the foregoing example, the name TABLE identifies the
list
A,B,C(2,4), and the name SUMS identifies the list consisting of the
array TOTl\L.
Once a list has been defined in a NAMELIST statement, one or more
sti3ltement~:; may reference its name.

11-1

I/O

~AMELIST

STATEMENTS

The rules for structuring a NAMELIST statement are:
1.

You may use a maximum of six characters for a NAMELIST name.

You must begin it with an alphabetic character.

You must enclose it in slashes.

The NAMELIST name must precede the list of entries
it refers.

The NAMELIST name must be unique within the program.

You may define a NAMELIST name only once, and you must define
it by a NAMELIST statement. Once defined, you may use a name
only in READ or WRITE statements.

You must define the NAMELIST name
statement in which it is used.

You cannot use a variable used in a NAMELIST statement
dUillmy ar]Uillent in a SUBROUTINE definition.

You must define any dimensioned variable contained in a
NAMELIST
statement
in
an array declaration statement
preceding the NAMELIST statement.

11.2.1

advance

which

the

I/O
as

NAMELIST-Controlled Input Transfers

During input (READ) transfer operations in which a NAMELIST-defined
name is referenced, the records are read until a record is found that
begins with the sequence I $1 (a space followed by a dollar sign)
followed by the referenced name. The dollar sign must be the second
character in the record;
the first character in the record must be a
blank.
Once the proper symbol-name combination is found, the data
items following it are transferred on a one-to-one basis to the
processor
storage lccations identified by the contents of the
referenced list. The input data is always converted to the type of
the list variable when there is a conflict of types.
The input
operation continues until another $ symbol is detected.
If variables
appear in the ~AMELIST record that do not appear in the NAMELIST list,
an error condition will occur. Data items of records to be input
(read)
using NAMELIST-defined lists must be separated by com~as and
may be of the following form:
V=Kl,K2, ... ,Kn
where
1.

V may be a variable, array, or array element name.

Kl through Kn are constants of type integer,
real, double
precision, complex (written as (A,B) where A and B are real),
or logical (written as T for true or F for false).
A series
of identical constants may be represented as a single
constant preceded by a repetition factor
(5*5 represents
5,5,5,5,5) .

11-2

NAMELIST STATEMENTS
In transfers of this type,
logical and complex constants must be
equated to variables of their own type. Other type constants (real,
double-precision, and integer) may be equated to any other type of
variable
(except logical or complex), and will be converted to the
variable type.
For example, assume A is a 2-dimensional real array, E
is a I-dimensional integer array, C is an integer variable, and thai
the input data is as follows:
$FRED A(7,2)=4, 8=3,6*2.8, C=3.32$
A READ statement referring to the NAMELIST defined name FRED will
result in the following:
The integer 4 will be converted to floating
poi::1t and placed in A (7,2). The integer 3 will be placed in B (1), and
the integer 2 (converted) will be placed in I3(2) ,8(3), ... ,B(7). The
floating point number 3.32 will be converted to the integer
3 and
placed in C.
NOTE
,I & II
rn a y be use d i n s tea d
NAMELIST-controlled input.

11.2.2

NAMELIST-Controll~d

0 f

.. $ ..

Output Transfers

When a WRITE statement refers to a NAMELIST-defined name,
all
variables and arrays and their values belonging to the named list are
written out, each according to its type.
Arrays are written out by
columns.
Output data is written so that:
1.

The fields for the data will be large enough to
the significant digits.

The output can be read by an input
NAMELIST- defined list.

statement

contain

all

referencing

For example, if JOE is a 2 X 3 real array, the statement
NAMELIST/NAMl/JOE,Kl,ALPHA
WRITE (u,NAMl)
generates the following form of output:

Column

$Nl\MEl
JOE= -6.750000

,
0.2340000E-04,
-1970000.
Kl=
O.OOOOOOOE-Ol,
, $
ALPHA=
3.000000

680.0000
73.10000

NOTE:
Do not use dovice positioning commands
such as BACKSeACE, SKIP, RECORD, etc.,
with NAMELIST-controlled I/O operations.
If
you
do,
the
results
are
unpredictable.
11-3

-17.80000

CHAPTEf<~

FILE CONTROL STATEMENTS

12.1

INTRODUCTION

This chapter describes the OPEN and CLOSE statements.
They are file control statements used to set up files and establish
parameters for I/O operations and to terminate I/O operations.

12.2

OPEN AND CLOSE STATEMENTS

Both the OPEN and CLOSE statements are unique to FORTRAN-lO;
they
both use the same format and have the same options and arguments.
The OPEN statement enables you to define all of the important aspects
of each desired data transfer operation;
it provides an extensive
list of required and optional arguments that define in detail:
1.

the name and location of the data file

the type of access required

the data format within the file

the protection code{l) to be assigned an output data file

the disposition of the data file

data file record, block and file sizes

a data file version identifier

In addition, a DIALOG argument is provided that permits you to
establish a dialogue mode of operation when the OPEN statement
containing it is executed.
In a
dialogue
mode,
interactive
terminal/program communication is established. This enables you to
define, redefine, or defer the values of the optional arguments
contained by the current OPEN statement during program execution.
The general form of the OPEN statement is:
OPEN(Argl,Arg2, ... ,Argn)

1. Refer to Chapter 8 of the DECsystem-lO Monitor Calls Manual,
DEC-lO-OMCMA-B-DN3, for a description of file access protection codes.

12-1

FILE CONTROL STATEMENTS
Use the CLOSE statement in the termination of an I/O operation to
dissociate the I/O device being used from the active file and
file-related infor~ation, and to restore the core occupied by I/O
buffers and other transfer-related operations. All required device
dependent termination functions are also performed on the execution of
a CLOSE statement. Note that the CLOSE statement can change the name,
protection, directory, and disposition of the file being closed.
Once a CLOS8 statement has been executed, you must
statement to regain access to the closed file.

use

anothE!r

OPEN

The general form of the CLOSE statement is:
CLOS E (,!u 9 1 . ,A r 9 2 . , •.. ,A. r 9 n)
CAUTION
If you usc a filename argument in a
CLOSE statement that is different from
the current filename, the file will be
renamed.

12.2.1

Options for OPEN and CLOSE Statements

The options and their arguments, which you may use in
and CLOSE statements, are:
1.

UN IT

both

the

OPEN

This option is required;
it defines the
FORTRAN I/O unit number to be used. FORTRAN
devices are identified by assigned decimal
numbers within the range 1-63; however, UNIT
may be assigned an integer variable
or
constant.
The general form qf this argument
is:
An integer variable or constant

UNIT=
NOTE

FORTRAN-IO
standard
logical
unit
assignments are described in Chapter 10
(Table 10-1). The range, i.e., 1-63, of
the
possible
UNIT
numbers
is an
installation-defined parameter.
2.

DEVICE

This option may specify either the phys~cal
or
the logical name of the I/O device
inVOlved.
(A logical name always
takes
precedence over a physical name.) The DEVICE
arguments may specify I/O devices located at
remote stations, as well as logical devices.
The general form of the DEVICE argument is:
DEVICE=

12-2

A literal constant or variable

FILE CONTROL STATEMENTS
If you omit this option, the logical name u
(where u is the decimal
unit number) is
tried;
if this
is
not successful,
the
standard (default) device is attempted.
3.

ACCESS

ACCESS describes the
type of
input and/or
output statements and the file access mode to
be used
in a
specified
data
transfer
operation.
You may assign ACCESS anyone of
six possible names, each of which specifies a
specific
type
of
I/O
operation.
The
assignable names and the operations specified
are:
a.

SEQIN

The specified data file
is
to be
read
in sequential
access mode.

SEQOUT

The specified data file
to
be
written
in
sequential access mode.

SEQINOUT

The specified data file may
be first read, then written
(READ/WRITE
sequence)
record-by-record
in
a
sequential
access
mode.
When you specify SEQINOUT, a
WRITE/READ
sequence
is
illegal.
If no access is
specified,
SEQINOUT
is
assumed.

RANDOM

The specified data file
may
be either
read or written
into, one record at a
time.
In a
random access mode of
operation,
the
relative
position of each record is
independent of the previous
READ
or WRITE statement;
all
records accessed must
have a fixed logical record
length.
The RECORD
SIZE
option
is
required
for
random access
operations.
You
must specify a disk
device
when
the
random
argument is used.

RANDIN

This argument enables you to
establish
a
special,
read-only random access mode
with a named file.
During a
RANDIN mode,
you may read
the
named
file
simultaneously with
other
users
who
have
also
established a
RANOIN mode
and with the owner of the
file.
The use of RANDIN
enables a data base to be
shared by more than one user
at the same time.

12-3

is
a

FILE CONTROL STATEMENTS
f.

APPEND

The record specified by a
corresponding
WRITE
statement is to be added to
the logical end of a named
file. You must close and
then
reopen the modified
file to permit it to be
read.
The general form of
ACCESS argument is:

the

'SEQIN'
'SEQOUT'
'SEQINOUT'
,Z\CCESS= 'RANDOM'
'RANDIN'
'APPEND'
variable (set to
literal)
4.

MODE

This option defines the character set of an
external file or record.
The use of this
argument is optional;
if you do not use it,
one of the following is assumed:

a.
b.

ASCII for a formatted I/O file transfer
Binary for an unformatted
I/O
file
transfer.
NOTE

Refer to the DECsystem-IO Monitor Calls
Manual for a detailed description of the
data modes given in the following list.
You must use one of the following character
set specifications with the MODE argument:
Literal

Action Indicated

'ASCII'

Specifies an ASCII character set.

'BINARY' Specifies data
formatted
FORTRAN binary data file.

'IMAGE'

Specifies an image (I) mode data
transfer for the associated READ or
WRITE statements.
IMAGE
is
an
unformatted binary mode.

'DUMP'

The data file to be
to be handled in
operation.

transferred is
a DUMP mode of

The general form of the MODE argument is:
'ASCII'
'BINARY'
'IMAGE'
'DUMP'
variable (set to literal)

MODE=

12-4

FILE CONTROL STATEMENTS
5.

DISPOSE

This option specifies an action to be taken
regarding a file at close time. When used,
DISPOSE must be either a variable or one of
the following literals:
Literal
'SAVE'

Action Indicated
Leave the file on the device.

'DELETE' If the device involved is either a
DECtape or disk, remove the file;
otherwise, take no action.
'PRINT'

If the file is on disk, queue it for
printing;
otherwise,
take
no
action.

'LIST'

If the file is on disk, queue it for
printing
and
delete
the file;
otherwise take no action.

'PUNCH'

Paper tape punch output.

'RENAME' Change filename.
(This is redundant
if a new filename is given.)
If the DISPOSE argument is not given,
argument DISPOSE
'SAVE' is assumed.
general form of th~ DISPOSE argument is:

DISPOSE=
~

PILE

the
The

'SAVE'
'DELETE'
'PRINT'
'LIST'
'PUNCH'
'RENAME'
variable (set to literal)

This option specifies the name of the file
involved in the data transfer operation.
FILE
must
be
either
a
literal,
double-precision,
comolex,
or
single-precision variable.
Single-precision
variables are assumed to contain a 1- to
5-character
file
specification;
double-precision
variables
permit
10-character file specification. The format
is a 1- to 6-character filename optionally
followed by a period and a 0- to 3-character
extension.
Any excess characters in either
the name or extension are ignored.
If you
omit the period and extension, the extension
.DAT is assumed;
if just the extension is
omitted, a null extension is assumed. So if
you want a filename without an extension,
remember to use the period.
If a filename is not specified or is zero, a
default name is generated that has the form
FORxx.DAT
where xx is the FORTRAN logical unit number
(decimal) or is the logical unit name for the
12-5

FILE CONTROL STATEMENTS
default statements ACCEPT, PRINT,
PUNCH,
READ, or TYPE.
The general form of a FILE
argument is:
A literal or variable set to a
literal

FILE=
7.

PROTECTION

This option specifies a protection code to be
assigned the data file being transferred.
The protection code determines the level of
access
to the file that three possible
classes of users (owner, member, or other)
will have. PROTECTION may be a 3-digit octal
literal or a variable~
if the argument is
assigned a zero value or is not given, the
default protection code established for the
DECsystem-lO
installation
is used.
The
general form of the PROTECTION argument is:
PROTECTION= 3-digit octal
constant
integer variable

DIRECTORY

Use this option for disk files only.
It
specifies the location of the user file
directory (UFu)
or the sub-file directory
(SFD) that contains the file specified in the
OPEN statement. A directory identifier may
consist of either:
a. Your project
programmer
number
that
identifies the UFD, for example, 10,7, or
b. A UFD/SFD directory path specification. .A
path specification lists the UFD and the
names of its SFDs that form a path to the
desired SFD.
For example, the following
path specification identifies the path
leading to SFD 1234:
10,7,SFDA,SFDB,1234

NOTE
Refer to the DECsystem-lO Monitor Calls
Manual for a complete description of
directories and multilevel
directory
structures.

The general form of a DIRECTORY argument is:
DIRECTORY=

Literal
or
array
directory
containing
specification

name
path

You may also establish an array containing
the directory specification as its elements
and reference the array in the DIRECTORY
argument.
Single-precision arrays permit
5-character directory names to be
used~
double-precision arrays permit 6-character
12-6

FILE CONTROL STATEMENTS
( 0)
names to be used. You must use a zero
entry
to
terminate
a
directory
path
specification given in an array.

Examples of
the
use
of
singleand
double-precision arrays in an OPEN statement
DIRECTORY specification follow:
a. Single-Precision Array
OPEN (UNIT

5, DIRECTORY = PATH, ... )

where PATH and its elements are:
DIMENSION PATH (5)
PATH (1)= "10 ! (PROJECT NUMBER)
PATH (2)="7
! (PROGRAMMER NUMBER) UFD
PATH (3)='SFDA'
Names of sub-file
PATH (4)='SFDB'
directories (SFD's)
PATH (5)=0
b.

Double-Precision Array
OPEN (UNIT=5, DIRECTORY = PATH, ..• )
where PATH and its elements are:
DOUBLE PRECISION PATH (5)
PATH (1)="000000000010000000000007
! (PROJ.,PROG. NUMBERS=UFD)
PATH
PATH
PATH
PATH

(2)='SFDABC'
(3)='MYAREA'
(4)='YOURIT'
(5)=0

!names of sub-file
!directories (SFDs)

The elements of a directory specification
may then be either a literal or a singleor double-precision array.
The following is
specification:

example

literal

DIRECTORY='10,7,SFDl,SFD2,SFD3'
.~'-

Project
Programmer
Number

,/
Sub-File

Directory
Path

Whenever the specification is an array, you
may
specify
the
required
project and
programmer numbers either of two ways.
You
can use one word with the project number in
the left half and the programmer number
in
the right half, or, use the right halves of
separate sequential word locations.

12-7

FILE CONTROL STATEMENTS
9.

BUFFER COUNT

This option enables you to specify the number
of I/O buffers to be assigned to a particular
device. If this argument is not given or is
assigned a value of zero, the Monitor default
is assumed.
The general form
of
this
arg~ment is:
BUFFER

10.

FILE SIZE

COUNT=

VERSION

BLOCK SIZE

An
integer
variable

RECORD SIZE

constant

An octal constant
variable

integer

You can use this option for all storage media
except disk and DECtape. It enables you to
specify a physical storage block size for
devices other than disk or DECtape. The
value assigned the BLOCK SIZE arguments may
be an integer constant or variable. The size
specified must be greater than or equal to 3
and less than or equal to 4095. The general
form of this argument is:
BLOCK SIZE= An
integer
variable

13.

Use this option for disk operations only;
it
enables
you to assign a l2-digit octal
version number to a file when it is output.
The quantity assigned to the VERSION argument
may be either an octal constant or variable.
The general form of the argument is:
VERSION=

12.

constant

Use this option for disk operations only;
it
enables you to estimate the number of words
that an output file is going to contain. The
use of FILE SIZE enables you to ensure at the
start of a program that enough space is
available for its execution.
If the size
specified is found to be too small during
program executions, the Monitor allocates
additional space according to the normal
Monitor algorithms.
The value assigned to
the FILE SIZE arguments may be an integer
constant or variable and will be rounded up
to the next higher block boundary (multiple
of 200 octal).
The general form of this
argument is:
FILE SIZE=

11.

An integer
variable

constant

This option enables you to force all logical
records to be a specified length.
If a
logical record exceeds the specified length,
it is truncated;
if a logical record is less
than the specified size, nulls are added to
pad the record to its full size. The RECORD
SIZE argument is required whenever a random
access mode is specified. The value assigned
to this argument may be either an integer
constant or variable, and may be expressed as

12-8

FILE CONTROL STAT8MENTS
the number of words or characters,
depending
on the mode of the file being described.
The
general form of this argument is:
RECORD
14.

hSSOCIATE
VARIABLE

SIZE=

An
integer
variable

constant

Use
this
option
for
disk
random
access
operations only.
It provides storage for the
number of the record to be accessed
next
if
the
program being executed were to continue
to sequentially access records starting
from
the current
READ.
For
example, if record
number 3 were read,
the ASSOCIATE VARIABLE
would
be equal
to
4. The general form of
this argument is:
ASSOCIATE VARIABLE = Integer variable

15.

PARITY

Use this option for magnetic tape
operations
only;
it permits you to specify the type of
parity to be observed (odd or
even)
during
the
transfer
of data.
The general form of
this option is:
PARITY=

16.

DENSITY

'ODD'
'EVEN'
variable

(set to literal)

Use this option for magnetic tape
operations
only;
it permits you to specify any of four
possible bit-per-inch
(bpi)
tape
density
parameters
for
magnetic
tape
transfer
operations.
The general form of this option
is:

'200'
DENSITY=

'556'

'800'
'1600'
variable
17.
"

DIALOG

(set to literal)

The use of this option in an OPEN statement
enables
you
to
supersede or defer,
at
execution
time,
the
values
previously
assigned
to
the arguments of the statement.
There are two forms of
this
argument.
The
first is:
DIALOG
This form establishes a
dialogue with your
terminal when the OPEN statement is executed.
FOROTS outputs the following messages at
the
user's terminal.
UNIT=n:/ACCESS=SEQINOUT/MODE=ASCII
ENTER NEW FILE SPECS.
END WITH A $

(ALT)

Once
the
message
and
defined
file
specification are output, you may enter any
desired changes.
You
need
enter
only the
arguments that are to be changed.

12-9

FILE CONTROL STATEMENTS
The second form of the argument is:
DIALOG=

Literal or array

The value assigned to DIALOG may be a literal
or an array containing a file specification
with the desired information.
18.

ERR

The use of this option in an OPEN or CLOSE
statement enables you to transfer program
control to an executable statement when an
error
is detected during the processing of
the OPEN or CLOSE statement.
The general
form of this option is:
ERR= s
where s
is the statement label
of
an
executable statement
(that appears
in the
same program unit as the error specifier)
to
which program control is transferred when an
error is detected.
Associated with the ERR= option on OPEN/CLOSE
is the subroutine ERRSNS that enables you to
pinpoint the error.
See Appendix H for
FOROTS error values returned by ERRSNS.

Examples:
OPEN (UNIT= 1, DEVICE= 'DSK', ACCESS= 'SEQIN', MODE= 'BINARY')
causes a disk file
named FOROl.DAT
(since no FILE= option was
specified) to be opened on unit 1 for sequential input in binary mode.
OPEN (UNIT= 3, DEVICE= 'DSK', FILE= 'PAYROL.DAT',
1
ACCESS= 'RANDOM', MODE= 'ASCII', RECORD SIZE= 80,
2
ASSOCIATE VARIABLE= I, ERR= 240)
causes a disk file named PAYROL.DAT to be opened on unit 3 for
random
input/output operations in ASCII mode.
The records in PAYROL.DAT are
80 characters long;
the ASSOCIATE VARIABLE for this file is I.
If an
error occurs during the execution of this OPEN statement, the OPEN
will terminate and control will transfer to the statement labeled 240.
CLOSE (UNIT= 3, DISPOSE= 'DELETE')
causes the file on unit 3 to be closed and removed if the file
DEC tape or disk.

12.2.2

Summary of OPEN/CLOSE Statement Options

Table 12-1 summarizes the options permitted and required in the
and CLOSE statements and the type of value required by each.

12-10

OPEN

FILE CONTROL STATEMENTS
Table 12-1
OPEN/CLOSE Statement Arguments

...-------.;.--------,-----------_._-----------_._._.- -- ---- -.- ---.Argument

possible Value

Open*

Close*

t---------------+---------------------.-----.-. -- -_.

ACCESS=
ASSOCIATE VARIABLE=
BLOCK SIZE=
BUFFER COlJNT=
DENSITY=
DEVICE=
DIALOG=
DIRECTORY=
DISPOSE=
ERR=
FILE=
FILE SIZE=
MODE=
PARITY=
PROTEC'TION=
RECORD SIZE=
UNIT=
VERSION=

'SEQIN', 'SEQOUT', 'SEQINOUT',
'RANDIN', 'RANDOM', 'APPEND',
or variable
Integer variable
Integer constant or variable
Integer constant or variable
Literal constant or variable
Literal constant or variable
Literal or array or none
Literal or variable or array
Literal constant or variable
Statement Number
Literal constant or variable
Integer constant or variable
Literal constant or variable
Literal constant or variable
An octal constant or
integer variable
Integer constant or integer
variable
Integer variable or constant
Octal constant or variable

.R = Required
o = Optional
I = Ignored

12-11

o
o
o
o
a
o

I
I
I
I
I
I

a
a

o
a

a
a
a
a
a

I
I
I

CHAPTEH 13
FORMAT STATEMENT

13.1

INTRODUCTION

Use FORMAT statements
in conjunction with
the
I/O list of
I/O
statements during
formatted data
transfer operations.
The FORMAT
statements contain field descriptors
that,
together
with
the list
items of associated I/O statements, specify the forms of the data and
data fields that comprise each record.
FORMAT statements may appear almost anywhere in a
FORTRAN-IO
source
program.
The only placement
restrictions are
that
they follow
PROGRAM, FUNCTION, SUBPROGRAM, or BLOCK DATA statements;
and
that
they precede the END statement.
(Refer to Section 2.4.)
You must label FORMAT statements so that I/O statements can
them •

.
'

13.1.1

reference

FORMAT Statement, General Form

The general form of a FORMAT statement follows:
k FORMAT(SAl,SA2, ..• ,SAn/SBl,SB2, ..• ,SBn/ ... )
where

.
'

= the required statement label

SAl through SAn
and
SBI through SBn

(which
be referenced by I/O statements) .

can

only

individual field descriptor sets

In the focegoing statement form, the individual field descriptors
are
delimited by commas
(,).
Field descriptor
sets and records are
delimited by slashes (/).
For example,
a
FORMAT statement of
the
form:
FORMAT(SA1,SA2/SBl,SB2/SCl,SC2)
contains format specifications for
three
containinq two field descriptor sets.

records

with

each

record

Adjacent slashes (//) in a FORMAT statement specify that a
record
is
to be skipped during
input or is to consist of an empty record on
output.
For example, a FORMAT statement of the form:
FORMAT(SAl,SA2///SBl,SB2)

13-1

FORMAT STATEMENT
specifies four records are to be processed;
third records are to be skipped.

however, the

second

and

You may represent
repeated
field
descri?tors or
groups of
field
descriptors by uS1ng
a
repeat
form.
Indicate the repetition of a
single field descriptor by preceding the descriptor
with
an
integer
constant
that
specifies how many times
the descriptor
is to be
repeated.
For example, a FORMAT statement of the form:
FORMAT(SAI,SA2~SA3,SA1~SA2,SA3,SA1,SA2,SA3)

may be written as
FORMAT(3(SA1,SA2,SA3))
You may nest the repeat forms of field descriptors to any depth.
example, a FORMAT statement of the form:

For

FORMAT(SA1,SA2,SA2,SA3,SA1,SA2,SA2,SA3)
may also be written in the form:
FORMAT(2(SAI,2SA2,SA3))
The following paragraphs discuss the manner in which you may
foregoing
statement
forms
and
the effect each has on
involved.

13.2

use
the
the data

FORMAT DESCRIPTORS

FORMAT statement descriptors describe
the
record
structure of
the
data,
the
format
of
fields
within the record, and the conversion,
scaling, and editing of data within specific
fields.
The
following
descriptors can be used with FORTRAN-IO:
Descriptors
rFw.d
rEw.d
rDw.d
rGw.d

}

Comments
Floating point numeric field descriptors

rIw

Integer field descriptor

rLw

Logical field descriptor

kHs
'text'

}
}

rX
Tw

}

rAw
rRw

Alphanumeric data field descriptor
Alphanumeric data in a FORMAT statement field
descriptor
Field formatting descriptors

Numerical scale factor descriptor

Record delimiter

Carriage return suppression for terminal

rOw

Octal field descriptor
13-2

FORMAT STA'rEMENT
where
r

an optional unsigned integer representing a repeat count.
This option enables a field descriptor to be repeated r
times.

an optional integer constant representing the width (total
number of characters contained) of the external form of
the field being described.
All characters,
including
digits, decimal points, signs, and blanks that are to
comprise the external form of the field, must be included
in the value of w .

an optional unsigned integer specifying the number of
fractional digits that are to appear in the external
representation of the field being described. Note that w
~ust be specified if'.d is included in the descriptor.

an unsigned integer specifying the number of characters to
be processed during the transfer of alphanumeric data.

represents a string of ASCII (alphanumeric) characters.

a signed integer constant (plus signs are optional) .

The characters A, D, E, F, G, H, I, L, 0, P, and R indicate the manner
of conversion and editing to be performed between the internal
(processor) and external representations of the data within a specific
field;
th~se
characters are referred to as conversion codes. Table
13-1 gives the FORTRAN-IO conversion codes and a brief description of
the function of each.
'rable 13-1
FORTRAN-IO Conversion Codes
r------------,--------------------

Function

Code

;-------+---------------------------

Transfer alphanumeric data
Transfer real data with a D exponent(l)
Transfer real data with an E exponent(l)
Transfer real data without an exponent
Transfer integer, real, complex, or logical data
Transfer literal data
Transfer integer data
Transfer logical data
Transfer octal data
Numerical scaling factor
Transfer alphanumeric data

A
D

E
F
G
H
I
L

o
P

------~--------

1. An exponent of 0 is assumed if none is given.

The use of commas to delineate format descriptors within a format
For
specification is optional as long as no ambiguity exists.
example,
FORMl~T

(3X, A2)

can be written as
FORMl\T (3XA2)
13-3

FORMAT STATEMENT
Since interpretation of a format specification
the specification

left

associative,

rORMAT(I22,I5)
=an be written as
FORMAr(I2215)
However, a comma is required when you wish to specify
FOHMAT(I2,2I5)
The following paragraphs provide detailed descriptions of the
various
types
of format descriptors, the manner in which they are written and
employed, and their use in FORMAT statements.

13.2.1

Numeric Field Descriptors

The forms of the field descriptors used
conversion of numeric data follow.
Description
Dw.d
Ew.d
Ew.d,Ew.d
Fw.d
Fw.d,Fw.d
Iw
Ow
Gw.d
Gw
Gw.d,Gw.d

specify

the

format

and

Type of Data Used For
Double-precision data with a D exponent
Real data with an E exponent
for the real and imaginary parts of a complex
datum
Real or double-precision data without an exponent
For the real and imaginary parts of a complex
datum
Integer data
Octal data
Real or double-precision data
For integer (or logical) data
For the real and imaginary parts of a complex
datum
NOTE

The G conversion code may be
used
all but octal numeric data types.
Examples
Consider the following program segment:
INTEGER 11,12
REAL Rl,R2,R3
DOUBLE PRECISION Dl,D2
II
506
12
8
Rl
506.0
R2
13.1
R3
506001.0
Dl
13.0
D2
-504.0

13-4

for

FORMA'r ST1\TEMENT
Table 13-2 describes
the actions performed by several
types of
formatted
WRITE statements on the data given in the foregoing program
segment.
Table 13-2
Action of Field Descriptors On Sam?le Data
---'

I tern Descriptor
Form

Dw.d
Ew.d
Fw.d
Iw
Iw
Ow
Gw.d
Gw.d
Gw.d
Gw

1
2
3
.4
5

6
7

S
9
10

Sample
Descriptor

WRI TE
Sta tE~ment
Usi n9 the
Sam pIe
Des criptor

DS.2
ES.2
F5.2
15
12
05
GS.2
GS.2
G8.2
G5

0.18D+02
WRIT'E(-,-)Dl
Z.nnD nn
WRIT E(-,-)Rl
0.5lE+03
Z.nnE nn
WRIT E(-,-)R2 aa.nn
18.10
WRIT E(-,-)Il aaaan
)6)6506
WRIT E(-,-)Il
an
WRIT E(-,-)I2 nnnnn
00010
WRIT E(-,-)02
Z.nnD nn -.500+02
WRIT E(-,-)R3
Z.nnE nn
0.5lE+06
WRIT E(-,-)R2 aa.nn
)6)61618.10
WRIT'E(-,-)Il aaan
)6)6506
--- _._------ -_._------'-- -

External
Form
of Sample
Field
Described

External
Appearance
of Sample
Data

----.--~-~.-

where:

n represents a numeric character.

Z represents either a - or O.
(Note that if
a negative number cannot be output.)

a represents a digit, leading blank ()6)
sign depending on the numeric output.

n-d>6,
a

minus

Notes:
1.

In Item 1, the value Dl has only two significant
d=2, so no rounding will occur on input.

digits

In Item 2, since Rl has 3 significant digits, it
to fit into the specified field.

(w)
part of a
the width
format descriptor
In Item 5 ,
specifies an exact field
that permits no rounding of its
If the w specification is too small for the datum
contents.
to be transferred, asterisks are output to indicate that the
transfer was not made.

In Items Sand 9, the relationship between G and
fixed
floating real data is discussed in Paragraph 13.2.3.

In Items 1, 2, 3, 7, and S, the 0 and E exponent prefixes are
optional
in
the external
form of the
floating
point
constants.
For example, 1.lE+3 may be written as 1.1+3.

Table 13-3 summarizes the internal and external
specified by the numeric format conversion code.

13-5

forms

and

rounded

the

and

data

FORMAT STATEMENT
Table 13-3
Numeric Field Codes
..---------_._----_._------,----

Internal Form

------------------------_._------,

Conversion
Code
- - - - - - + - - - - - - - - _.._._-

External Form
_._------

Binary floating-point
double-precision

Decimal floating-point with D
exponent

Binary floating-point

Decimal floating-point with E
exponent

Binary floating-point

Decimal fixed-point

Binary integer

Decimal integer

Binary word

Octal value

One of the following:
single-precision
binary floating-point,
binary integer, binary
logical, or binary
complex

Single-precision decimal
floating-point, decimal
integer, logical (T or F), or
complex (two decimal
floating-point numbers),
depending upon the internal
form

_____

_ _ _ _ _ _ ___'___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ . J

Complex quantities transfer as two independent real
quantities..
The
format
specification
for
complex quantities consists of either two
successive
real
field descriptors or
one
repeated
real
field
descriptor.
For example, the statement
FORMAT(2E1S.4,2(F8.3,F8.S))
may transfer up to three complex quantities.
The equivalent of the foregoing statement is
FORMAT(EIS.4,EIS.4,F8.3,F8.5,F8.3,F8.5)

13.2.2

Interaction of Field Descriptors With I/O Variables

The execution of an I/O statement
that
specifies a
formatted
data
transfer operation initiates format control.
The actions perforined by
format control depend on information provided by the elements of
the
I/O statement's list of variables
and
the field descriptors that
comprise the referenced FORMAT statement's format specifications.
In processing each FORMAT controlled I/O statement that has
an
I/O
list,
FORTRAN-IO scans
the contents of
the list and the format
specifications in step.
Each time another variable or
array element
name
is obtained
from
the
list,
the
next field specification is
obtained from the format specification.
If the end of
the
forinat
specification is reached and more items remain in the list, a new line
or record is established and the scan process is restarted, either
at
the
first item in the format specification or, if parenthesized, sets
of format specifications exist within the format
specification,
with
the last set within the format specification.

13-6

FORMAT STI\TEMENT
When the I/O list is exhausted, control proceeds to the next statement
in
the program, but not before the FORMAT statement is scanned either
to -its end or to the next variable transfer format descriptor.
(That
is,
the
FORMAT statement is scanned past slashes, literal constants,
Hollerith field descriptors, and spacing descriptors,
but not
past
data field descriptors.)
A record is terminated by one of the following:
1.

a slash in the FORMAT specification

the delimiting right parentheses, ), of the

a lack of items in the I/O list

a lack of Hollerith
FORMAT statement

literal

field

FORM~T

statement

descriptors

the

On input, an additional record is read only when a single slash, /, is
encountered
in the
FORMAT statement.
A record is skipped when two
slashes, 1/, are encountered or a slash is followed by the end of
the
FORMAT statement.
If the
FORMAT statement finishes a record by a
slash or the end of the FORMAT statement, any data left in the
input
record
is
ignored.
If the input record is exhausted before the data
transfers are completed, the remainder of the transfer is completed as
if the record were extended with blanks.

On output, an additional record is written only when a
slash,
/,
is
encountered
in the
FORMAT statement.
If
a
pair
of consecutive
slashes, 1/, or a single slash followed
by the end of
the
FORMAT
statement is encountered, an empty record is written .

13.2.3

G, General Numeric Conversion Code
--,-----------

You may use the G conversion code in field descriptors for the
format
control of real, double-precision, integer, logical, or complex data.
With the exception of real and double-precision data,
the
type of
converSlon
performed by a type G field descriptor de?ends on the type
of its corresponding 1/0 list variable.
In the case of
real
and
double-precision data, the kind of conversion performed is a function
of the external magnitude of the datum being transferred.
Table 13-4
illustrates
the conversion performed for various ranges of magnitude
(external form) of real and double-precision data.

13.2.4

Numeric Fields with Scale Factors

You may add scale factors to D, E, F, and G conversion codes in
descriptors.
The scale factor has the form

field

nP
where n is a signed integer (+
is optional)
and
P
identifies the
operation.
When
used,
a scale factor is added as a prefix to field
descriptors.

13-7

FORMAT STATEMENT
Examples
-2PFIO.5
IPE8.2
When you add a scale factor to an type F field descriptor (or type G
if the external field is a fixed point decimal) a power of 10 is
specified so that
External Form of Number

For example, assuming the data
the field descriptor

(Internal Form)*lO**(scale factor)
invol~ed

to be the real number

26.451,

F8.3
produces the external field
}6}626.451
Table 13-4
Descriptor Conversion of Real and Double-Precision
Data According to Magnitude
Equivalent Method of
Conversion Performed

Magnitude of Data in
External Form (M)

o. 1
1

F (w- 4) • d ,4 X
F (w- 4) • (d -1) ,4 X

l\1~1

M~lO

10d-2 M~lOd-l
10d-l M~lOd
ALL OTHERS

F (w- 4) • 1 ,4 X
F (w- 4) • 0 ,4 X

Ew.d

~------------------------

L------------------------l

NOTE
In all numeric field conversions, the
field width (w)
you specify should be
large enough to include the decimal
point, slgn, and exponent character in
addition to the number of digits.
If
the specified width is too small to
accommodate the converted number, the
field will be filled with asterisks (*).
If the number converted occupies fewer
character positions than specified by w,
it will be right-justified in the field
and leading blanks will be used to fill
the field.

13-8

FORMAT S'I'ATEMENT
The addition of the scale factor of -lP
-lPF3.3
produces the external field
JzSJzSJzS2.645
When you add a scale factor to D, E, and G (external field not a
decimal fixed-point) type field descriptors, it multiplies the number
by the specified power of ten and the exponent is changed accordingly.
In input operations, type F (and type G, if the external field is
decimal fixed-point)
conversions are the only ones affected by scale
factors.
When you specify no scale factor, it is understood to be zero.
Once
you specify a scale factor, however, it holds for all subsequent types
D, E, F, and G field descriptors within the same format specification
unless another scale factor is specified. A scale factor is reset to
zero when you specify a scale factor of zero. Scale factors have no
effect on I and 0 type field descriptors.
When you add a scale factor to a D or E field descriptor, it" specifies
a power of 10 so that the external form of the number has its mantissa
multiplied by the specified power of 10;
its exponent is adjusted
accordingly.
For example, assuming the data involved to be the real number
the field descriptor

12.493,

Ell.]
produces the external field
JzSJzSO.125E+02
The addition of the scale factor 2P
2PEll.3
produces the external field
bb12 . 49E+OO
With a scale factor of zero, the number of significant digits
by a format of the form

printed

Ew.d
or
Dw.d
is the number of digits to the right of the decimal point.
For a negative scale factor nP, for d<n<O, there will be ABS(n)
leading zeros and d-ABS(n) significant digits after the decimal point,
for a total of d digits after the decimal point. If n -d, there will
be d insignificant digits (zeros) to the right of the decimal point.
If the scale factor nP is positive, for 0<n<d+2 there will be n
significant digits to the left of the decimal point and d-n+l
significant digits to the right of the decimal point (for a total of
13-9

FORMAT STATEMENT
d + 1 s i g n i f i can t dig its) .
I f n.?:.,d + 2 ,
digits and n-d-l insignificant trailing
decimal point.

there will be d+l significant
zeros on the left of the

If the data to be printed is 12.493, these formats produce results
follows:
FORMAT

OUTPUT

SIGNIFICANT
DIGITS

REASON

E15.3
IPE15.3
-lPE15.3
2PE15.3
-3PE15.3
4PE15.3
6PE15.3

bbbbbbO.125E+02
bbbbbbl.249E+Ol
bbbbbb.012E+03
bbbbbb12.49E+00
bbbbbbO.000E+05
bbbbbb1249.E-02
bbbb124900.E-04

3
4
3
4
0
4
4

n=O
n<d+2
-d<n
n<d+2
n -d
n<d+2
n d+2

13.2.5

Logical Field Descriptors

You may transfer logical data under format control in a
to numeric data transfer by use of the field descriptor

~anner

similar

Lw
where L is the control character and w is an integer specifying the
field width. The data is transmitted as the value of a corresponding
logical variable in the associated input/output list.
On input, the first non-blank character in the logical data field must
be T or F, the value of the logical variable is stored in the list
variable as true or false, respectively.
If the entire input data
field is blank or empty, a value of false is stored.
On output, w minus 1 blanks followed by T or F will be output
value of the logical variable is true or false, respectively.

13.2.6

the

Variable Numeric Field Widths

Several of the conversion codes are acceptable in FORMAT statements
without
field
width
specifications,
the w.d portion of the
specification so that can be omitted(l).
On input, the conversion codes D, E, F, G, I, L, and 0 are acceptable
without field width specifications. The field begins with the first
non-blank character encountered and ends with the first illegal
character in the given field.
(Blanks and tabs also terminate a
field.)
Note that for conversion code L (logical
data),
all
consecutive alphabetics following a T (true)
or an F (false) are
considered part of the field and are ignored.
In succeeding fields
the
input
stream
is scanned until a non-blank character is
encountered.
If the character is a comma
(,), the next field
is
skipped, and the following input field begins with the character
following the comma. Any character other than a comma is assumed to
be the first character in the next input field.
Null fields are

1. If d is given, w must also be specified.
13-10

FORMAT STATEMENT
denoted by successive commas optionally separated by blanks or
tabs.
A null
field
is equivalent to a fixed-field input of blanks.
For
example, the source code
READ 1, X, Y, Z, L, I, J
1 FORMAT (3F, L, I, A3)
with data as follows
,1.OE+5"TRUEXXXl~~~~ABC

results in
X
y

Z
L
I
J

0.0
1.OE+5
0.0
TRUE
1
IABC I

Note that if a comma is included in the input data after the XXXI
before the blanks, i.e., the data is
,1.OE+5 "
then J

and

TRUEXXXl,~~~~ABC

= I~~~I

On output, the format codes A, D,
E,
F, G,
I,
L, 0,
and Rare
acceptable'without field width specifications. The following defaults
are assumed:
Assumed Default
for KAla
for KIIO,KLIO

Format Code
r

A single-precision
A double-precision
D
E
F
G sin~le-precision
G double-precision
I
L
0
R single-precision
R double-precision

13.2.7

Alphanumeric

Fie~d

A5
AlO
D25.l6
E15.7
F15.7
G15.7
G25.l6
115
L15
015
R5
RIO

A5
AlO
D25.l8
E15:7
F15.7
G15.7
G25.l8
115
L15
015
R5
RIO

Descr~p~~~

You may accomplish the formatted transfer of alphanumeric data in a
manner similar to the formatted transfer of numeric data by use of the
field descriptors Aw and Rw, where A and R are the control characters
and w is the number of characters in the field.
The A and R descriptors both transfer alphanumeric data into or from a
variable in an input/output list depending on the I/O operation.
A
list variable may be of any type.
For example,
READ (6,5) V
5 FORMAT (~4)

13-11

FORMAT STATEMENT
causes four alphanumeric characters to be read from unit 6 and
in the variable v.

stored

The A descriptor deals with variables containing left-justified,
blank-filled characters~
the R descriptor deals with variables
containing right-justified,
zero-filled char~cters.
The following
paragraphs summarlze the result of alphanumeric data transfer (both
internal and external representations) using the A and R descriptors.
These paragraphs assume that w represents the field width and m
represents the total number of characters possible in the variable.
Double precision variables contain 10 characters (m=lO) ~
all other
variables contain 5 (m=5).
A Descriptor
1.

INPU'r, where w~ m -- The rightmost m characters of the field
are read in and stored left-justified and blank-filled in the
associated variable.

INPUT, where w < m A l l w characters are read in and stored
left-justified and blank-filled in the associated variable.

OU'I'PUT, where
right-justified
blank-filled.

OUTPUT, where w < m -- The left
associated variable are output.

m
ill
characters
are
output
and
in the field.
The remainder of the field is

most

characters

the

R Descriptor
1.

INPUT, where w~ m -- The right most m characters of the field
are read in and stored right-justified, zero-filled in the
associated variable.

INPUT, where w < m -- All w characters are read in and stored
right-justified, zero-filled in the associated variable.

OUTPUT, where w ~ en -- ;n
justified in the field.
filled.

OUTPUT, where w < m -- The right most
associated variable are output.

13.2.8

characters are output and right
The remainder of the field is blank
w

characters

the

Transferring Alphanumeric Data

You may transmit alphanumeric data directly into or from the FORMAT
statement by two different methods:
H-conversion, Or the use of
single quot2s, i.e., a literal field descriptor.
In H-conversion, the alphanumeric string is specified in the form nH,
where H is the control character and n is the total number of
characters (including blanks) in the string.
For example, you may use
the following statement sequence to print the words PROGRAM COMPLETE
on the device LPT:
PRINT 101
101 FORMAr (17HI6PROGRAM)6COMPLETE)

13-12

FORMAT ST.ATEMENT
Read and write operations of this type are initiated by I/O statements
that
reference a
format
statement and a logical device, but do not
contain an I/O list (see preceding example).
write transfers from a FORMAT statement cause
the contents of
the
statement field descriptor to be output to a specified logical device.
The contents of the field descriptor, however, remain unchanged.
Read transfers with a FORMAT statement cause the contents of the field
descriptors
involved
to be replaced by the characters input from the
specified logical device.
Alphanumeric data is stored in a field descriptor left-justified.
If
the data
input
into a
field
has fewer characters than the field,
trailing blanks are added to fill the field.
If the data
input
is
larger
than
the
field
of
the descriptor,
the excess
rightmost
characters are lost.
Examples
VvRIT E (1,101)
101 FORMAT (17HJ6PROGRAM)6COMPLETE)
cause the string PROGRAM COMPLETE to be output to the file
1.

device

Assuming the string START on device 1, the sequence
REA.D (1,101)
101 fORMAT (17HJ6PROGRAM)6COMPLE'I'E)
would change the contents of statement 101 to
101 fORMAT

(17HSTARTJ6J6J6J6J6J6J6J6J6J6~J6)

The foregoing functions may also be accomplished by a
literal
field
de!;criptor
consisting of the desired character string enclosed within·
apostrophes, i.e., 'string'.
For example, you may use the descriptors
101 FORMAT (17H}6PROGRAM}6COMPLE'I'E)
and

101 FORMAT ('}6PROGRl\Ml6COHPLETE')
in the same manner.
The result of literal conversion is
the
same as H-conversion.
On
input,
the characters between the apostrophes are replaced by input
characters, and on output,
the characters between the
apostrophes
(including blanks) are"written as part of the output data.
represented
An apostrophe character within a literal field should be
the
statement
by
two
successive apostrophe marks;
otherwise,
the
statement
containing the field will not compile.
For
example,
sequence

50 FORMAT ('DON' 'T')
PRINT 50
will compile and will cause the word DON'T to be output
printer.
The statement
50 FORMAT ('DON'T')
however, will cause a compile error.
13-13

the

line

FORMAT STATEMENT
13.2.9

Mixed Numeric and Alphanumeric Fields

You may place an alphanumeric field descriptor among other
the format.
For example, you may use the statement:
FORMAT

fields

(I4,7H~FORCE=FIO.5)

to output the line:
~~22~FORCE=~~17.68901

You may omit the separating comma after an alphanumeric format
as shown in the foregoing statement.

field,

When you omit a comma delimiter from a format specification,
format
control associates as much information as possible with the leftmost
of the two field descriptors.

13.2.10

Multiple Record Specifications

To handle a group of input/output records where different records have
different field descriptors, use a slash to indicate a new record.
For example, the statement
FORMAT (303/I5,2F8.4)
is equivalent to
FORMAT (308)
for the first record,

~nd

FORMAT (I5,2F8.4)
for the second record.
You may omit separating commas when you use a slash. When n slashes
appear at the end or beginning of a format, n blank records will be
written on output or ski~ped on input. When n slashes appear in the
n-l blank records are written on output or n-l
middle of a format,
records skipped on input.
80th the slash and the closing parenthesis at the end of the format
indicate the termination of a record.
If the list of an input/output
statement dictates that the transmission of data is to continue after
the closing parenthesis of the format is reached, the format is
repeated, starting with:
1.

that group repeat specification terminated by the last
parenthesis of the next lower level group, or

level zero if no higher level group exists.

Thus, the statement

I rei

FORMA T ( F 7 . 2 , (2 ( E1 5 . 5 , E1 5 . 4) ,I 7) )

leve~

level 1

level 2
13-14

right

FORMAT STATEMENT
causes the format
2(E15.5,E15.4) ,17
to be used after the first record.
As a further example, consider the statement
FORMAT (F7.2/(2(E15.5,E15.4) ,17»
The first record has the format
F7.2
and the next 5 records have the format
2(E15.5,E15.4) ,17

13.2.11

Record Formatting Field Descriptors
---------

You may use two field descriptors, Tw and nX, to position data
a record.

within

You may use the field descriptor Tw to specify the character
position
(external form) in which a record begins.
In the Tw field descriptor,
the letter T is the control character, and w is an unsigned
integer
constant that specifies the character position,
in a FORTRAN-10
record, where the transfer of data is to begin.
When the output
is
printed, w corresponds to the (w-l)th print position, since the first
character of the output buffer is a forms control character and is not
printed.
It is recommended that the first field specification of the
output format be IX, except where a forms control character is used.
NOTE
Two successive T field
specifications
will
result
in
the
second
field
overwriting the first field.
Examples
The statement sequence
PEINT 2
2 FORMAT (T50,'BLACK',T30,'WHITE')
causes the following line to be printed

. rIT~.

(prInt pos1t1on 29)

.rACK ..

(pr1nt pos1t1on 4 )

The statement sequence
1 FORMAT (T35,'MONTH')
READ (2,1)

.'
13-15

FORMAT STATEMENT
causes the first 34 characters of the input data associated with
logical unit 2 to be skipped, and the next five characters to replace
the characters M, 0, N, T, and n in storage.
If an input record
containing
ABCJ6J6J6XYZ
is read with the format specification

10 FORMAT (T7,A3,Tl,A3)
then the characters XYZ and ABC are read in that order.
You may use the field descriptor nX to introduce blanks into output
records or to skip characters of input records.
The letter X
specifies the operation, and n is a positive integer that specifies
the number of character positions to be either made blanks (output) or
skipped (input).
Example
The statement
FORMAT
~ay

(5H~STEP,I5,lOX,2HY=,F7.3)

be used to print the line
STEPJ6J6J628J6J6J6J6J6J6j6j6j6j6Y=j6-3.872

13.2.12

$ Format Descriptor

A $ format descriptor at the end of an output FORMAT is used to
suppress the carria)e return at the end of the current record.
It is
mainly used on terminal output but will work on non-terminal devices.
A $ format descriptor is ignored in input FORMATs and has no effect if
embedded in an output FORMAT. The $ format descriptor must be the
next format descriptor to be processed when the corresponding output
list is exhausted for the $ descriptor to have the defined effect.

13.3

CARRIAGE CONTROL CHARACTERS FOR PRINTING ASCII RECORDS

You may use the first character of an ASCII record to control the
spacing operations of the line printer or Teletype terminal printer
unit on which the record is being printed.
Specify the control
character desired by beginning the FORMAT field specification for the
ASCTr record to be output with IHa ... where a is the desired control
character.
Table 13-5 describes the control characters permitted in
FORTRAN-IO and the effect each has on the printing device.

13-16

FORMAT STA.TEMENT
Table 13-5
FORTRAN-IO Print Control Characters
_ . _ - - - - - - - - - - - - - - - - - - _ . _ - - -.--------

FORTRAN Character

Printer Character

I------------------~--

---

space

012

Skip to next
line with form
feed after
60 lines

o zero

LF,LF

012

Skip a line

lone

014

Forl1l feed - go
to top of next
page

+ plus

Suppre~3s

skipping overprint the
line

* asterisk

DC3

023

Skip to next
line with no
form feed

- minus

LF,LF,LF

012

Skip two lines

2 two

DLE

020

Space 1/2 of a
page

3 three

013

Space 1/3 of a
page

I slash

DC4

024

Space 1/6 of a
page

. period

DC2

022

Triple space
with a form
feed after
every 20 lines
printed

, comma

DCl

021

Double space
with a forin
feed after
every
30 lines
printed

NOTE
Printer control characters OLE,
DCl,
DC2,
DC3,
and DC4 affect only the line
printer.

13-17

CHAPTER 14
DEVICE CONTROL STATEMENTS

14.1

INTRODUCTION

You may use the following
source programs:

REWIND

UNLOAD

BACKSPACE(l)

ENDFILE

SKIPRECORD(l)

SKIPFILE

7•

BA.CKFILE

device

control

statements

FORTRAN-IO

The general form of the foregoing device control statements is
keyword u
keyword (u)
where
keyword
u

is the statement name
is the FORTRAN-IO logical device
Table 10-1)
.

number

(Chapter

la,

The operations performed by the device control statement are normally
used only for magnetic tape devices (MTA).
In FORTRAN-la, however,
the device control operations are simulated for disk devices.
The following paragraphs describe the
control statements.

14.2

forIn

and

use

the

device

REWIND STATEMENT
Form:

REWIND u

Use:

Move the file contained by device u to its initial
(load)
point.
If the medium is already at its load
point, this statement has no effect.
Subsequent READ

1. The results of these commands are unpredictable when used on
d ire c ted and N}'\ ~1E LIS T - con t roll e d d a t a .
14-1

list-

DEVICE CONTROL STATEMENTS
or WRITE statements that reference device u will
transfer data to or from the first record located on
the medium mounted on device u.
Example:

14.3

14.4

RE~I~D

UNLOAD STATEMENT
Form:

UNLOAD u

Use:

Move the medium contained on device u past its load
point until it has been completely rewound onto the
source reel.

Exa~ple:

U~LOAD

BACKSPACE STATEMENT
Fo en:

i3ACKSPAC(; u

use:

Move the medium contained on device u to the start of
the record that precedes the current record.
If the
precedin] record Qrior to execution of this statement
was an endfile record, the endfile record becomes the
next record after execution.
If the current record is
the first
record of the file, this statement has no
effect.
~OTE

You cannot use this statement for
files
set up for rando~ access, list-directed,'
or NAMELIST-controlled I/O operations.
Exa:nple:

14.5

BACKSPACE 16

END FILE STATEMENT
Form:

END FILE u

Use:

Write an endfile record in the file located on device
u. The endfilc record defines the end of the file that
contains it.
If an endfile record is reached during an
I/O operation initiated by a statement that does not
contain an END= option, the operation of the current
program is terminated.

Example:

END FILE 15

14-2

DEVICE CONTROL STATEMENTS
14.6

SKIP RECORD STATEMENT
Form:

SKIP RECORD u

Use:

In accessing the file located on
record
immediately
following
accessed) record.

device u, skip the
the
current (last

NOTE
You cannot use this statement for files set
for
random
access,
list-directed,
NAMELIST-controlled I/O operations.
Example:

14.7

14.8

up
or

SKIP RECORD 16

SKIP FILE STATEMENT
Form:

3KIP FILE u

Use:

In accessing the medium located on unit u, skip the
file immediately following the current (last accessed)
file.
If the number of SKIP FILE operations specified
exceeds the number of following files available, an
error will occur.

Example:

SKIP FILE 01

BACK~ILE

STATEMENT

Forll:

BACKFILE u

Use:

~ove

the medium mounted on device u to the start of the
file that precedes the current (last accessed) file.

If the number of BACKFILE operations performed exceeds
the number of preceding files, completion of the last
operation will move the medium to the start of the
first file on the medium.
Example:

14.9

BACKFILE 20

SUM!VIAH.Y Of DEVICE CONTROL STATEMENTS

Table 14-1 summarizes the
control statements

for~

and

14-3

use

the

FORTRAN-IO

device

DEVICE CONTROL

Sum~ary

State,ne'1t Form
RE'V'HND u
UNLOAD u
END FILE u
SKIP RECQRD u
SKIP FILE u
BACKFILE u
BACKSPACE u

ST~TEMENT3

T3b12 14-1
of FORTRAN-I0 Device Control 3tatements

Use
Rewind ~edium to its load point
Rewind medium onto its source reel
Write an end file re~ord into the current file
Skip the next record
Skip the next file
Hove medium backwards one file
Move medium back one record

14-4

CHAPTER 15
SUBPROGRAM STATEMENTS

15.1

INTRODUCTION

Procedures you use repeatedly in a program may be written once and
then referenced each time you need the procedure.
Procedures that may
be referenced are either internal (written and contained within the
program in which they are referenced) or external (self-contained
executable procedures that may be compiled separately). The kinds of
FORTRAN-lO procedures that may be referenced are:
1.

statement functions,

intrinsic functions (FORTRAN-lO defined functions),

external functions, and

subroutines.

The first three of the foregoing categories are
referred
to
collectively as functions or function procedures; procedures of the
last category are referred to as subroutines or subroutine procedures.

15.1.1

Dummy and Actual Arguments

Since you may reference subprograms at more than one point throughout
a program, many of the values used by the subpr00ram may be changed
each time it is used. Dummy arguments in subprograms represent the
actual values to be used, which are passed to the subprogram when it
is called.
Functions and subroutines use dummy arguments to indicate the type of
the actual argu~ents they represent and whether the actual arguments
are variables, array elements, arrays, subroutine names, or the names
of external functions.
Each dummy argument must be used within a
function or subroutine as if it were a variable, array, array element,
subroutine, or external function identifier.
Dummy argu~ents are
given in an argument list associated with the identifier assigned to
the subprogram;
actual arguments are normally given in an argument
list associated with a call made to the desired subprogram.
(Examples
of argument lists are given in the following paragraphs.)
The position, number, and type of each dummy argument in a subprogram
list must agree with the position, number, and type of each argument
list of the subprogram reference.

15-1

SUBPROGRAM STATEMENTS
Dunmy arguments may be:
1.

var iables,

-3.rray na::tes,

subroutine identifiers,

function identifiers, or

statement label identifiers that are denoted
" *", "$.1, 0 r .1 &" •

the

symbol

When you reference a subprogram, its dum~y ar~u~ents are replaced by
the corresoonding actual ar)uments supplied in the reference.
All
appearances of a du~my arju~ent within a function or subroutine are
related
to the given actual arguments.
Except for
subroutine
identifiers and literal constants, a valid association between dummy
and actual argu~ents occurs only if both are of the same type~
otherwise,
the results of the subprogram computations will
be
un~redictable.
~rgu~ent as~ociation may be carried through more than
one level of subprogram reference if a valid association is maintained
through
each
1 evel .
The
dummy/actual
argul11en t
assoc ia t ions
established when a subprogram is referenced are terminated when the
desired sub9rogram operations arc completed.
The following rules govern the use and form of dummy arguments:
1.

The nu~ber and type of the dU~11Y argu~ents of a procedure
must be the same as the number and type of the actual
arJu~ents given each time the procedure is referenced.

Dum~y argument names may not appear in EQUIVALENCE, DATA,
COMMON statements.

A variable dummy argument should have a variable,
an array
element identifier, an expression, or a constant as its
corresponding argument.

An array jum~y argu~ent should have either an array name or
an array element identifier as its corresponding actual
argument.
If the actual argument is an array, the length of
the dummy array should be less than or equal to that of the
actual array.
Each element of a dummy array is associated
directly with the corresponding elements of the actual array.

~ dummy argu~ent representing a subroutine identifier
hav2 a subroutine name as its actual arqument.

A du~my argument representing an external function must
an external function as its actual argument.

A dummy argument may be defined or redefined in a referenced
subprogram only if its corresponding actual argument is a
variable.
If dummy arguments are array names, then elements
of the array may be redefined.

should
have

\dditional information regarding the use of dummy and actual arguments
is given in the description of how subprograms are defined and
referencc~d .

15-2

SUBPROGRAM STATEMENTS
15.2

STATEMENT FUNCTIONS

Statement functions define an internal subprogram in
statement. The general form of a statement function is:

single

n arne (Ci r g 1 , a r g 2 , . . . ,a r 9 n ) = E
where
name

is a name you assign that consists of one to six
characters.
The name you use must conform to the
rules for symbolic names given in Section 3.3.
The type of a statement function is determined
either by the first character of its name or by it
being explicitly declared in a type statement.

(argl ... argn)

represents a list of dummy arguments.

is an arbitrary expression.

The expression E of a statement function may be any legitimate
arithmetic expression that may use the given dummy arguments and
indicates how they are combined to obtain the desired value.
You may
use the dummy arguments as variables or indirect function references~
but you cannot use them as arrays.
The dummy argument names bear no
relation to their use outside the context of the statement function
except for their data type.
The expression may reference FORTRAN-IO
defined functions
(Paragraph 15.3)
or any other defined statement
function, or call an external function.
It may not reference any
function that directly or indirectly references the given statement
function or any subprogram in the chain of references.
That is,
recursive references are not allowed.
Statement functions produce
only one value, the result of the expression that it contains.
A
statement function cannot reference itself.
You must define all statement functions within a program unit before
the first executable statement of the program unit. When used, the
statement function name must be followed by an actual argument list
enclosed within parentheses and may appear
in any arithmetic or
logical expression.
Examples:
SSQR(K)=(K*(K+l)*2*K+l)/6
ACOSH(X)=(EXP(X/A)+EXP(-X/A))/2.0

15.3

INTRINSIC FUNCTIONS (FORTRAN-IO DEFINED FUNCTIONS)

Intrinsic functions are subprograms that are defined and supplied by
FORTRAN-IO.
You can reference an intrinsic function by using its
assigned name as an operand in an arithmetic or logical expression.
Table 15-1 describes the names of the FORTRAN-IO intrinsic functions,
the type of the arguments that each accepts, and the function it
performs.
These names always refer to the intrinsic function unless
they are preceded by an asterisk (*) or ampersand (&) in an EXTERNAL
statement, declared in a conflicting explicit type statement, or are
specified as a routine dummy parameter.

15-3

NOTE
Octal constants may only be used as
actual input to an intrinsic function
when
the
function
expects
octal
argu~ents.

Table 15-1
Intrinsic Functions (FORTRAtJ-IO Defined Functions)
Function

I·; n e 1':10 n i c

Definition

Number of
ArguDents

Type of
Functlon
Argument

w
w

Absolute value:
Real
Integer
Double- precision
Com~lex to real

~
I

o
ABS*
IABS*
DAES*
CABS

arg
arq
ara
c=(x**2+Y**L)**(1/2)

1
1
1
1

Peal
Integer
Double
Real

Real
Integer
Double
Complex

~
~

~
~
~
~

Conversion:
Integer to real
Real to integer

FLOA'I'**
IFIX**

GouDIe to real
1\.eal to double

SNGL
DBLE*

Sign of arg *
largest integer
~ larg I

* In line functions.
**In line functions on KIlO and KLIO only.

1
1

Integer
1\.eal

1
1

Double
Real

Real
Integer
Peal
Double

Table 15-1 (Cont.)
Intrinsic Functions (FORTRAN-lO Defined Functions)
Function

Number of
Arguments

Definition

MnemoniC]

i
Integer
Complex
(obtain
Complex
(obtain
part)
Real to

DFLOAT
REAL*

to double
to real
real part)
to real
imaginary

An'lAG

complex

Integer
Complex

Double
Real

Complex

Real

Complex

1
1

c=Arg + i*Arg

CMPLX*

Type of
FunctIon

I Argument

(f)

o::l

Truncation:
Real to real

Sign of arCl*
largest integer
~ I arg I

AIN'T

I---'
U1

I
U1

Real to integer
Double to integer

Real

:::c

):or

INT*
IDINT

1
1

Reel
Double

Integer
Integer

'""'"

en
r-3

):or

1-3
tr:I

Remaindering:
Real
Integer
Double- precision

tTl

Al10D
f-iOD*
i

D~1CD

AhAXO
Ai1AXl *
MA X 0 *

The re~a.inder
}
when Arq 1 is
{divided by ll.rg 2

2
2
2

Real
Integer
i Double

Real
Integer
Double

>1
>1
>1

Integer
[.;eal
Intc:Jer
Real
Double

Feal
Real
Integer
Ir:teljer
Double

i'laximur.1 value:

HAXI
DMAXI

* In line functions.

(

)

tLvi a x (A r 9 1 , A r g 2 , • • • )

)

(

Z
t-3

(f)

Table 15-1 (Cant.)
1ntrinsic Functions (FGfTFAn-10 DefirH?ri Functions)
Function

I :'lner.:oni:-!

['e fin it ion

Nu~ber of
ArguDents

l\rquDent

of
Function

>1
>1
>1
>1
>1

Inteoer
Real
Integer
Real
Double

Real
Real
Integer
Integer
Double

:.j i n i mu h' Val u e :
.AtlINO
AI'lIN 1 *

MINO*
l':INl
[;('1I N 1

!Min (Argi ,Arq2, •••

::s:

I--'
U1

I
0'1

c
co
I'\J
:::u
o
CJ
:::u

Transfer of Sign:
Real
Inteqer
Double precision

SICN*
ISIGN
DSIGN

{sgn

(IIrq 2) * IArg il}

2
2

Re3l
Inte'}er
Double

Real
Inteser
Cauble

1-:1

M
3:
tTl

Z
t-1

positive Difference:
Real
Integer
* In line functions.

(j)

DIH*
IDIt-l

{ Ar 9 1 - [,~ i n ( Ar q 1 , Ar 9 2 )}

2
2

Real
Integer

SUBPROGRAM STATEMENTS

15.4

EXTERNAL FUNCTIONS

External functions are function subprograms that consist of a FUNCTION
statement
followed by a sequence of FORTRAN-IO statements that define
one or more desired operations~
subprograms of this type may contain
one or more
RETURN statements and must be
terminated by an END
statement.
Function subprograms are independent programs that may be
referenced by other programs.
The FUNCTION statement that identifies an external
form:

function

has

the

type FUNCTION name

(argl,arg2, ... ,argn)

type

is an
optional
type
specification
as
described
1n Section
6.3.
These
include
INTEGER, REAL, DOUBLE PRECISION,
COMPLEX or
LOGICAL (plus the optional size modifier, *n,
for compatibility with other manufacturers.)

name

is the name you assign to the function.
The
name
may
consist
of
from one
to
six
characters,
the
first
of which must
be
alphabetic.
You may
include
the optional
size modifier (*n) with the name if the
type
is specified.
(Refer to Section 6,.3. )

(argl, ... ,argn)

is a list of dummy arguments.

where

If you omit type in the FUNCTION statement, the type of
the
function
may be
assigned, by default, according to the first character of its
name, or may be specified by an IMPLICIT statement or by an explicit
statement given with the subprogram itself.
Note that if you want to use the same name for a user-defined function
as
the
name of a FORTRAN-IO defined function (library basic external
function), the desired name must be declared in an EXTERNAL statement
and prefixed by an asterisk (*) or ampersand (&) in the referencing
routine.
(Refer to Section 6.7 for
a
description of
the
EXTERNAL
statement.)
The following rules govern the structuring of a FUNCTION subprogram:

You must use the symbolic name assigned a FUNCTION subprogram
as a variable name in the subprogram.
During each execution
of the subprogram, this variable must be defined and,
once
defined,
may be
referenced or redefined.
The value of the
variable at the time of execution on any RETURN statement
is
the value of the subprogram.
NOTE
A RETURN statement returns control
to
the calling
statement
that
initiated
the execution of
the
subprogram.
See Section 15.6 for
a description of
this statement.

15-7

SUBPROGRAM STATEMENTS
2.

You may not use the symbolic name of a FUNCTION subprogram in
any nonexecutable
statement in the subprogram except in the
initial FUNCTION statement or a type statement.

Dummy argument names
may not appear
in any EQUIVALENCE,
COMMON, or DATA statement used within the subprogram.

The function subprogram may define or redefine one or more of
its arguments so as to effectively return results in addition
to the value of the function.

The function subprogram may contain any FORTRAN-lO statement
except BLOCK DATA,
SUBROUTINE PROGRAM,
another
FDNCTION
statement, or
any statement
that directly or
indirectly
references
the
function
being defined or any subprogram in
the chain of subprograms leading to this function.

The function subprogram should contain at
least one
RETURN
statement and must
be terminated by an END statement..
The
RETURN statement signifies a
logical
conclusion of
the
computation made
by the subprogram and returns the computed
function
value and control
to
the calling program.
A
subprogram may have more than one RETURN statement.
The
END statement specifies
the
subprogram and implies a return.

15.4.1

Basic External Functions

physical

end

the

(FORTRAN-lO Defined Functions)

FORTRAN-lO contains a group of predefined external functions that
are
called basic functions.
Table 15-2 describes each basic function, its
name, and its use.
These names always refer
to
the basic external
functions
unless declared in an EXTERNAL or conflicting explicit type
statement.

15.4.2

Generic Function Names

The compiler generates a
call
to
the proper
FORTRAN-lO defined
function,
depending on
the type of the arguments, for the following
generic function names:
ABS
AMAXI
AMINI
ATAN
ATAN2
COS
INT
MOD
SIGN
SIN
SQRT
EXP
ALOG
ALOGlO
In the following example
K=ABS(I)

15-8

SUBPROGRAM STATEMENTS
the type of I deteL~ines which
function
is called.
If
I
is
an
integer,
the compiier generates a call to the function lABS.
If I is
real, the compiler generates a call to the
function
ABS.
If
I
is
double precision, the compiler generates a call to the function DABS.
The function name loses its generic properties if
it appears
in an
explicit
type
statement,
if
it
is
specified
as
a dummy routine
parameter, or if
it
is prefixed
by
"*" or
"&"
in an
EXTERNAL
statement.
When a generic function name that was specified unprefixed
in an EXTERNAL statement is used as a routine parameter, it is assumed
to
reference a
FORTRAN-IO defined function of the same name, or if
none exists, a user-defined function.
Note that
IMPLICIT statements
have no effect upon the data type of generic function names unless the
name has been removed from its class by use of an EXTERNAL statement.

15.5

SUBROUTINE SUBPROGRAMS

A subroutine is an external computational procedure that is identified
by a
SUBROUTINE statement and mayor may not return values to the
calling program.
The
SUBROUTINE statement
used
to
identify
a
subprogram of this type has the form:
SUBROUTINE name(argl,arg2, ... ,argn)
where
name

is the symbolic name of the subroutine to
defined.

(argl, ... ,argn)

is an optional list of dummy arguments.

15-9

Table 15-2
Basic External Functions (FORTRAN-lO Defined Functions)

--------,---------------------------1----_---1Definition

i1ne!:1on ic I

Function

NUJ.lber ot
Arguments

-- -------- ----Type ot
Function
Argument

Exponential:
Real
Double
Complex

EXP
DEXP
CEXP

t9}

1
1
1

Real
Double
Co:nplex

Peal
Double
Complex

C/:l

d
!J1
t-c1

Logarithf.1:
Real
!

I--'
Ul

I
I--'

Double
Complex

ALOG
ALOGIO
DLOG
DLOGIO
CLOG

In (Arg)
(Arg)
log
In (Arg)
log
(Arg)
In (Ara)

1
1
1
1
1

Real
Real
Double
Double
Complex

oG)

8::
Cf)

t-3

trj

8::

trj

Square Root:
Real
Double
Complex

SQRT*
DSQRT
CSQRT

Sine:
Real

SIN*

(radians)

*Generic functions

(Ar(~n ** 1/2

(Arg)**1/2
(Arg)**1/2

1
1
1

Real
Double
Complex

Real

t-3

Cf)

m_~'_

.LOU.l.C

.l..J-~

__ ~

\'--VlIL.}

Basic External Functions (FORTRAN-IO Defined Functions)

1 - -_ __ _

p'ln,...t-i(")n
....
.....
......

J\,~~Pr!"~~~"
....
... .. I
~

npf1~H"'1il~
--_ ......... __ _....
.....

D,...." 1

(rlt""'>r. ... "'t""'>C' \

Double (radians)
COr.1plex

DSIN
CSIN

Cosine:
Real (radians)
Real (deg r ees)
Double (radians)
Conplex

COS*
COSD
DCOS
CCOS

{Sin

Tvnt=of
-.l. c---

-~-~

l'~:~OT.hpr
.. -- .... "
- fArguments

Argument
I Real

(Ar g )}

\COS (Ar g )\

1
I

I
I
I

Double
Complex

Real
Double
Complex

Real
Real
Double
Complex

hyperbolic:

Sine
Cosine
Tangent

CJ)

C
IJ:I

'I:j

:;0

oG)

I--'

I
i--'
I--'

-----1

Function

SINH
COSH
TANH

sinh(Arg)
cosh(Arg)
tanh (].'\rg)

I
I
I

Real
Real
Real

CJ)

:t:'
~
tIj

tIj

:z:

Arc sine

ASIN

asin(Arg)

Real

Arc cosine

ACOS

acos(Arc:;)

Real

Arc tar.gent
.Real
Double
Two REAL argur.1ents

ATAN*
DATAtJ
ATAt~ 2*

atan(l\rg)
datan(Arg)
atan (lHgI/Arg2)

1
1

Real
Double
Real

*Generic functions

~
CJ)

Table 15-2 (Cont.)
Easic External Functions (FOBTRAN-IC Defined Functions)
Function

! rl\nernon ic

Number of

Definition

Ty?e of
Function
Argument

~rgu~ents

Two DOUBLE argur.lents

DA'l'AN 2

atan(Argl/Arg2)

Double

CONJG

Arg=X+iy,CONJG=X-iY

COr.1?lex

Complex

(f)

c::::

Complex Conjugate

tJj

tU
~

I-'

Random Number

RAN

I
I-'
tv

Result is a rando~
number in the range
of 0 to 1.0

Integer,
Real,
Double,
or

1 Duml.1Y

Argument

Real

t-3

!J::l

I
Remainder of time limit

TIM2GO

Remainder of time
limit for job in
seconds

1 Dummy

Integer,
Real,
Double,
or Complex

Argument

--------

-------

~
(f)

Real

t-3
M

:s:

t-3

(f)

SUBPROGRAM STATEMENTS
The
following
subprogram:

rules

control

the

structuring

subroutine

You may not use the symbolic name of the
subprogram
in any
statement within the defined subprogram except the SUBROUTINE
statement itself.

You may not use the given dummy arguments in an
EQUIVALENCE,
COMMON, or DATA statement within the subprogram.

The subroutine subprogram may define or redefine one or
of its arguments so as to effectively return results.

The subroutine
subprogram may
contain
any
FORTRAN-IO
statement except BLOCK DATA,
FUNCTION, another SUBROUTINE
statement,
or
any statement that
either
directly
or
indirectly references the subroutine being defined or any of
the subprograms in the chain of subprogram references leading
to this subroutine.

Dummy arguments that represent statement labels may be either
an *, $, or &.

The subprogram should contain at least one
RETURN statement
and must be
terminated
by an
END statement.
The RETURN
statements
indicate
the
logical
end of a
computational
routine;
the END statement signifies the physical end of the
subroutine.

Subroutine subprograms may have as many entry points as
desired
(see description of ENTRY statement given in Section
15.7) •

.
'

15.5.1

Referencing Subroutines

(CALL Statement)

You must reference subroutine subprograms by using a CALL statement of
the following form:
CALL name(argl,arg2, ... ,ar~n)
where
name

is the
symbolic
name
subroutine subprogram.

(argl, ... ,argn)

is an optional list of actual arguments.
If
the
list
is
included,
the given actual
arguments must agree in order,
number,
and
type with
the corresponding dummy arguments
given in the defining SUBROUTINE statement.

the

The use of literal constants is an exception
to
the
rule
agreement of type between dummy and
actual arguments.
argument in a CALL statement may be:
1.

a constant

a variable name

15-13

desired

requiring
An actual

SUBPROGRAM STATEMENTS
3.

an array element identifier

an array name

an expression

the name of an external subroutine, or

a statement label.

Example:
The subroutine
SUBROUTINE MATRIX ( 1 ,.} , K, M, *}

END
way be referenced by
CALL MATRIX(lO,20,30,40,$lOl)

15.5.2

FORTRAN-IO Supplied Subroutines

FORTRAN-IO provides you with an extensive group of
predefined
subroutines.
Table 15-3 gives the descriptions and names of these
predefined subroutines.

15.6

RETURN STATEMENT

AND

MULTIPLE RETURNS

The RETURN statement causes control to be returned from a
to the calling program unit.
This statement has the form:
RETURN

(standard return)

RETURN e

(multiple returns)

subprogram

where e represents an integer constant, variable, or expression.
The
execution of this statement in the first of the foregoing forms (i.e.,
standard return) causes control to be returned to the statement of the
calling program that follows the statement that called the subprogram.
The multiple returns form of this statement, i.e., RETURN e, enables
you to select any labeled statement of the calling program as a return
point. When the multiple returns form of this statement is executed,
the assigned or calculated value of e specifies that the return is to
be made to the eth statement label in the argument list of the calling
statement.
The value of e should be a positive integer that is equal
to or less than the number of statement labels given in the argument
list of the calling statement.
If e is less than 1 or is larger than
the number of available statement labels, a standard return operation
is performed.

15-14

SUBPROGRAM STATEMENTS

NOTE
A dummy argument for a
statement label
must be either a *, $, or & symbol.
You may use any number of RETURN (standard return) statements
in any
subprogram.
The use of
the multiple
returns
form of the RETURN
statement, however, is
restricted
to
subroutine subprograms.
The
execution of a RETURN statement in a main program will terminate the
program.
Example
Assume

th~

following statement sequence in a main program:

CALL EXAMP(1,$10,K,$15,M,$20)
GO TO 101

15-15

SUBPROGRAM STATEMENTS
Assume the following
subprogram:

statement

sequence

the

called

SUBROUTINL

SUBROUTINe EXAHP (L, *,M, *,H,*)

RETURN

RETURN (C/D)

END
Each occurrence of RETURN returns control to the statement GO
in the calling program.
If, on the execution of the RETURN (C/D) statement, the value of
is:

a standard return to the GO TO
statement is made
the return is made to statement 10
the return is made to statement 15
the return is made to statement 20

1
2
3

Greater than or equal to:
4

15.6.1

Referencing

Externa~

(C/D)

The following is performed:

Less than or equal to:

101

The following is performed:
a standard return to the GO TO 101
statement is made.

FUNCTION Subprogram

Reference an external function subprogram by using its assigned name
as an operand in an arithmetic or logical expression in the calling
program unit. The name must be followed by an actual argument list.
The actual arguments in an external function reference may be:
1.

a variable name,

an array element identifier,

an array name,

an expression,

a statement number, or

15-16

SUBPROGRAM STATEMENTS
6.

the name of
SUBROUTINE) .

another

external

procedure

FUNCTION

NO'IIE
Any subprogram name to
be
used
as an
argument
to another
subprogram must
first appear in an
EXTERNAL statement
(Chapter 6) in the calling proc:Jrar'1 unit.
Example
The subprogram defined as:
INTEGER FUNCTION ICALC(IX,IY,IZ)

RETURN
END
may be referenced in the following manner:

TOTAL=ICALC(IAA,IAB,IAC)+500

15.7

MULTIPLE SUBPROGRAM ENTRY POINTS

(ENTRY STATEMENT)

FORTRAN-lO provides an ENTRY statement that enables you
to specify
additional
entry points into an external subprogram.
This statement
used in conjunction with a RETURN statement enables you to employ only
one computational
routine of a subprogram that contains several such
routines.
The form of the ENTRY statement is:
ENTRY name(argl,arg2, •.. ,argn)
where
name

is the
symbolic
name
desired entry point

(argl, .•. ,argn)

is an optional list of dummy arguments.
list may contain
1.

variable names,

array declarators,

15-17

assigned

the
This

SUBPROGRAM STATEMENTS
procedure

the name of
an
external
(SUBROUTINE or FUNCTION), or

identifiers that
are
statement label
denoted by either a *, $, or & symbol.

The rules for the use of an ENTRY statement follow:
1.

The ENTRY statement allows entry into a subprogram at a place
other than that defined by the subroutine or function
statement. You may include any number of ENTRY statements in
an external subprogram.

Execution is begun at the first
following the ENTRY statement.

Appearance of an ENTRY statement in a subprogram does not
negate the rule that statement functions in subprograms must
precede the first executable statement.

Entry statements are nonexecutable
execution flow of a subprogram.

affect

the

You may not use an ENTRY statement in a main program or
a subprogram reference itself through its entry points.

have

You may not use an ENTRY statement in the range of a DO or an
extended DO statement construction.

The dummy arguments in the ENTRY statement need not agree in
order, number, or type with the dummy arguments in SUBROUTINE
or FUNCTION statements of any other ENTRY statement in the
subprogram. However, the arguments for each call or function
reference must agree with the dummy arguments in
the
SUBROUTINE, FUNCTION, or ENTRY statement that is referenced.

Entry into a subpro0ram initializes only the dummy
of the referenced ENTRY statement.

YOll may not reference a dummy argument unless it appears in
the dummy list of an ENTRY, SUBROUTINE, or FUNCTION statement
by which the subprogram is entered.

10.

The source subprogram must be ordered such that references to
dummy
arguments
in
executable
statements follow the
appearance of the dummy argument in the dummy list of a
SUBROUTINE, FUNCTION, or ENTRY statement.

11.

Dummy arguments that were defined for a subprogram by some
previous reference to the subprogram are undefined for
subsequent entry into the subprogram.

12.

The value of the function must be
current entry name.

15-18

statement

executable

and

returned

not

use

arguments

the

SUBPROGRAM STATEMENTS
Table 15-3
FORTRAN-IO Library Subroutines
Subroutine Name

Effect

\ - - - - - - - ' - - - - - - - - - - - ----,-------,--------- - - - - - - - --- - - - -----------

CALL AXIS(X,Y,ASC,NASC,S,THETA,XMIN,DX)

AXIS

AXIS causes an axis with tick marks and scale values
at I-inch increments to be drawn. An identifying
label may also be plotted along the axis.
Parameters
X and Y specify the start of the axis. The axis is
plotted, starting at X, Y, at an angle of THETA
degrees for a distance of S inches. The angle THETA
is usually either 0 (X axis)
or 90.0
(Y axis).
Characters ASC of array ASC are plotted as a label
for the axis drawn.
If NASC is positive, the tic
marks, label, and scale values are placed on the
counterclockwise side of the axis;
if NASC is
negative, the foregoing items are placed on the
clockwise side of the axis.
Parameter XMIN is the value of the scale at the
beginning of the axis; parameter DX is the change in
scale for a I-inch increment. The values of XMIN and
DX may be determined by subroutine SCALE.
DATE

CALL DATE (array)
This subroutine places today's date as left-justified
ASCII characters into a dimensioned 2-word array.
The date is in the form:
dd-mmm-yy
where dd is a 2-digit day (if the first digit is 0,
it is converted to a blank), mmm is a 3-letter month
abbreviation, e.g., Mar, and yy is a 2-digit year.
The data is stored in ASCII code, left-justified, in
the two words.

DEFtNE FILE

CALL DEFINE FILE (u,s,v,f,pj,pg)
The arguments
follows:
u

.
'

this

subroutine

are

defined

logical FORTRAN-IO device numbers.
the size of the records comprising the file
being defined. The argument s may be an integer
constant or variable.

an associated variable. The associated variable
is an integer variable that is set to a value
that points to the record that immediately
follows
the last record transferred.
This
variable is used by the FIND statement
(Chapter
10) .
At the end of each FIND operation, the
variable is set to a value that points to the
record found.
The variable v cannot appear in
the I/O list of any I/O statement that accesses
the file set up by the DEFINE FILE statement .

15-19

SUBPROCRAM STATeMENTS
Table 15-3 (Cant.)
FORTRAN-10 Library Subroutines
Subroutine Name

Effect

f =

filename to be given the file being defined.

your project number.

your programmer's number.
NOTE
Numbers pj and
Directory.

identify

your

File

Example
The statement
CALL DEFINE FILE

(l,lO,ASCVAR,'FORTFL.DAT',O,O)

establishes a file named FORTFL.DAT on device
01,
a
disk,
which
contains
ten
word
records.
The
associated variable is ASCVAR, and
the
file
is
in
your area.
A DEFINE FILE call
can be
used
to establish and
define
the
structure of each file to be used for
random access I/O operations.
NOTE
the OPEN statement may be uSed to perform the
same functions as DEFINE FILE.
DUMP

CALL DUMP (L(l) ,1](1) ,F(l) , ... ,L(n) ,U(n) ,F(n»
DUMP causes particular portions of core to be dumped.
L(l)
and
U(l)
are the variable names that give the
limits of core memory to be dumped.
Either
L(l)
or
U(l)
may be upper or lower limits.
F(l) is a number
indicating the format in which
the dump
is to be
performed:
= octal, 1 = real, 2 = integer, and 3 =
ASCII.

If F is not 0, 1, 2, 3, the dump
is
in octal.
If
F(n) is missing, the last section is dumped in octal.
If U(n) and F(n) are missing, an octal dump
is made
from
L to
the end of the job area.
If L(n), U(n),
and F(n) are missing, the entire job area
is dumped
in octal.
The dump is terminated by a call to EXIT.

15-20

SUBPROGRAM STATEMENTS
Table 15-3 (Cont.)
FORTRAN-IO Library Subroutines

r------------------

-------------------------~

Subroutine Name
E:RRSET

-" -. -------

Effect
CALL ERRSET(N)

ERRSET allows you to control
the
typeout
of
execution-time arithmetic error messages. ERRSET is
called with one integer argument.
Typeout of all arithmetic and library error messages
is suppressed after N occurrences of these error
messages.
If ERRSET is not called, the default value
of N is 2.
E:RRSNS

CALL ERRSNS{I,J)
ERRSNS allows you to determine the exact nature of an
error on READ, WRITE, OPEN, or CLOSE that was trapped
with the "ERR= statement label" option.
ERRSNS
returns one or two integer values that describe the
status of the last I/O operation perfor~ed by FOROTS.
(The second integer value is optional.)
CALL ERRSNS(I,J)
returns a FORTRAN-standardized number in I and a
processor-dependent number in J to describe the last
I/O operation. See Appendix H and Table B-1 for more
information and a detailed description of the values
returned .

.
-

EXIT

EXIT
EXIT returns control to the Monitor and,
terminates the execution of the program.

ILL

therefore,

CALL ILL
ILL sets the ILLEG flag.
If the flag is set and an
illegal
character
is
encountered in floatingpoint/double- precision input, the corresponding word
is set to zero.

LEGAL

CALL LEGAL
LEGAL clears the ILLEG flag.
If the flag is set and
an illegal character is encountered in the [lor1.tingpoint/double- precision input, the corresponding word
is set to zero.

LINE

CALL LINE (X,Y,N,K)
LINE causes a line to be drawn through the N points
specified
by
(X{l) ,Y{l)), (X(2) ,Y(2)) ... (X{N) ,Y(N))
where the elements of X and Y are spaced K words
apart in storage.

15-21

SUBPROGRAM STATEMENTS
Table 15-3 (Cont.)
FORTRAN-IO Library Subroutines
Subroutine Name
MKTBL

Effect
CALL f'1KTBL(I,J)

MKTBL specifies a special character set where I is
the number to be assigned the set and J contains the
starting address of a character table of 200(8)
consecutive words.
In each character table word, the
left half contains the number of strokes in the
character
(0 if nothing is to be plotted for the
word) and the right.half contains the address of the
table of strokes for the character.
NUMBER

CALL NUMBER(X,Y,SIZE,FNUM,THCTA,NDIGIT)
NUMBER causes a floating- point number to be plotted
as text.
Parametecs X, Y, SIZE, and THETA have the
same meanings as for the SYMBOL call.
Parameter
NDIGIT is the number of digits plotted to the right
of the decimal point.
If NDIGIT is a negative value,
only the integer part of the number is plotted. FNUM
specifies the number to be plotted.

PDUMP

CAL L P DUr-1 P ( L ( 1) , U ( 1) ,F ( 1) , . . . , L ( n) , U (n) ,F (n)
The arguments of PDUMP are the same as those of
DUMP.
PDUMP is the same as DUMP except that control
returns to the calling program after the dump has
been executed.

PLOT

CALL PLOT(X,Y,IPEN)
PLOT moves the pen in a straight line from its
current position to the position specified by X,Y.
If IPEN=3, the pen is raised before the movement;
if
IPEN=2 the pen is lowered before movement;
if IPEN=1
the pen is left unchanged from its previous state.
If the value of IPEN is negative (-I, -2 or -3) the
pen action is the same as for the corresponding
positive values except that on completion of the
indicated motion, the new pen position is taken as a
new origin and the output buffer is sent to the
plotter.
The plotter is not released
specified movement.

PLOTS

completion

the

CALL PLOTS (I)
PLOTS is the plotter actup routine.
If the pIotter
is not availab10,
I is set to -1;
if it is
available, I is set to O.
This call must bE? the
first plotter routine called.

15-22

SUBPROGRAM STATEMENTS
Table 15-3 (Cant.)
FORTRAN-IO Library Subroutines
Subroutine Name
RELEAS

Effect
CALL RELEAS(unit)

RELEAS closes out I/O on a device initialized by the
FORTRAN Operating System and
returns
it
to the
uninitiali~ed state.
RELEAS should be the last call
referencing that device.
SAVRAN

CALL SAVRAN(I)
SAVRAN is called with one integer
argument.
SAVRAN
sets
its
argument
to
the last
random number
(interpreted as an integer) that has been generated
by the function RAN.

SCALE

CALL SCALE(X,N,S,XMIN,DX)
SCALE selects scale values for an AXIS call
where
X
and N specify a I-dimensional array X with the length
N.
Parameter S specifies the length of
the desired
axis, SCALE determines a value of DX that allows X to
be plotted in S inches.
XMIN is selected as
the
smallest element of the array X, and is truncated to
be a multiple of DX.

SETABL

CALL SETABL(I,J)
SETABL specifies a
character
set where
I
is an
integer
that
gives
the
number
of
the desired
character set.
If a character set has been defined
by
I,
the value of J is set to 0;
if not, J is set
to -1.
The standard ASCII character set
is defined
as 1.

SETRAN

CALL SETRAN

(I)

SETRAN has one argument, which must be a non-negative
integer
<2(31).
The starting value of the function
RAN is set to the value of this argument, unless
the
argument
is zero.
In this case, RAN uses its normal
starting value.
SLITE

CALL SLITE(I)
SLITE turns sense lights on or off.
I is an
integer
expression.
For 1~I~36, sense light I will be turned
on.
If 1=0, all sense lights will be turned off.

SLITET

CALL SLITET(I,J)
SLITET checks the status of sense light I,
sets the
variable J accordingly, and turns off sense light I.
If i is on, j is set to 1;
and if i is off, j is set
to 2.

15-23

SUBPROGRAM STATEMENTb
Table 15-3 (Cont.)
FORTRAN-IO Library' Subroutines
Subroutine Name
SORT

Effect
CALL SORT ('OUTPUT/SWS=INPUT/SWS,INPUT/SWS')

SORT sorts one or more files using the SORT program.
The argument
is an ASCII
string
that represents
(version
3 or
later)
the standard SORT command
string.
Its components are:
OUTPUT
INPUT
SWS

file specification of the output file.
file specification of the input file(s).
one or more switches for the output file,
the input file(s), the sorting process, and
sometimes SCAN.
The switches not allowed
in the
FORTRAN call
are:/BLOCK, /COMP3,
/EBCDIC, /INDUSTRY,
/LABEL,
/SIXBIT,
and
/VERSION.

Wild card format is not allowed in the FORTRAN call.
For information about using the SORT program, see the
SORT USER'S GUIDE (AA-0997C-TB).
Example:
CALL SORT('SRTFIL.SRT=INSTRT/REC:80/KEY:l:2')
SSWTCH

SSWTCH(I,J)
SSWTCH checks the status of data switch
i
(O~i~35)
and sets the variable J accordingly.
If I is set
OFF, J is set to 1;
and, if I is ON, J is set to 2.

SYMBOL

CALL SYMBOL(X,Y,SIZE,ASC,THETA,NASC)
SYMBOL raises the plotter pen and moves
it to
position specified by X and Y.
Lower pen and plot
characters found
in array ASC.
Parameter
SIZE
specifies the height of
the characters plotted in
inches (floating- point values);
THETA specifies the
direction of the base line on which the text of array
ASC is to be plotted, and NASC specifies the number
of characters in array ASC.

TIME

CALL TIME(X) or CALL TIME(X,Y)
TIME returns the current time in its argument(s)
in
left-justified ASCII characters.
If TIME is called
with one argument,
CALL TIME(X)
the time is in the form
hh:mm
where hh is the hours (24-hour time) and mm
minutes.
If a second argument is requested,
CALL TIME(X,Y)

15-24

the

SUBPROGRAM STATEMENTS
Table 15-3 (Cont.)
FORTRAN-IO Library Subroutines
Subroutine Name

Effect

the first argument is returned in the same
form as
the one-argument call, and the second has the form
bss.t
where b is a blank, ss is in seconds,
tenths of a second.
v~HERE

and

CALL WHERE(X,Y}
Variables X and
Yare set to the values
identify the current position of the pen.

15-25

which

CHAPTER 16
BLOCK DATA SUBPROGRAMS

16.1

INTHODUCTION

Use block data subprograms to initialize data to be stored in any
common areas.
You may use only specification and DATA statements,
i.e., DATA, COMMON, DIMENSION, EQUIVALENCE, and TYPE,
in BLOCK DATA
subprograms.
A subprogram of this type must start with a BLOCK DATA
statement.
You may enter initial values into more than one labeled
in a single subprogram of this type.

common

block

An executable program may contain more than one block data subprogram.

16.2

BLOCK DATA STATEMENT

The form of the BLOCK DATA statement is:
BLOCK DATA name
where
name

is a symbolic
subprogram .

.
'

16-1

name

given

ldentify

the

APPENDIX A
ASCII-1968

CH~RACTER

CODE SET

The character code set defined
in the X3.4-l968 Version of the
American National Standard for
Information Interchange (ASCII) is
given in the following matrix.
1st 2
octal
digits

Last octal digit
0
I

OOx
Olx
02x
03x
04x
05x
06x
07x
lOx
llx
12x
13x
14x
15x
16x
17x

NUL
BS
DLE
CAN

ENQ
CR
NAK
GS

BEL
SI
ETB
US

---------------SOH

HT
DCI
EM

STX
LF
DC2
SUB

ETX
VT
IX3
ESC

C
K
S

D
L
T

I
c
k

(
0

I
9
A
I
Q
Y
a

8
@

P
X
grave
h
p
x

EaT
FF
DC4
FS
$

ACK
SO
SYN
RS
&

<
J

R
Z
b

F
N
V

]

1\ (t)

e
m
u

f
n
v
'" (ESC)

E
M

------------._----------_.-

0
W
(+-)
g
0

,~~. ~

Characters inside parentheses are ASCII-I 963 Standard.

NUL
SOH
STX
ETX
EaT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI

Null
Start of Heading
Start of Text
End of Text
End of Transmission
Enquiry
Acknowledge
Bell
Backspace
Horizontal Tabulation
Line Feed
Vertical Tabulation
Form Feed
Carriage Return
Shift Out
Shift In

OLE
DC]
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
DEL

A-I

w
DEL
...

Data Link Escape
Device Control I
Device Control 2
Device Control 3
Device Control 4
Negative Acknowledge
Synchronous Idle
End of Transmission Block
Cancel
End of Medium
Substitute
Escape
File Separator
Group Separator
Record Separator
Unit Separator
Delete (Rubout)

~--

Graphic
subsets
95
64

APPENDIX B
USING THE COMPILER

This appendix explains how to access FORTRAN-IO and how to make use of
the
information it provides.
You should be familiar
with the
FORTRAN-IO language and the DECsystem-lO TOPS-IO monitor.

B.l

RUNNING THE COMPILER

The command to run FORTRAN-IO is:
.R FORTRA
ThE! compiler responds with an aster isk (*) and is then ready to accept
a command string.
A command is of the general form:
object filename, listing filename=source filename(s)
You are given the following options:

B.l.l

'rhe filenames can be fully specified SFD paths.

You may specify more than one input file in the compilation
command string.
These files will be logically concatenated
by the compiler and treated as one source file.

Program units need not be terminated at file
may consist of more than one file.

If no object filename is
file is generated.

If no listing filename is specified, no listing is generated.

If no extension is given, the defaults are
.LST
.REL
(relocatable binary),
and
.FOR
(source)
respective files.

specified,

boundaries

relocatable

and

binary

(listing) ,
for
their

Switches Available with FORTRAN-IO

Switches to FORTRAN-IO are accepted anywhere in the command string.
They are totally position- and file-independent.
Table B-1 lists the
switches.

B-1

USING THE COMPILER
Table B-1
FORTRAN-IO Compiler Switches
Switch

Defaults

Meaning

1-----------+----------------------------------+-----------

CROSSREF

Generates a file that can be input to
the CREF program

OFF

DEBUG

(See Section B.l.l.l.)

OFF

EXPAND

Includes the octal-formatted version of OFF
the object file in the listing.

INCLUDE

Compiles a D in card column 1 as
as space.

OFF

KAla

Compiles code to run on a KAla
processor.

Compilation
processor

KIlO

Compiles code to run on a KIlO
processor.

Compilation
processor

LNMAP

Produces a line number/octal location
map in the listing only if /MACROCODE
was not specified.

OFF

MACROCODE

Adds the mnemonic translation of the
object code to the listing file.

OFF

NOERRORS

Does not print error messages
on the terminal.

OFF

NOWARNINGS

Does not output warning messages.

OFF

OPTIMIZE

Performs global optimization.

OFF

SYNTAX

Performs syntax check only.

OFF

L - -_ _ _ _ _ _ _- L -__________________________________________________________________________ . _______________. _____ _

Each switch must be preceded by a slash (/).
Switch names need only
contain
those letters that are
required
to make the switch name
unique.
You are encouraged to use at least three letters
to prevent
conflict with switches in future implementatio~s.
Example
.R FORTRA
*OFILE,LFILE=SFILE/MAC,S2FILE
The /MAC switch will cause the MACRO
S2FILE to appear in LFILE.LST.

code

equivalent

SFILE

and

If you do not specify a processor (KAla or KIlO switch), the code will
be compiled
for
the processor type on which the compilation occurs.
The processor type of the code in the object file
and
all
switches,
used or implied, are printed at the top of each listing page.

B-2

USING THE COMPILER
B.l.l.l The /DEBUG Switch - The /DEBUG switch tells FORTRAN-IO to
compile a series of debugging features into your program.
Several of
these features are specifically designed to be used with FORDDT.
Refer
to Appendix E for more information.
By adding the modifiers
listed in Table B-2, you can include specific debugging features.
Table B-2
Modifiers to /DEBUG Switch
Modifiers

Meaning

:DIMENSIONS

Generates dimension information in .REL
FORDDT.

: 'rRACE

Generates references to FORDDT required
for
its
trace features (automatically activates :LABELS).

:LABELS

Generates a label for each statement of the
form
"line-number
L." (This option may be used without
FORDDT. )

:INDEX

Forces DO LOOP indices to be stored at the
beginning of each iteration rather than held in a
register for the duration of the loop.

: BOUNDS

Generates the bounds checking code for
all array
references.
Bounds
violations
will produce
run-time error messages.
Note that the technique
of specifying dimensions of 1 for
subroutine
arrays will cause bounds check errors.
(You may
use this option without FORDDT.)

:NONE

Do not include any debug features.

:ALL

Enable all debugging aids.

file

for

---------------------

The format of the /DEBUG switch and its modifiers is as follows:
/DEBUG:modifier
or
/DEBUG: (modifier list)
Options available with the /DEBUG modifiers are:
1.

No debug features - Either do not specify the
or include /DEBUG:NONE.

All debug features - Either /DEBUG or /DEBUG:ALL.

Selected features - Either a
i .e •,
/DEBUG:BOU/DEBUG:LAB
or a list of modifiers
/DEBUG: (BOU,LAB, ... )

B-3

series

/DEBUG

modified

switch

switches:

USING THE COMPILER
4.

(if you wish all but one or
Exclusion of features
modifiers and do not wish to list them all, you JIlay use
prefix "NO" before the switch you wish to exclude) .
exclusion of one or more features implicitly includes all
the
same
i •e . ,
/DEBUG:NOBOU
others,
is
/DEBUG: (DIM,TRA,LAB,IND) .

two
the
The
the
as

If you include more than one statement on a single line, only the
first statement will receive a label
(/DEBUG:LABELS) or FORDDT
reference (/DEBUG:TRACE).
(The /DEBUG option and the /OPTIMIZE option
cannot be used at the same time.)
NOTE
If a source file contains line sequence
numbers that occur more than once in the
same subprogram, the
/DEBUG
option
cannot be used.
The following formulas may be used to determine the increases in
program size that will occur as a result of the addition of various
/DEBUG options.
:DIMENSIONS

For each array, 3+3*N words where N is the number
of dimensions, and up to three constants for each
dimension.

:TRACE

One instruction per executable statement.

:LABELS

No increase.

:INDEX

One instruction
per
instruction for some
index of the loop.

inner
of the

loop
plus
one
references to the

:BOUNDS

For each array,
DIMENSIONS:.

formula

the

same

For each reference to an array element, use 5+N
words where N is the number of dimensions in the
array.
If
you
do
not
specify
:BOUNDS,
approximately 1+3*(N-l) words will be used.

B.l.2

COMPIL-Class Commands

You can invoke FORTRAN-IO by using COMPIL-class commands.
These
commands cause the monitor to run the COMPIL program, which interprets
the command and constructs new command strings for the system program
actually processing the command.
When both FORTRAN-IO and F40 are
present in your DECsystem-lO system, you can specify which compiler is
to be us e.d by ad din g the s wit c h e s / FlOor / F 4 0 tot h e follow i n g
commands:
COMPILE
LOAD
EXECUTE
DEBUG

B-4

USING THE COMPILER
Example
.EXEC ROTOR/FlO
'rhe compiler switches KA, KI, OPT, CREF, and DEBUG may be
specified
directly in COMPIL-class commanus and nay :)e used globally or locally.
Example
.EXECUTE/CREF/KA/FlO PI.FOR,P2.FOR/DEBUG:NOBOU
The other compiler switches must be passed
specific source file.

parentheses

for

each

Commands

Manual

for

Example
.EXECUTE Pl.FOR(M,I)
Refer to
the
DECsystem-lO
further information.

B.2

Op~rating

System

READING A FORTRAN-IO LISTING

When you request a listing from the FORTRAN-lO compiler,
the following information:

contains

A printout of the source program plus
an
internal
sequence
number
assigned to each line by the compiler.
This internal
sequence
number
is
referenced
in
any error
or
warning
messa~es generated during the compilation.
If the input rile
is 1 ine-sequenced, the number from the [ile i~3 w;ed.
If code
is
added
via the INCLUDE statement, all INCLUDEd lines will
have an asterisk (*) appended to their line-sequence number.

A summary of the names and
relative
octal)
of
scalars
and
arrays
in
compiler generated variables.

All COMMON blocks and the relative locations
the variables in each COMMON block.

A listing of all equivalenced variables or arrays
relative locations.

A listing of the subprograms referenced
(both
and FORTRAN-lO defined library functions).

A summary of temporary locations generated by the compiler.

A heading on each page of the listing containing the
program
unit
name (MAIN., program, subroutine or function, principal
entry), the inpu t. filename, the 1 ist of compiler
swi tches,
and
the
date
and
time of compilatjon.
Whether a specific
processor switch (/KAlO, /KIlO) was used
and
the
processor
for
which
the
code was generated is also at the top of the
listing page.

If you used the /MACRO switch, a
mnemonic
printout
of
the
generated
code (in a format similar to MACRO-IO) is appended
to the listing.
This section has four fields:

B-5

program locations
(in
the source program plus
(in

octal)
and

user

their
defined

USING THE COMPILER
LINE: This column contains the internal sequence number
of the line corresponding to the mnemonic code.
It
appears on the first of the code sequence associated
with
that
internal sequence number.
An asterisk
indicates a compiler i~s~rted line.
LOC: The relative location in the object program of the
instruction.
LABEL:
Any program or compiler
0enerated
label.
Program labels have the letter IIpll appended.
Labels
generated by the compiler are followed by the letter
"M".
Labels generated by the compiler and associated
with the /DEBUG:LABELS switch consist of the internal
sequence number followed by an "L".
GENERATED CODE:

The MACRO-IO mnemonic code.

If you used the /LNMAP switch and did NOT use the /MACRO
switch, a line number/octal location map is appended to the
listing. This section lists the line numbers in increments
of 10 on subsequent lines and each number from 0 throu0h 9
for each line in adjacent columns.
The numbers GPpearing
inside the matrix are the relative octal locations of the
statements in the FORTRAN program unit.
For example, to find
the relative octal location of line number 001043, find the
row marked 001040 and then column 3 on that line. The number
in that place is the desired relative location. This listing
can be very large and sparse for line-numbered files with
large increments, such as those produced by SOS.
NOTE
One FORTRAN line
can
produce
multiple
octal
locations.
In this case the line number map lists
only the first location.

A list of all argument blocks generated by the compiler.
A
zero argumer1t dppears first followed by argument blocks (or
subroutine calls and function references (in order of their
appearance in the program).
Argument blocks for all I/O
operations follow this.

10.

Format statement listings.

11.

A summary of errors
during compilations.

B.2.1

detected

warning

messages

issued

Compiler Generated Variables

In certain situations the compiler will generate internal variables.
Knowing what these variables represent can help you read the lnaceo
expansion. The variables are of the form:
.letter digit digit digit digit
i.e., .SOOOI

B-6

USING THE COMPILER
where:
Letter

Function of Variable

Arithmetic statement function formal parameters.

Result of
a
DO LOOP
initial
value expression
parameter of an adjustably dimensioned array.
Result of a common subexpression (see Section
or constant computation (C.2.l.3).

.
'

Temporary storage for expression values.

Result of
(C.2.l.2) .

Result of the DO LOOP step size expression of
iteration count .for a loop.

reduced

operator

C.2.l.l)

expression

strength

computed

You may find these variables on the listing under SCALARS and ARRAYS .

The following example shows a listing where
pointed out •

.
'

B-7

all

these

features are

Name of
Program

EAIN.

Name of
Source File

Compiler
Version
FCF.TFAN V. 5+
( 515) /KI/M

TIMl.FOR

19-NOV-76

15:00

PAGE 1

1 Lero

Code equivalent included
code was compiled for a KI processor

en
I

CX)

00001
00002
00003
00004
00005
00006
00007
00008
00009
00010
00011
00012
00013
00014
C0015
00016
00017
00018
00019

IMPLICIT INTEGER (A-Z)
DIMENSION A(100,200) ,B(100,200)
SU~ll=O

100

;:;U[\'12=0
DO 100 J=1,200
DO 100 1=1,100
Kl=I*J
IF ((\1 .LT. 500 .OR. Kl .CT. 1500) Kl=O
A(I,J)=Kl
K2=I+J
IF (1\2 .LC'. 100 .OR. K2 .EQ. 200 .OR. K2.EQ.300)
o(I,J)=K2
Sml1=SUMl+Kl
SUt-i2=SUM2+K2
CONTINUE

TYPE 10,SUMl,SUM2
FORMAT(7H SUMl= ,I9,10H
END

SUM2= ,19)

Cfl
H

:z:

GJ
1-3
::;::

K2=K2+1

tT1

3:
'"d
H

L'
CTJ

:::v

SUBPROGRAMS CALLED
The relative address of each variable is given
cr~r~oc

...., \...o&.lJ...JC"l.L'"""

~~"

C'1.1."4 J.J

~OD~VC

C'l.~\'.L\.Cl.J..

n*n

t..J

t;'vnr TrTIT'

.LJ.t\,'cLJ..L.,-,".L.L

n~t;'T~TmT(,\~
V~~~"~~~V"

IIQ.II
"0

"1('\

l."tv

L,t;'t;'t;'Ot;'''1f''t;'n
.L\..LI.L

.LJ J.\.LJ 1."4

'-".LJ L.I

fCOIDPiler generated variable
*Kl
.SOOOO

116104

*SUM2

2
116105

*J
*1

47042
116106

A
*K2

47043
116107

.SOOOI
*SUMI

Internal sequence number on first instruction that goes with this line
octal displacement of instruction
tJj

LINE

LOC

LABEL

GENERATED CODE

2,J

r'iOVE

2, [777634000001]

MOVE
H1ULI

3,J
3,0 (2)
3,Kl
3,764
3,2734

JSP

21'1:

3M:

4M:

HRRZM

Ul.·~l.J

1
2
3
4

12
13
14
15

SETZE
MOVEM
MOVE
HLREM

"li,V"
16,RESET.
0,0
2,SUMI
2, SUr-l 2
2, [777470000001]
2, .SOOOO

Tt;'f"r

(f)

Z
G')

116103
116110

MOVE~1

CAlL
CAlLE

t-3

::r:
[:l:]

o
::s:
~

t'"'
tlJ

:::0

16
17
20

6~1:

["lAIN.

TIlvll. FOR

10
11
tJ:l
I
~

22
23
24
25
26
27
30
31
32
33
34
35

JEST
JRST

O,6t1

SETZS

4,K1

compiler generated label

FORTRAN V. 5 (515) /KI/M

12-

36
37

iViOVEI
I [';lUL
ADDI
MOVE
l·lOVCX
r10Vf
ADDI
MOVCiJl
MOVE
CAlL
CAIN
JRST

47
50

15:00

PAGE 1-1

en
H

5,14~

f-3

::r:

5,310
0,8M

n
0

:s:

5,454

'"d
H

81-1 :

AGS

3,K2

MOVEI
IMUL
ADCI
MOVE
nOVC~'l

3,144
3,J
3,0 (2)
5,K2
5,B-145(3)

ADeM
ADDM

5, Sm'l2

t'"
M
~

7M:

45
46

3,144
3,J
3,0 (2)
4,K1
4 ,A-145 (3)
3,J
3,0 (2)
3,K2
5,K2

9~i :

40
41
42
43
13
14
15

19-NOV-76

5M:

CAIN
11

0,5M

4,smn

10CP:_

prograJ.1 label
AOBJN
AOS
AGSGE
JRST

2,4M
2,J
0, .SOOOO

o, 3~/l

52
53
54
55
56

MOVEI
PUSHJ
HOVEl
PUSHJ
MOVEI

16,10M
17,OUT.
16,1111
17,IOLST.

PUSH.)

17:CXIT.

function and subroutine argument blocks

ARGUMENT BLOCKS:
60
61
62
63
64
65
66
67
70
71
72
73

tJj

I
f--'
I--'

16,lM

1H:
10M:

0, ,0
0, ,0
777773, ,0
0,,777777
0, ,0
0, ,0
34G,,10P

C
If.l

C, ,7
C, ,0

11M:

1100, , SUtll
1100, ,SUM2
4000,,0

I-:!

::r::
tt:!

n
o

MAIN.

'TIt'll. FOR

FORTRAN V.5(515)

/KI/M

19-NOV-76

15:00

PAGE 1-2

I-d
H

l'
M
~

FORMAT STATEMENTS (IN LOW SEGMENT):
18

HAIN.

116111
116112
116113
116114
116115
11Gl16
116117

lOP:

(7h 5

UM1=
, 19, 1

OE
5UM2
, 19

[ NO ERRORS DETECTED

summary of detected errors

t'lAIN.

tJ:l
I
I--'
N

00001
00002
00003
00004
00005
00006
00007
00008
00009
00010
00011
00012
00013
00014
00015
00016
00017
00018
00019

TH11. FOR

FO~TRAN

V.5(515) /KI

19-NOV-76

15:01

PAGE 1

IMPLICIT INTEGER (A-Z)
DIMENSION A(100,200) ,B(100,200)
SUMl=O
SUM2=0
DO 100 J=1,200
DC 100 1=1,100
Kl=I*J
IF (Kl .LT. 500 .OR. Kl .GT. 1500) Kl=O
A(I,J)=Kl
K2=I+J
I F (K 2 . E C' • 1 0 0 . 0 R • K2 • E Q • 2 0 0 . 0 R. K 2 . EQ. 3 0 0 ) K2 = K2 + 1
B(I,J)=K2
SUr-ll=SUMl+Kl
SUM 2 = SUM 2 + ~< 2
CONTINUE

100
C

TYPE 10,SUMl,SUM2
FORMAT(7H SUMl= ,I9,10H
END

en
H

Z
G1
f-3
..,..,

SUM2= ,19)

t'I:I

n
o

3:
t-c:1

SUBPROGRAMS CALLED

L'
tr1
~

SCALARS AND ARRAYS [ "*" NO EXPLICIT
*Kl
.SOOOO

1
116104

*SUM2

2
116105

LINE NUMBER/OCTAL LOCATION MAP

*J
*1

DEFINITIO~

47042
116106

II 0

-0

A
*K2

NOT REFERENCED ]
47043
116107

.SOOOI 116103
*SUMI
116110

line number may request with /LNMAP switch

. 0
1
2
3
4
6
8
5
7
9
-------.-----------------------------------------------------------------------------00000
00010
~1A

IN.

. 26

11
52

21
56

[ NO ERRORS DETECTED ]
line number 11 starts at octal location 31 (from the
previous listing, notice that line 11 uses locations
31 through 36 but only the first location is shown
here)

MAIN.

TItvll.FOR

FORTRAN V. 5 (515) /KI/OPT/M 19-NOV-76

15:00

PAGE 1

c
en
H

GJ
tJj

.......
w

00001
00002
00003
00004
oe005
00006
00007
00008
00009
00010
00011
00012
00013
00014
00015
00016
00017
00C18
00019

IHPLI CIT IWfECER (A-Z)
DIMENSION A(100,200) ,8(100,200)
SUMl=O
SUr-!2=O

DO 100 J=1,200
DO 100 1=1,100
Kl=I*J
IF (Kl .LT. 500 .OR. Kl .GT. 1500) Kl=O
A(I,J)=Kl
K2=I+J
IF (K2 .EQ. 100 .OR. K2 .EQ. 200 .OF. K2.EQ.300) K2=K2+1
8(I,J)=K2
sur·ll=SU~ll +K 1
SDr12=SUM 2+K2
100
C
10

COt~TINUE

TYPE 10,SUMl,SUM2
FORr1AT (7H SUMl= .I9,10H
END

sm·12= ,19)

1-3

::r:
M

0
3:
t-c;
H

L'
t!J
~

SUBPPOGRAMS CALLED
SCALARS AND ARRAYS [ 11*11 NO EXPLICIT DEFINITION

"%11 NOT REFERENCED]
optimizer created variables

*Kl
A
.00001

1
47045
116111

E
2
.SOOOl 116105
*K2
116112

t ..

.ROOOI 47042
.SOOOO 116106
*su~n
116113

+ 47043
.ROOOO
*SUM2
116107

*J
*1

47044
116110

optlmlzer created varlables

LINE

LOC

LABEL

.......
,j:::.

JFCL
JSP

SETZB
t-10VEI
t·jOVEM
MOVNI
6
5
hOVEl
7
MOVErv!
10
optimizer created statement
4
*

4
S

6
*

12
13

14
15
16
17

0,0
16,RESET.
0,0
10,11
12,144
12, .hOOGl

7,1
7,1
12, .SOOOO

4M:
~10VE

Cf.l
H

0
1
td
I

GENERATED COCE

r'10VE

6,7
2, [777634000001]

5M:
MOVEI
ADD
~10VE

CAlL
CAlLE

4,0 (2)
4,.ROCOl
5,6
£),764
5,2734

GJ
f-3

R
n
0

t-'

t:j

::0

JRST
Jf\S7

20
21
8

.t...t..

7rv! !

MAIN.

TIMl.FOR

24
25
26
27
30
31

tJ:1

')')

FORTRAN V. 5 ( 515) /KI/OPT/M 19-NOV-76
tvl0VEI

5,0

MOVEM
MOV£:
ADDI
CAIE
CAIN
JRST

5,A-145(4)
3,7
3,0 (2)
3,144
3,310
0,9M

CAIN

3,454

ADDI

3, 1

10M:

9M:

8£J) :

'") /I

ADD

35
36
37

ADD
ADD

3,B-145(4)
11,5
10,3
6,7

AOBJN
r.iOVEI
ADDiVl

2,5M
12,144
12,.FOOOI

ADDI
AOSG[
JRST

7,1
0, .SOOOO
0,4M
11 , SU~ll
10, SUfvl2
5,Kl
3,K2
16,11M
17,OUT.

*
*
*
*

.J":t

40
41
42
43
44
45
46
47
50
51
52

PAGE 1-1

Cfl
H

z()
f-3

>-<

E;j

MOVEtvl
13
14

15:00

6r-1:

f-'
U1

0,7M
0,6M

lOOP:

n
0

~
H

t-t

tT.1

Ifvl :

MOVE~1

MOV£:r-i
MOVEM
MOVEM
MOVEI
PUSHJ

!:U

*
19

53
54
55

tvlOVEI
PUSHJ

16,12M
17,IOLST.

MOVEI
PUSHJ

16,3M
17,EXIT.

2M:

56
ARGUMENT BLOCKS:
57
60
61
62
63
64
65
66
67
70
71
72

3M:
11M:

12M:

0, ,0
0, ,0
777773,,0
0,,777777
0, ,0
0, ,0
340,,10P
0, ,7
0, ,0
1100, ,SUMl
1100, ,SUM2
4000,,0

Cfl

ttl

::c:

0'\

tr:1

I
I-'

MAIN.

TIM1.FOR

FORTR/I,N V.5(515)

/KI/OPT/M 19-NOV-76

15:00

PAGE 1-2

o
~
H

FORMAT STATEMENTS (IN LOW SEGMENT):
18

MAIN.

116114
116115
116116
116117
116120
116121
116122

lOP:

(7H S

ur-a=
, I9, 1
OH
SUM2
,19

[ NO ERRORS DETECTED

t'-1
tr:1
::0

USING THE COMPILER
B.3

ERROR REPORTING

If an error occurs during the initial pass of the compiler (while
the
actual
source code is being read and processed), an error message is
printed on the listing immediately following the line
in which the
error occurred.
Each error references the internal sequence number of
the incorrect line.
The error messages along with the statement in
error are output to the user terminal.
For example:
.EXECUTE DAY.FOR
FORTRAN:DAY
01300
?FTNNRC LINE:01300
01500 100
?FTNMSP LINE:01500
01600 ?
?FTNICL LINE:01600

Kl
STATEMENT NOT RECOGNIZED
CONTINE
STATEMENT NAME MISSPELLED
ILLEGAL CHARACTER C IN LABEL FIELD

?FTNFTL MAIN.
LINK:
LOADING
[LNKNSA NO START ADDRESS]

3 FATAL ERRORS AND NO WARNINGS

EXIT
If errors
appear in
output to
reference

B.3.l

are detected after the initial pass of the compiler,
they
the list file after the end of the source listing.
They are
your terminal without the statement in error, but they may
its internal sequence number.

Fatal Errors and

W~rning

Messages

There are two levels of messages, warning and fatal
error.
Warning
messages are preceded by "%" and indicate a possible problem.
The
compilation will continue, and the object program will probably be
correct.
Fatal errors are preceded by a "?".
If a fatal error is
encountered in any pass of the compiler, the remaining passes will not
be called.
Additional errors that would be detected in later compiler
passes may not become apparent until the first errors are corrected.
It
is not possible to generate a correct object program for a source
program containing a fatal error.
The format: of messages is
?FTNXXX LINE:n text
or
%FTNXXX LINE:n text
where:
?
%

FTN
XXX
LINE:: n
text

fatal
warning
FORTRAN mnemonic
3-letter mnemonic for the error message
line number where error occurred
explanation of error

B-17

USING THE COMPILER
The printing of fatal errors and warnin~ messages on your terminal can
be suppressed by the use of the /NOERRORS switch; however, messages
will still appear on the listing.
The /NOWARNINGS switch will
suppress warning messages on both user terminal and listing.

B.3.2

Message Summary

At the end of the listing file and on the terminal, a message summary
is printed after each program unit is com~iled. This message has two
forms:
1.

when one or more messages were issued
?FTNFTL}
{ ?FTNWRN name NO/number FATAL ERRORS AND NO/number WARNINGS
or

when no messages were issued
name [NO ERRORS DETECTED]

where name is the program or subprogram name.
([NO ERRORS DETECTED]
appears on the listing only.) Appendix G is a complete list of fatal
errors and warning messages.

B.4

CREATING A REENTRANT FORTRAN PROGRAM WITH LINK-IO
-.---.----------------

To produce a sharable program from the .REL file,
such
give either one of the following commands to LINK-IO:
1.

/SEG:DEFAULT MAIN/G

jOTS:NONSHAR MAINjG

The resulting core image can be SSAVEd or the
used to produce a .SHR file.

B-18

jSSAVE

MAIN.REL,

switch

can

APPENDIX C
WRITING USER PROGRAMS

This appendix
is a guide
for
writing effective programs
with
FORTRAN-IO.
It contains techniques for optimization, interaction with
non-FORTRAN programs, mixing oi FORTRAN-IO and
F40 object programs,
and other useful programming hints.

C.I

GENERAL PROGRAMMING CONSIDERATIONS

The
following
paragraphs describe programming considerations you
should observe when preparing a
FORTRAN program to be compiled by
FORTRAN-IO.

C.I.l

Accuracy and Range of Double-precision Numbers
--_.--~- -~- -~------.-------------.--

Floating-point and real numbers may consist of up to 16 digits
in a
double-precision mode.
Their range is specified in Chapter 3, Section
3.2 of this manual.
You must be careful when testing the value of a
number within the specified range since, although numbers up to 10**38
may be represented, FORTRAN-IO can only test numbers of up to eight
significant digits (REAL precision) and 16 significant digits (DOUBLE
precision) .
floating-point computation
You must also be careful when testing the
for a result of O.
In most cases the anticipated result, i.e., 0 will
be obtained;
however, in some cases the result may be a
very small
number
that approximates
o.
Such an approximation of o will cause
tests within statements, i.e., an arithmetic IF, to fail.

C.l.2

Writing FORTRAN-IO Programs for Execution On Non-DEC Machines
-------------

If you prepare a program to run on both a DECsystem-lO computer and
non-DIGITAL machine, you should:

Avoid using the non-ANSI standard features of FORTRAN-IO, and

Consider the accuracy and
size of the numbers
non-DIGITAL machine is capable of handling.

C-l

that

the

WRITING USER PROGRAMS
C.l.3

Using. Floating-Point DO Loops

FORTRAN-IO permits you to employ non-integer single- or doubleprecision numbers as the parameter variables in a DO statement. This
enables you to generate a wider range of values for the DO loop index
variables,
which
may,
in turn, be used inside the loop for
computations. Be sure to consider the loss of precision that may
occur.

C.l.4

Computation of DO Loop Iterations

The number of times through a DO loop is computed outside the loop and
is not affected by any changes to the DO index parameters within the
loop. The formula for the number of times a DO loop is executed is:
DO 10 I=MI,M2,M3
MAX

(1, {{M2-M1)/M3)+1)=Number of cycles

The values of the parameters MI, M2, M3 may be of any type;
however,
you must consider the foregoing formula, particularly when using
logicals. One pass through each DO loop is always performed EVEN IF
THE RESULT OF THE FOREGOING CALCULATION IS LESS THAN OR EQUAL TO ZERO.

C.l.5

Subroutines - Programming Considerations
.. _ - -

Consider the following items when preparing and executing subroutines:
1.

During execution, no check is made
number of parameters was passed.

see

the

proper

If the number of actual arguments passed to a subroutine is
less than the number of dummy arguments specified, the values
of the unspecified arguments are undefined.

If the number of actual arguments passed to a subroutine is
greater than the number of dummy arguments given, the excess
arguments are ignored.

If an actual parameter is a constant and its corresponding
dummy argument is set to another value, all references made
to the constant in the calling program may be changed to the
value of the dummy argument.

No check is made to see if the parameters passed are of the
same type as the dummy parameters.
If an actual parameter is
a constant and the corresponding dummy is of type real, be
sure to include the decimal point with the constant.
If the
dummy is double-precision, be sure to specify the constant
wit.h a "0".
Examples
If the function F(A) is called by inputting F(2)
and A is
type real,
F interprets the integer 2 as an unnormalized
floating-point number.
In this instance, F{A)
should be
called with F(2.0).
Similarly, if the function Fl(D)
is
Fl(2.5)
and 0 is double-precision,
C-2

called by inputting
Fl assumes that its

WRITING USER PROGRAMS
parameters have been specified with two words of precision
and picks up whatever follows the constant 2.5 in core.
The
proper method is to usc Fl (2. 5DOO) .
NOTE
You are given no notice
if any of the
described in items 1,2,3,4, and 5 occur.

C.l.6

situations

Reordering of Computations

Computations that are not enclosed within parentheses may be reordered
by the compiler.
Sometimes
it
is necessary to use parentheses to
ensure proper results from a specific computation.
For example, assuming that
1.

RLI represents a large number such that RLI*RL2 will cause an
overflow condition, and

RSI is a very small number,
sequence

i.e., less than

the

program

A=RSI*RLI*RL2
B=RS2*RL2*RLI

will not produce an overflow when evaluated left
to
right,
since the first computation in each expression, i.e., RSl*RLl
and RS2*RL2, will produce an interim result that
is smaller
than either large number (RLI or RL2).
However, the compiler will recognize RLI*RL2 as a common subexpression
(see Section C.2.1.1) and generate the following sequence:
temp
A
B

RLI*RL2
RSI*temp
RS2*temp

The computation of temp will cause an overflow.
You should write the program as follows to
results are obtained:

ensure

that

the

desired

A=(RSI*RLl)*RL2
B=(RS2*RL2)*RLI

Computations may be reordered even when
selected .

C-3

global

optimization

not

WRITING USER PROGRAMS

c.1 . 7

Dim e n s ion in g

0 f

For mal A~_ r a ¥_~

When you specify an array as a formal parameter to a subprogram unit,
you must
indicate
to
the compiler that the parameter is an array.
Dimension the array in a specification statement.
This
is
the only
way the compiler is able to distinguish a reference to such an array
from a function reference.
Designating the array with a dimension of
1 is a common practice.
Example
SUBROUTINE SUBl(A,B)
DIMENSION A(l)
There are disadvantages to
using
dimension
information provided
specifically:
1.

the above
technique
is not adequate
in

because
the
some cases,

Reading or writing the array by name
DIMENSION ARRAY (10)
READ (1) ARRAY
The above is a binary read that
ARRAY.

will

read

ten

words

into

SUBROUTINE SUBl(A)
DIMENSION A(l)
READ(l)A
This binary read will cause one word to be read into A.
2.

Reading the array as a format
SUBROUTINE SUB2 (FMT)
DIMENSION FMT(l)
READ (l,FMT)
This will cause one word of the array FMT to be written
with the characters read from the record on unit 1.

over

When you use
the /DEBUG:BOUNDS compilation switch,
the dimension
information used is that which is specified in the array declaration.
SUBROUTINE DO IT(A)
DIMENSION A(l)
A(2)=0
The reference to A(2) will cause the out-of-bounds warning message
be generated.

C.2

FORTRAN-IO GLOBAL OPTIMIZATION

You have
the option of
invoking
the global
optimizer
during
compilation.
The optimizer treats groups of statements in the source
program as a single entity.
The purpose of the global optimizer is to
prepare a more efficient object program that produces the same results
as the original unoptimized program,
but
takes significantly less
execution time.
The output of
the lexical and syntactic analysis
phase of the compiler is developed into an optimized source program
equivalent
(in results)
to
the original.
The optimized program is
then processed by the standard compiler code generation phase.

C-4

WRITING USER PROGRAMS
C.2.1

Optimization Techniques

------

c.2.1.1
Elimination of Redundant Computations - Often
the
same
subexpression will
appe--ar-ln-morE~ than one computation throughout a
program.
If the values of the operands of such a
common expresslon
are not changed between computations, the subexpression may be written
as a separate arithmetic expression, and the variable representing its
resultant may then be
substituted where the subexpression appears.
This eliminates unnecessary recomputation of the
subexpression.
For
example, the instruction sequence:
A=B*C+E*F

H=A+G-B*C

IF((B*C)-H)

10,20,30

contains the subexpression B*C three times when it really needs to
computed only once.
Rewriting the foregoing sequence as:

T=B*C
A=T+E*F
H=A+G-T
DIF((T)-H)

10,20,30

eliminates two computations of the subexpression B*C from the
sequence.

overall

Decreasing the number of arithmetic operations performed in a
source
program by the elimination of common sUbexpressions shortens the
execution time of the resulting object program.

C.2.l.2 Reduction of Op~rator Str~!:!..9.!-~ - The time required to execute
arithmetic operations will vary according to the operator(s) involved.
The hierarchy of arithmetic operations according
to
the amount of
execution time required is:
MOST TIME

OPERA'l'OR
**

/
LEAST TIME

+,-

During program optimization,
the global
optimizer
replaces,
where
possible
(1),
some arithmetic operations that require the most time
with operations that require less time.
For
example,
consider
the
following DO loop that is used to create a table for the conversion of
from 1 to 20 miles to their equivalents in feet.
10

DO 10 MILES=1,20
IFEET(MILES)=5280*MILES

1. Numerical analysis considerations
cases where this is possible.

severely

limit

the

number

WRITING USER PROGRAMS
The execution time of the foregoing
loop would be shorter
if
the
time-consuming multiply operation, i.e., 5280*MILES, could be replaced
by a faster operation.
Since you increment MILES on each pass,
you
can replace the multiply operation by an add and total operation.
In its optimized form, the foregoing
sequence equivalent to:

loop

would

replaced

K=5280
DO 10 MILES=1,20
IFEET(MILES)=K
K=K+5280

In the optimized form of the loop, the value of K is set to
5280 for
the
first
iteration of
the
loop and is increased .by 5280 for each
succeeding iteration of the loop.
This foregoing situation occurs frequently in subscript calculations
that
implicitly contain multiplications whenever the size is two or
greater.

C.2.l.3 Removal of Constant Computa~io~ ~rom ~o~ - The
speed with
which
a given algorithm may be executed can be
increased
if
instructions and/or computations are moved out of frequently traversed
program sequences
into less frequently traversed program sequences.
Movement of code is possible only if none of
the arguments
in
the
items to be moved are redefined within the code sequences from which
they are to be
taken.
Computations within a
loop consisting of
variables or
constants that are not changed in value within the loop
may be moved outside the loop.
Decreasing the number of computations
made within a
loop greatly decreases the execution time required by
the loop.
For example, in the sequence:
10

DO 10 1=1,100
F=2.0*Q*A(I)+F

the value of the computation
2.0*Q,
once calculated on
the
first
iterations,
will
remain unchanged during the remaining 99 iterations
of the loop.
Reforming the foregoing sequence to:

QQ=2.0*Q
DO 10 1=1,100
F=QQ*A(I)+F

moves the calculation 2.0*Q outside
the
scope of
movement of code eliminates 99 multiply operations.

the

loop.

This

In addition, it is possible to
remove entire assignment
statements
from loops.
This action can be easily detected
from the macro
expanded listings.
The internal
sequence number
remains with
the
statement and appears out of order in the leftmost column of the macro
expanded listing (LINE).

C-6

WRITING USER PROGRAMS
C.2.l.4 Constant Folding_and Propagation - In
this
method
of
optimization,
expressions containing determinate constant values are
detected and the constants are replaced, at compile
time,
by their
defined or calculated value.
For example, assume that the constant PI
is defined and used in the following manner:

PI=3.l4lS9

X=2*PI*Y

At compile time, the optimizer will have used the defined value of
PI
to calculate the value of the
subexpression 2*PI.
The optimized
sequence would then be:

PI=3.l4IS9

X=6.28318*Y

thereby eliminating a multiply operation from the object code program.
The computation of determinate constant values at compile
time
is
termed
"folding";
the
use of the defined value of a constant for
replacement purposes throughout
a
program
sequence
is
termed
"propagation of
the constants."
The execution time
saved by the
foregoing type of compile time optimization is particularly important
when the modified instruction occurs in a loop.

C.2.I.S Removal of Inaccessible Code - The optimizer
detects
and
eli min ate san y cod e wit h i n~-sourcE~ p r og r am t hat can not be a c c e sse d .
In general, this will not happen since programmers do
not
normally
include such code in their programs;
however, inaccessible code may
appear in a program during the debugging process.
The
removal
of
inaccessible code by the optimizer will reduce the size of the object
program.
A warning message is generated for
each
inaccessible line
removed.

C.2.1.6 Global Register ~~~c_9_ti~!! -- During
the compilation of
a
source program, the optimizer controls the allocation of registers to
minimize computation time
in
the optimized object program.
The
allocation process
is designed
to minimize the number of MOVE and
MOVEM machine instructions that will appear
in the most
frequently
executed portions of the code.

C-7

WRITING USER PROGRAMS
C.2.l.7
I/O Optimization - Every effort
is made
to minimize
the
number of required calls to the FOROTS system.
This is done primarily
through extensive analysis of implied
DO loop constructs on READ,
WRITE,
ENCODE,
DECODE,
and REREAD st~tements.
The formats of these
special blocks are described
in Appendix
E.
These optimizations
reduce dthe
size of
the program (argument code plus argument block
size is reduced) and greately improve the performance of programs that
use implied DO loop I/O statements.

C.2.l.8 Uninitialized Variable Detection - A
warning
message
is
generated when a scalar variable is referenced before it has received
a value.

C.2.l.9 Test Replacement - If the only use of a DO loop index
is
to
reduce operator strength (D.2.l.2) and the loop does not contain exits
(GO TOs out of the loop), the DO loop index is not needed and can be
replaced by the reduced variable.
For example:
DO 10 1=1,10
K=K+7*I
CONTINUE

Reduction of operator strength and test replacement together transform
this loop into
DO 10 1=7,70,7
K=K+I
CONTINUE

This occurs frequently in subscript computation.

C.2.2

Improper Function References

Consider this statement:
P

= F(X) + Q(Y)

If:
1.

the evaluation of F(X) defines or changes the variables A, B,
and C, and

the evaluation of Q(Y) defines or changes the values of B, C,
and D,

then it is possible that different values of P could result, depending
on which
function
is evaluated
first.
Let's see how this works.
Let's assign some values (to begin with) to A, B, C, and D and define
the functions F(X) and Q(Y):
Let:
F (X) :
A
B

C
D

2.
3.
4.
5.

Q(Y) :

A
B

C
F

6.
7.
8.
D + 9.

C-8

C
D
Q

10.
11.
12.
A + 13.

WRITING USER PROGRAMS
Now play computer and evaluate P, calling first F(X), then Q(Y).
Now
re-evaluate
P,
calling Q(Y)
first, then F(X).
Notice that you got
different values for P because the variables A, B, C,
and
D changed
value depending on the order in which the functions were called.
(Our
answers were 33 when F(X) was called first and 36 when Q(Y) was called
first.)
The ANSI FORTRAN standard prohibits this kind of situation.
But the
compiler won't c~tch it unless you mention the affected variables in
the function call itself.
The compiler depends on strict adherence to
this rule.
There's a
strong possibility that you won't get the
results you want if you don't look for situations of this
type and
avoid
them.
Your best bet is to define your variables OUTSIDE the
function and not change them in the course of the evaluation of the
function itself.

Programming TechniSL~~~}oE__ ~~}ec_tiv~?ptiE1iza_00~

C. 2.3

Observe the following recommendations during the coding of a
FORTRAN
source program.
They will improve the effectiveness of the optimizer.

C.3

Do not use DO loops with an extended range.

Specify label lists when using assigned GO TOs.

Nest loops so that the innermost index is the
largest range of values.

Avoid the use of associated input/output variables.

Avoid unnecessary use of COMMON and EQUIVALENCE.

one

with

the

INTERACTING WITH NON-FORTRAN-IO
PROGRAMS AND FILES
- - - - -----,------_._------_.-

C.3.l

Calling Sequences

The following paragraphs describe the standard procedures for
DECsystem-lO subroutine calls.
1.

writing

Procedure

The calling program must load the right
accumulator
(AC)
16 with the address of
argument in the argument list.

The left half of AC 16 must be set to zero.

The subroutine is then called by a PUSHJ
AC 17.

The return will be made to the
after the PUSHJ 17 instruction.

If you use the /DEBUG:BOUNDS option of the
facility, the calling sequence must be
MOVEI l6,AP
PUSHJ l7,F

C-9

half
of
the
first

instruction

immediately
FOROTS

trace

WRITING USER PROGRAMS
where AP is the pointer to the argument list.
If you use
the trace facility, the word preceding the first word of
an entry point should have its name in SIXBIT.
2.

Re s t ric t ion s
a.

Skip returns are not permitted.

The contents of the pushdown stack located before the
address specified by AC 17 belong to the calling program;
they cannot be read by the called subprogram.

stack;
assumes that it has control of the
you must not create your own stack. The
FOROTS stack is initialized by:
FOROTS

ther~fore,

JSP 16,RESET.
or the library routine
CALL RESET.

C. 3.2

Accumul_at-.9~sage

The specific functions performed by accumulators (AC) 17,16,0,
are as follows:

and

Pushdown Pointer - AC 17 is always maintained as a pushdown
pointer.
Its right half points to the last location in use
on the stack, and its left half contains the negative of the
number of (words-I) allocated to the unused remainder of the
stack.
(A trap occurs when something is pushed into the next
to last location. The trap instruction may itself be a PUSHJ
on the KIlO processor, which uses the last location.)
A
positive left half is not permitted.

Argument List Pointer - AC 16 is used as the argument
pointer. The called subprogram does not need to preserve its
contents. The calling program cannot depend on getting back
the address of the argument list passed to the callee. AC 16
cannot point to the ACs or to the stack.

Temporary and Value Return Registers - AC
and 1 are used as
temporary registers and for returning values. The called
subprogram does not need to preserve the contents of AC
or
1 (even if not returning a value). The calling program must
never depend on getting back the original contents of the
data passed to the called subprogram.

Returning Values - At the option of the designer of a called
subprogram, a subroutine may pass back results by modifying
the arguments, returning a single-precision value in AC
or
a double-precision or complex value in AC
and 1. A
combination of the above may be used.
However,
two
single-precision values cannot be returned in AC 0 and 1,
since FORTRAN would not be able to handle it.

C-IO

WRITING USER PROGRAMS
5.

Preserved ACs - FORTRAN-IO FUNCTION subprograms preserve
2 through 15; subroutine subprograms do not.

ACs

The design of the called subprogram cannot depend on the
contents of any of the ACs being set up by the calling
subprogram, except for ACs 16 and 17.
Passing information
must be done explicitly by the argument list mechanism.
Otherwise, the called subprograms cannot be written in either
FORTRAN-IO or COBOL.

C.3.3

Argument Lists

The format of the argument list is as follows:
Arg count word
Arg list addr.---First arg entry
Second arg entry

Last arg entry
The format of the arg count word is:
bits 0-17
bits 18-35

These contain -n, where n is the
entries.
These are reserved and must be O.

The format of an arg entry is as
word) :
bits 0-8
bits 9-12
bit 13
bits 14-17
bits 18-35

follows

(each

number

entry

Reserved for future DEC development
now) .
Arg type code.
Indirect bit if desired.
Index field, must be 0 for present.
Address of the argument.

arg

single

(set

for

The following restrictions should be observed:

Neither the argument list nor the arguments themselves can be
on the stack. This restriction is imposed so that the stack
can be moved. The same restriction applies to any indirect
argument pointers.

The called program may not modify the argument list itself.
The argument list may be in a write-protected segment.
Note that the arg count word is at position -1 with respect
to the contents of AC 16. This word is always required even
if the subroutine does not handle a variable number of
arguments.
A subroutine that has no arguments must still
provide an argument list consisting of two words,
i.e., the
argument count word with a 0 in it and a zero argument word.

C-ll

WRITING USER PROGRAMS
Example
MOVEI 16,AP
PUSHJ 17,SUB

iSET UP ARG POINTER
iCALL SUBROUTINE
iRETURN HERE

iARGUMENT LIST
-3, ,0
A

AP:

iSUBROUTINE TO SET THIRD ARG TO SUM OF FIRST TWO ARGS
MOVE
ADD
MOVEM
POPJ

SUB:

C.3.4

iGET FIRST ARG
iADD SECOND ARG
iSET THIRD ARG
iRETURN TO CALLER

T,@O(16)
T,@l(16)
T,@2(16)
17,

Argument Types
Table C-l
Argument Types and Type Codes
Type Code

Description
~-----------------~----------------------~

FORTRAN Use

COBOL Use

~-------------.-----r--------------------r-----------------------------~

o
1
2
3

4
5
6
7

10
11
12
13
14
15
16
17

Unspecified
FORTRAN Logical
Integer
Reserved
Real
Reserved
Octal
Label
Double real
Not applicable
Double Octal
Reserved
Complex
Not applicable
Reserved
ASCIZ string

Unspecified
Not applicable
I-word COMP
Reserved
COMP-l
Reserved
Reserved
Procedure address
Not applicable
2-word COMP
Reserved
Reserved
Not applicable
Byte string descriptor
Reserved
Not applicable

L... _ _ _ _ _._ _ _ _ _ _ _ _ _ _ _--'---_ _ _ . _ _ _._. _ _ _ _ _ _ _ _ _ _ _ _ _ _ ' - -___________________- - - - _ _ _ _ _ _- - - '

Literal arguments are permitted, but they must reside
in a
writable
segment.
This is because the FORTRAN-IO compiler makes a local of all
non-array elements and copies all
formals back to the caller's
arguments.
All
unused type codes are reserved for future DIGITAL
development.

C-12

WRITING USER PROGRAMS
C.3.5

Description of

Arg~ments

The types of the arguments that may be passed are:
1.

Type a - Unspecified
The calling program has not specified the type.
The called
subprogra~s should assume that the argument is of the correct
type if it is checking types.
If several types are possible,
the called subprogram should assume a default as part of its
specification.
If none of the above conditions is true,
the
called subprogram should handle the argument as an integer
(type 2).

Type 1 - FORTRAN logical
A 36-bit binary value containing a or positive
.FALSE.
and negative to specify .TRUE ..

Type 2 -

specify

Integer and l-word-COMP

A 36-bit 2's complement signed binary integer.
4.

Type 4 - Real and COMP-l
A 36-bit DECsystem-lO format floating-point number.
bit a
bits 1-8
bits 9-35

sign
excess 128 exponent
mantissa

Type 6 - Octal
A 36-bit unsigned binary value.

Type 7 - Label and procedure address
A 23-bit memory address.
bits 0-12
bit 13
bits 14-17
bits 18-35

always ()
indirect flag

the address

Type 10 - Double real
A double-precision floating-point number for the CPU on which
code
is being executed, i.e., KA format on a KAla processor
and KI format on a KIlO processor.

Type 11 -

2-word CaMP

A 2-word

(72-bit)

word
word
word
word
9.

1,
1,
2,
2,

2's complement signed binary integer.

bit a
bits 1-35
bit a
bits 1-35

sign
high order
same as word 1, bit a
low order

Type 12 - Double octal
A 72-bit unsigned binary value.

C-13

WRITING USER PROGRAMS
10.

Type 14 - Complex
A complex number represented as an ordered pair of
36-bit
floating-point
numbers.
The first represents the real part,
and the second represents the imaginary part.

11.

Type 15 - Byte String Descriptor
The format of the byte string descriptor is:
word 1:
word 2:

ILDB-type pointer,
i.e.,
aimed at
the
preceding the first byte of the string
EXP byte count

byte

The byte descriptor may not be modified by the called
program.
The byte string itself must consist of a string of
contiguous bytes of uniform size.
The byte size may be any
number of bits from 1 to 36.
The byte count must be large
enough to encompass 256K words of storage, i.e., 24 bits for
I-bit bytes.
(See COBOL Program Reference Manual.)
12.

Type 17 - ASCIZ string
A string of contiguous 7-bit ASCII bytes left
justified on
the word boundary of the first word and terminated by a null
byte in the last word.
The length of the string may be
from
1 to 256K words.

C.3.6

Converting Existing MACRO-IO Libraries for use with FORTRAN-IO

The
following
sequence.

simple

example

illustrates

C-14

the

FORTRAN-IO

calling

MAIN.

EX1.FOR FORTRAN V.5(515) /KI/M

00001
00002
00003

AN EXAMPLE OF A CALL TO A SUBROUTINE

~ITH

PAGE 1

A VARIETY OF ARGUMENTS

DOUBLE PRECISION DP
l"'\TMt:'l\1CT(Yl\1

00004

00005
00006
00007
00008
00009
00010
00011
00012
00013
00014
00015
00016
00017

12:19

4-NOV-76

.&.....I ....... J. .....,u... ....,.L.'-..Il."

C
C
C
C
C
C

C
C

.LJ

111""\1
\

...LV}

THE ARGUMENTS ARE:
1. A REAL VARIABLE
2. AN ARRAY NAME
3. AN ARRAY ELEMENT
4. AN INTEGER VARIABLE
5. A DOUBLE PRECISION VARIABLE
6. AN OCTAL CONSTANT
7. A LITERAL

CALL SUBI (A, B, B(I), K, DP, "777,

~
H

t-3

'ABC')

[NO

(')

I
.......
VI

(f)

tr:I
~

SUBPROGRAMS CALLED

t-c1
~

SUBI

GJ
~

:J:::I

SCALARS AND ARRAYS [ "*" i'JO EXPLICIT DEFINITION - "%" NOT REFERENCED
DP

TEMPORARIES
.QOOOO 20

(f)

LINE

LOC

LABEL

GENERATED CODE
JFCL
JSP

0
1
2
3
4
S
6
7
10
11

MOVE
MOVEI
MOVEM
~10VEI

PUSHJ
MOVEI
PUSHJ

0,0
16,RESET.
0,0
2,1
2,B-l(2)
2,.QOOOO
16,2M
17,SUBl
16,lM
17,EXIT.

ARGUMENT BLOCKS:
12
13
14
IS

1M:
2M:

0, , 0
0, ,0
777771, ,0
200"A

~
H

8
H

Z
G)

(")

I
I-'

C/)

MAIN.

EX1.FOR FORTRAN V.S(S12) /KI/M

4-NOV-76

12:19

PAGE 1-1

M
:;d

0"1

"0
~

MAIN.

16
200"B
17
220".QOOOO
20
100"K
21
400"DP
22
300" [000000000777]
23
740" [4060S0320100)
[ NO ERRORS D£TEC'ft:D ]

MAIN.

EX1.FOR FORTRAN V.S(S12) /KI/M

00001
00002
00003

4-NOV-76

G)
~

::P

::s:

C/)

12:19

PAGE 1

SUBROUTINE SUBI (REALI, ARYNAM, ARYELM, INTI, DBLPRC, OCT, LIT)
DOUBLE PRECISION DBLPRC

()

I
I--'

00004
00005
00006
00007
00008
00009
00010
00011
00012
00013
00014
00015
00016
00017
00018
00019
00020
00021
00022
00023
00024
00025

DIMENSION ARYNAM (10)
C

AN EXAMPLE OF THE USE AND MODIFICATION OF FORMAL PARAMETERS
Xl
X2

REALI
ARYNAM

ARYELM

II
X4
12
13

INTI
DBLPRC
OCT
LIT

(J)

REALI = Xl
ARYNAM (J)
X2
ARYELM = X3
INTI = II
DBLPRC = CMPLX (X4, 0.0)
OCT
n 55
LIT = 'ZYXW'

:s
~
H
~
H

GJ
C

RETURN
END

Cf)
t'Ij

---.,I

'1J

SUBPROGRAMS CALLED

COMPLX.

~
~

Cf)

SCALARS AND ARRAYS
*LIT
DBLPRC
*INTI

1
6
14

TEMPORARIES
.AOOI6 21

[

*OCT
*13
*12

n*n

NO EXPLICIT DEFINITION 2
10
15

*X4
3
*REALI 11
*Xl
16

n%n

NOT REFERENCED
*ARYELM 4
12
*J
*11
17

*X3
5
*X2
13
ARYNAM 20

LINE

SUBI

LOC

LABEL

GENERATED CODE

636542,,210000

SUBl:
0
1
2
3
4
5

MOVEM
MOVE
MOVEt-1
MOVEI
MOVEM
MOVE

16,.AOO16
O,@O, (16)
O,REALI
1,@1(16)
1,ARYNAM
1,@2(16)

EXl.FOR FORTRAN V.5(512) /KI/M

4-NOV-76

12:19

PAGE 1-1
:8

n
I

I--'

10
11
12
13
14
16

MOVEM
MOVE
MOVEM
DMOVE
DNOVEM
MOVE
r<lOVEM
MOVE
MOVEM

1,ARYELM
2,@3(16)
2,INTI
4,@4(16)
4,DBLPRC
3,@5(16)
3,OCT
6,@6(16)
6,LIT

20
21
22
23
24
25
26
27
30
31
32

MOVEM
MOVE
ADD
MOVE
MOVEM
MOVEM
MOVEM
PUSHJ
MOVEM
FIX
MOVEM
MOVEM

MOVEM

O,Xl
7,J
7,ARYNAM
7,777777(7)
7,X2
1,X3
2,11
17,SNG.4
4,X4
3,3
3,12
6,13
O,REALI

6
7
10
11
12
13
14
15
16
17

~
H

t-3
H

CJ)

tIJ

!:O
IiJ
~

0
GJ
~

3M:

::t;:;

3:
CJ)

17
18
19
20
21
22
25

34
35
36
37
40
41
42
43
44
45
46
47
50
51
52
53
54
55
56
57
60
61
62
63
64
65

n
I

I--'
1.0

MOVE
ADD
MOVEM
MOVEM
MOVEM
MOVEI
MOVEI
DMOVEM
MOVEI
MOVEM
MOVE
MOVEM

3,J
3,ARYNAM
7,777777 (3)
I,ARYELM
2,INTI
5,0
5,0
4,DBLPRC
2,55
2,OCT
2, [552633053500]
2,LIT

MOVE
MOVE
MOVEM
MOVE
MOVEM
MOVE
MOVEM
DMOVE
DMOVEM
MOVE
MOVEM
MOVE
MOVEM
POPJ

16, .AOOI6
O,REALI
0,@0(16)
O,ARYELM
0,@2(16)
0,INT1
0,@3(16)
O,DBLPRC
0,@4(16)
O,OCT
0,@5(16)
O,LIT
0,@6(16)
17,0

2M:

ARGUMENT BLOCKS:

SUB1

0, , 0
66
0, ,0
67
1M:
[ NO ERRORS DETECTED

:8
~

t-3
H

c::

(f)

tI:l
:;0

'"C1

?::1
0

?::1

(f)

WRITING USER PROGRAMS
To convert existing MACRO-IO programs conveniently so that they will
still load and execute correctly when called from F40 or FORTRAN-lO:
1.

Transfer the initial entry sequence for a routine to
entry:

CAIA
PUSH l7,CEXIT.##

Change all returns to POPJ 17,0

These are the functions performed by the HELLO and GOODBY macros.
These macros
(available in the file FORPRM.MAC, part of the FOROTS
release) were successfully used to convert the library routines to run
with both F40 and FORTRAN-IO.
In addition, since the FORTRAN-IO compiler uses the indirect bits on
argument lists
(note that this permits shared, pure code argument
lists), it is essential for code that accesses parameters to take this
into account.
Specifically, sequences that obtained the values of
parameters through use of operations such as
HRRZ R,1(16)
to pick up the address of the second argument should be changed to
MOVEI R,@1(16)
The latter operation will work when interfacing
FORTRAN-IO.

with

either

F40

Refer to the previous example, which illustrates the code generated by
the FORTRAN-IO compiler, for specific details of how each argument is
accessed. Note that in the case of the formal array, it is the
address of the array that is accessed.

C.3.7

Mixing FORTRAN-IO and F40 Compiled Programs

Starting with version lA of LINK-lO, use of the switch /MIXFOR will
permit loading FORTRAN-IO and F40 programs.
This is achieved by
modifying the code while it is loaded.
This introduces extra code that results in a degradation of the
execution of programs so loaded.
This feature is provided as a
convenience for conversion. It is not intended to be used for other
than conversion assistance.

C.3.8

Interaction with COBOL-IO

The FORTRAN-IO programmer may call COBOL-IO programs as subprograms,
and, conversely, the COBOL programmers may call FORTRAN-IO programs as
subprograms.
In either of the foregoing cases, I/O operation must not be
in the called subprogram.

C-20

performed

WRITING USER PROGRAMS
C.3.B.l Calling FORTRAN-IO Subprograms from COBOL-IO Programs - COBOL
programmers
may
wr i te
subprograms
in
FORTRAN-IO to-use
the
conveniences and facilities provided by this language.
The COBOL verb
ENTER is used to call FORTRAN-IO subroutines.
The form of ENTER is as
follows:
ENTER FORTRAN program name

identifierl
}
literall
{ procedure namel

USING

[

{ i~entifier2}J .. .J
Iltera12
procedure2

The USING clause of the foregoing forms
names the data within the
COBOL
program that
is to be passed
to
the called
FORTRAN-IO
subprogram.
The passed data must be
in a
form acceptable to
FORTRAN-IO.
The calling sequence used by COBOL in calling a FORTRAN-IO
is:

subprogram

MOVEI 16, address of first entry in argument list
PUSHJ 17, subprogram address
If the USING clause appears
in the
ENTER statement,
the compiler
creates an argument list that contains an entry for each identifier or
literal in tbe order of appearance
in the
USING clause.
It
is
preceded by a word containing, in its left half, the negative number
of the number of entries in the list.
If no USING clause is present,
the argument list contains an empty word, and the preceding word is
set to O.
Each entry in the list is one 36-bit word at the form:

Bits O-B are always O.
Bits 9-12 contain a type code that indicates the USAGE
argument.

the

Bits 13-35 contain the address of the argument of the
first
word of the argument;
the address can be indexed or indirect.
Following is a description of the types, their codes,
how the codes
appear
in the argument list,
and
the locations specified by the
addresses.
1.

For I-word COMPUTATIONAL items
CODE:
IN ARGUMENT LIST:
ADDRESS:

For 2-word COMPUTATIONAL items
CODE:
IN ARGUMENT LIST:
ADDRESS:

XWD 100, address
that of the argument itself

11
XWD 440, address
that of the high-order
argument

For COMPUTATIONAL-l items
CODE:
IN ARGUMENT LIST:
ADDRESS:

4
XWD 200, address
that of the argument itself

C-21

word

the

WRITING USER PROGRAMS
4.

For DISPLAY-6 and DISPLAY-7 items
CODE:
IN ARGUMENT LIST:
ADDRESS:
WORDl:
WORD2:

15
XWD 640, address
that of a
2-word descriptor
for
the
argument
a
byte pointer
to
the
identifier or
literal
bit 0 is 1 if the item is numeric
bit 1 is 1 if the item is signed
bit 2 is 1 if the item is a
figurative
constant (including ALL)
bit 3 is 1 if the item is a literal
bits
4 through 11 are
reserved
for
expansion
PICTURE
bit 12 is 1 if the
item has a
with one or more
Ps just before the
decimal point, e.g., 99PPV.
bits 13 through
17 are
the number of
decimal places.
If bit 12 is 1, this
is the number of Ps.
bits 18 through 35 contain the size of
the
item in bytes.

For procedure names
subprograms)

(which cannot be used for calls to

CODE:
IN ARGUMENT LIST:
ADDRESS:

7
XWD 340, address
that of the procedure

The return from a subprogram (via POPJ 17,)
the call.

is to the statement

COBOL

after

C.3.8.2 Calling COBOL-IO Subroutines from FORTRAN-IO Programs - To
call COBOL subroutines use the standard subroutine calling mechanism:
CALL COBOLS (args ... )
X=COBOLS (args ... )

subroutine call
function call

You must have compiled the COBOL subroutine using the COBOL compiler
described in the DECsystem-lO COBOL Programmer's Reference Manual.

C.3.9

LINK-IO Overlay Facilities

LINK-IO provides several routines that are accessible directly from a
FORTRAN-IO program.
These routines are presented here briefly,
together with the FORTRAN-IO specification of their parameters.
In
general,
LINK-IO performs these
functions automatically.
These
routines are available only for your convenience.
Full details of the
use of the overlay facilities can be found in the LINK-IO Reference
Manual.

C-22

WRITING USER PROGRAMS
C.3.9.1 Conventions - The following terms are used
par arne ten, to LINK-IO over lay rout ines.

File spec

describe

the

A literal constant consisting of device:
filename.ext [directory]
A LINK name or number
literal
that
is
a
constant or variable.
A sequence of name
items separated by
commas.

Name
List of link names
The routines available are:
INIOVL

(File spec) Used
to
specify the overlay
file
to
be
found
if
the
load
time
specification is to be overridden.

GETO'lL

(List of link names)
Used
overlay structure in core.

change

the

RUNO'lL

(Name)
Load s
the
spec i f i ed
transfers to that LINK.

LINK

and

REMOVL

(List of link names)
LINKs from core.

specified

LOGO'lL

(File spec) Used to specify where
the
log
file is to be written.
If no arguments are
given, the log file is closed.

For a full
description
Reference
Manual.
-----

these

routines,

Removes the

refer

the

LINK-IO

The
information presented
in Sections C.3.10.1 and
C.3.10.2
is
intended only for
those users who have programs and data files that
were developed using the F40 FORTRAN compiler and
the
FORSE object
time system.
The following sections describe the manner in which both
upward and downward compatibility between the FORTRAN-IO,
FOROTS and
F40, FORSE FORTRAN systems may be achieved.

C.3.10.1
FORTRAN-IO/F40 pata~_~~~_~ompatib~lity - Table C-2 describes
upward compatibility of data
files
(FORSE TO FOROTS).
Table C-3
describes downward compatibility of data files (FOROTS TO FORSE).

C-23

WRITING USER PROGRAMS
Table C-2
Upward Compatibility {FORSE TO FOROTS)

FORSE
File Type

May Be
read By
FOROTS

In The Following
Manner:
--

1. Sequential ASCII

Yes

May be read directly;
positioning
record
e. g. ,
operations,
BACKSPACE, SKIP RECORD,
may be used.

2. Sequential Binary

Yes

May be read directly in
a forward fashion only;
positioning
record
not
operations
are
permitted.

3. Sequential Mixed files

Yes

May be read directly in
a forward fashion only;
positioning
record
operations
not
permitted.

4. Random Access ASCII Files

NO}

5. Random Access Binary Files

NOTE: We suggest that
a random access file
(using FORSE)
be read
and be rewritten as a
sequential file
that
accepted by
can
be
FOROTS.

C-24

WRITING USER PROGRAMS
C.3.10.2 Converting FOROTS Data Files to FORSE-Acceptable Form - The
following paragraphs describe procedures that may be used to convert
FOROTS sequential mixed, random access ASCII, and random access binary
data files into a form that can be read by FORSE.
Conversion of FOROTS Sequential Mixed Files - We suggest the following
procedure to convert a
FOROTS sequential mixed file into either a
sequential ASCII or sequential binary file acceptable to FORSE.
1.

Prepare and run a FORTRAN-IO I/O program that will produce
either a sequential ASCII or a sequenial binary output file.

If a
sequential
ASCII
file
is produced,
it
must
be
line-blocked before
it can be read by FORSE.
Line-blocking
is accomplished by copyirtg the file using either
the
system
COpy command
(with an A switch) or PIP.
The copy will be
line blocked and will be acceptable to FORSE.
The
following
is an example of the command sequence needed to line-block
the data file FOROT.DAT:
.COPY FOROT.DAT=FOROT.DATA/A

IE a
sequential binary file
is produced,
it must
be
record-blocked
before
it
can
be
read
by
FORSE.
Record-blocking is accomplished using the /K feature
of
the
program BAKWDS.
The following is an example of the command
seq~ence needed to record-block the data file FOROT.DAT:
.R BAKWDS
*FOROT.DAT=FOROT.DAT/K

C-25

WRITING USER PROGRAMS
Table C-3
Downward Compatibility (FOROTS TO FORSE)
---·----------------T--------.----------------

FOROTS
File Type

May Be
Read By
FORSE

In The Followin9
Manner:

--_._------------_._-------------jl----------------

1. Sequential ASCII File

Yes

This
operation
is
permitted
if the file is
line-blocked.
This may
be accomplished by making
a copy of the file
using
either
the system copy
command
(with
an
A
s wi tc h )
0 r
the
PI P
program.
The resulting
copy
will
be
line-blocked.
An example of the command
sequence needed
to line
block a
FOROTS
file,
using PIP, follows:
.R PIP
*FOROTS.DAT=FOROTS.DAT/A

2. Sequential Binary File

Yes

This
operation
is
permitted
if the file is
record-blocked.
This
type
of
blocking
is
accomplished by using the
/K option of the program
BAKWDS.
The following is
an example of a command
sequence
which
record-blocks a file .
. R BAKWDS
*FORSE.DAT=FOROTS.DAT/K

3. Sequential Mixed File

(See Section C.3.10.2 for
suggested
conversion
procedure.)

4. Random Access ASCII File

(See Section C.3.10.2 for
suggested
conversion
procedure.)

5. Random Access Binary File

(See Section C.3.10.2 for
suggested
conversion
procedure.)

C-26

WRITING USER PROGRAMS
Conversion of FOROTS Random Access ASCII
Files - We suggest
the
following
procedure to convert a FOROTS random access ASCII file into
a form acceptable to FORSE.
1.

Prepare and run a FORTRAN-IO I/O program that will
create a
sequential ASCII file consisting of the records of the random
access file.

Line-block the sequential ASCII file using either the
system
COpy command
(with an A switch) or the PIP program.
The
following is an example of the COpy command:
.COpy LNBLK.DAT=SEQFL.DAT/A
The foregoing
command would produce a
line-blocked
(LNBLK.DAT) of the sequential file SEQFL.DAT.

copy

Prepare and run an F40 I/O program that will
read
the
file
produced
In step
2 and will
rewrite the file as a FORSE
generated random access file.

Conversion of FOROTS Random Access Binary Files - We
suggest
the
following procedure to convert a FOROTS random access binary file into
a form acceptable to FORSE.
1.

Prepare and run a FORTRAN-IO I/O program that will
create a
sequential binary file
consisting of the
records of the
random access file.

Record-block the sequential file.
This
is accomplished by
using
the /K feature of the program BAKWDS.
The following
example illustrates the command sequence required to convert
the file FOROTS.DAT into the record-blocked file FORBLK.DAT .
. R BAKWDS
*FORBLK.DAT=FOROTS.DAT/K

An F40 I/O program may then be written to convert
the
sequential
record-blocked file into a FORSE generated random
access file.

C.3.10.3 General Restrictions - Observe
the
following
restriction
during the-preparation of FORTRAN-IO programs and data files:
CHAIN functions (as implemented for the
F40 compiler)
are not
implemented in FORTRAN-IO.
An overlay capability that is greatly
superior to CHAIN is available with LINK-IO version 2.

C-27

APPENDIX D
FOROTS

This appendix describes the facilities that FOROTS provides for
the
FORTRAN user.
FOROTS implements all standard FORTRAN I/O operations
as set forth in the "American National Standard FORTRAN, ANSI
X3.9-1966."
In addition it provides the user with capabilities and
programming features beyond those defined in the ANSI standard.
The primary function of FOROTS ~s to act as a direct interface between
user object programs and thi DECsystem-lO monitor during input and
output operations. Other capabilities include:

,..

D.I

Job initialization

Channel and core management

Error handling and reporting

File management

Formatting of data

Mathematical library

User library (non-mathematical)

Specialized applications packages

Overlay facilities

10.

F40 compatibility

HARDWARE AND SOFTWARE REQUIREMENTS

You can run FOROTS on a DECsystem-lO KAlO, KIlO, or KLIO processor.
FOROTS may interface with all DECsystem-lO peripheral devices.
In
addition to monitor or user program requirements, a minimum of 14
pagres of user core is needed to run FOROTS.

D-l

FOROTS
The software required with FOROTS is the 5.06 monitor or a later
version.
Other software items that can be associated with FOROTS
include:

D.2

The MACRO-IO assembler

(version 47 or later)

The LINK-IO loader

The system program COMPIL (version 22 or later) and

The FORTRAN-IO compiler

(version lA or later)

(version 1 or later)

FEATURES OF FOROTS

The following list briefly describes many specific features;
more
detailed information concerning the implementation of these features
is given later in this appendix.
1.

Your program may run in either batch or timesharing mode
without requiring a program change. All differences between
batch mode and timesharing mode operations are resolved by
FOROTS.

Your programs may access both
devices in the same manner.

FOROTS helps provide complete data file compatibility between
all DECsystem-lO devices.

FOROTS does not require line-blocking
(a requirement that
each output buffer must contain only an integral number of
lines).

Up to 15 data files
number or all of
randomly.

FOROTS treats devices located at remote stations similarly to
local devices.

Programs written for magnetic tape operations will run
correctly on disk under FOROTS supervision. FOROTS simulates
the commands needed for magnetic tape operations.

You may change or specify object program device and
specifications via a FOROTS interactive dialogue mode.

Non-FORTRAN binary data files may be read in
FOROTS.

may
the

directory

and

non-directory

be accessed simultaneously.
Any
open data files may be accessed

image

mode

file
by

10.

FOROTS provides interactive
processing routines. These
execution of the program
routines whenever designated

11.

An error traceback facility for
fatal errors provides a
history of all subprogram calls made back to the main program
at the address of the point where the error occurred.

D-2

program/operating system error
routines permit you to route the
to specific error
processing
types of errors are detected.

FOROTS
12.

FOROTS provides a
trap handling
system for
arithmetic
functions, including default values and error reports.

13.

You may mix ASCII and binary records in the
same file,
and
both may be accessed in either sequential or random access
mode.

14.

FOROTS permits your program to switch from READ to WRITE
the same I/O device without loss of data or buffering.

15.

the
FORTRAN-IO
Although primarily designed
for
use with
compiler,
you may also
use
FOROTS as an independent I/O
and
system, as an I/O system for MACRO-IO object programs,
for FORTRAN-IO and F40 object programs.

D.3

ERROR PROCESSING

Whenever a run-time error is detected,
the
FOROTS error processing
system takes control of program execution.
This system determines the
class of the error and either outputs an appropriate message at
the
controlling terminal or
branches the program to a predesignated
processing routine.

D.4

INPUT/OUTPUT FACILITIES

FOROTS uses monitor-buffered I/O during all modes of access except
DUMP mode.
Display devices are supported in dump mode;
formatted
text is handled in ASCII line mode;
unformatted files are accessed as
FORTRAN binary files.
(Refer to DECsystem-IO Monitor Calls Manual.)
The following paragraphs describe I/O data channel and access modes.

D.4.1

Input/Output Channels Used Internally by FOROTS

Fifteen software channels
(1
through
15)
are available
in
I/O
operations.
Software channel 0 is reserved for the following system
functions:
1.

The printing of error messages, and

The
loading
operations)

Software
transfer
table is
channel
assigned
FOROTS.

and

initialization

FOROTS

(GETSEG

UUO

channels 1 through 15 are available
for
user
program data
operations.
When a
request is made for a data channel, a
scanned until a
free
channel
is
found.
The
first
free
is assigned to the requesting program;
on completion of the
transfer, control of the software channel
is returned
to

D-3

FOROTS
0.4.2

File Access Modes

Data may be transferred between processor storage
devices in two major modes - sequential and random.

and

peripheral

0.4.2.1 Sequenti_~L_1..£~nsfer."J:!9de - In
sequential
data
transfer
operations, the records involved are transferred in the same order as
they appear in the source file.
Each I/O statement executed in this
mode transfers the record immediately following the last record
transferred from the accessed source file.
A special version of the
sequential mode
(referred to as APPEND)
is available for output
(write) operations. The special APPEND mode permits you to \¥rite a
record immediately after the last logical record of the accessed file.
During the APPEND operation, the records already in the accessed file
remain unchanged; the only function performed is the appending of the
transfY2red records to the end of the file.
You must specify transfer modes (other than SEQINOUT) by setting the
ACCESS option of a FORTRAN-IO OPEN statement to one of several
possible arguments.
For the sequential mode, the arguments are
ACCESS='SEQIN' (sequential read-only mode)
ACCESS='SEQOUT' (sequential write-only mode)
ACCESS='SEQINOUT' (sequential read followed by a sequential
writ.e)
ACCESS='APPEND' (sequential Append mode)

D.4.2.2 Random Access Mode - This transfer mode permits records to be
accessed and transferred from a source file in any desired order.
Random access transfers must be made between J[ocessor core and a
de vic e
(dis k ) t hat per mit s ran do mad d res sin g 0 t" r:" a t ion s to f i I est hat
have been set up for random access.
Files f;:
random access must
contain a specified number of identically si~~d records that may be
individually accessed by a record number.
You may accomplish random access transfers in either a read/write mode
or a special read-only mode.
You must srecify random transfer modes
by setting the ACCESS option of an OPEN stdc2ment to one of several
possible arguments.
ACCESS= 'RANDOM , (random read/write iii,ide)
ACCESS='RANDIN' (random special read-only mode)

D.S

ACCEPTABLE TYPES OF DATA FILES AND THEIR FORMATS

The following paragraphs describe the types of
acceptable to FOROTS.

D.S.I

data

files

that

are

ASCII Data Files

Each record within an ASCII data file consists of a set of contiguous
7-bit characters. A vertical paper-motion character, such as, a Form
Feed, a Vertical Tab, or a Line Feed, terminates each set. All ASCII
records start on a word boundary; the last word in a record is padded
with nulls, if necessary, to ensure that the record also ends on a
word boundary.
Logical records may be split across physical blocks.
There is no implied maximum length for logical records.
D-4

FOROTS

NOTE
On sequential
input,
FOROTS does
not
require conformation to word boundaries;
it reads what it sees.
Therefore,
any
file
that
is written by FOROTS will
conform
to
the
foregoing
format
requirements.

D.S.2

FORTRAN Binary Data Files
--- - ----.- .--..
.

~--

Each logical record in a FORTRAN binary data file contains data
that
the executing program llIay reference with either
a READ or ~\1RITE
statement.
A logical record is preceded by a
control word
and may
have one or more control words embedded within it.
In FORTRAN binary
data files, there is no
relationship between logical
records
and
physical device
block sizes.
There is no implied maximum length for
logical records.

D.S.2.1 Format of Binary Files - A FOROTS binary file
may contain
three fornls of Loglcal--Segment Control Words (LSCW).
These LSCWs give
FOROTS thE' ability to distinguish ASCII files from binary files.
"

LSCW
001+ the number of words in the segment
(exclusive of
any "END" LSCWs)
002
indicates
that
the
segment of a disk
block
boundary continues
003+ number of words in the preceding segment including
LSCWs.

START
CONTINUE
END

If the access you specify for
a
file
(through
the OPEN statement
ACCESS
par ameter)
is
'SEQIN', 'SEQOUT', or 'SEQINOUT', all three
LSCWs may appear in a record.
If the access you specify is
'RANDIN',
or
'RANDOM',
all
records are of the same length, and there are no
CONTINUE I,SCWs.
The following examples illustrate the LSCW.
file contains only 001 and 003 LSCWs.

c
c

~OOK

AT A BINARV

rl~E

AND SEE THE

The random access
LO~ICA~

CONTROL WORDS.
OP£N(UNIT=1,ACCESS='RANDOM',MOD£~j8INA~V',

RECORDcl~~)

1-5

WRIT£(1'1) (I,

J=l.1~~)

J=:'
~RITE(1'2)

(J,K=1,10~)

END

D-S

SEGMENT

binary

FOROTS

"";' 0 Ql ~
2I07k'J01
2102002
~et: 211213
021/004
0022105
00;:'006
"e{,0~7
12l0:~el"

00J011
00?012
2101013
210.~ 014

210102121 21 0" 14 5 - Number of words
21212121021 00"005 in record counting
00002121 0021005 END LSCW or the
number of words
0"00~21 121"012105
following this
2102HZla0 ~2100"5 word to the
002'0210 0~0~05 END LSCW.
2'00000 0~00"5
;:'0""~00 000005
0~HH?l00
~000012l

~"0005

0Z0~05

~12l2l;:'00

121"~005

00,~015
12J~F'2116
~0:017

Z0,,02!12I 121000215
0 121 121005
012100QlI2I 0eJ2I005
el0e1elQl0 ~t"I0005

00,' 020

00~el12l0

0e,~021

0121~0021

0~121005
~el"005

0ft"~022

0021000
121210000 0121001215

l2I~h'e23

01210!21~0

00;'024

etl2l00Z0 00rtJ005
~1210~00 a0121el05

12J'L~025

00/026
00,: 1212 7
1210.'21321
121 0/031
1210:."032
1210712133
1210/034
121121;:12135
001.'12136
00~037

00,;1214121
00?2141
001042
1210:043
210 ij 121 44
1ll0?045
00 ;·~eJ46
00~047

00;'215"
00,;;12151
1lI0~~ 2152
00 ~.\ 0 53
00,'054
1ll2l?055
00/056
QlIlL' 057
00MZ!60
00:-'061

210~HJ00

~000215

~"0"021

~0"005

2101063

~kH'~~12I

000005

00lH'71
12l0~'072

"02073
1lI1lI~0'04
"0~"75

I2JI2IL~117

(2)0 ~,1221
12121~121
00~~122

000123
000124
1210C125
000126
~0"127

000130
000131
0""~lJ2

0021133
0001304
12J0C135
"00136
00~lJ1
00~140

00e141

~"'0005
e~0"05

~0~0~0
00~0{JIC'J

00.'~07"

1210~11~

0~121012!5

12J0,~062

00:,~e.67

1210f.116

00e!02J0 012l0e105
~121"02!121

00002121 21000215

~12l0~05

00 12! 12121121 ;;'001211215
01210121021 ~~2101215
~~HHH~12I 21000215
00(211210121 ~0001215
~H"~Z 2' 21 ~el012105
121211211211210 r2l1210005
2121021210 121"001215
12121 QlI2I eJ2I 0 0 00215
121121012100 0121~e1215
12112I~0Z'IC'J ""001215
~000;:'~ 0"'00"5
00i2!~~121 0"121005
0000021 121"'02105
0001210121 00001215
01210000 01210005
00001210 00012105
el2l00~21 0""205
0021021121 2100005
"flJ00 21121 0"'012105
21",,000 121~~0215
0IC'J00~0 0"00215
~12I00a0 01Zl2l1(l05
~02!Vl0121

021"'r2!~21

00;~~65
00~j066

210.12176
12J0 ..~21 77
00 ..' 100
001101
00/11212
00711213
00111214
00711215
00 106
00:'107
00;/110
00C'111
001112
e10i-:113
1210l~ 114

0000210 0210005

a"0005

00~~021
~00ftH'l21

~"0~05
~021~215

0000210 21(1121005
00~IiH'" 21"'0005
00~"00 000005
000000 012'J0005
~rtJ0""0 0"0005
"000Z0 0210005
0/cHHHl0 0P.102l05
012l00~0
0210"~21

;'000215

~12112!"0121
~0~21"'21

~0001215
~~~005

(1002)"'121

~"12Ie105

;:'0~0121121
~0121000

0121121005
32102105

0212102121

~e!0"05
~~00215

0121e1~121121

21~00215

0000210 21~00215
001212100 0"021215
"0,,0Ql0 0 0 210215
0000~21 002121215
121000021 ~012101215
121000"0 12I~0005
~0121""'0 000"'05
12112100121121 ~00005
"0121121(2)121 ~00005
~12100021 0"'012105
12112112121021 ~12l0121215
00121211210 2000IC'J5
0000Ql0 0~"~05
QlflJ2I0QJ2I 0 0 210215
I2IflJl " 01lJ "2l QHH' 5
"11"et21 121""0005
21"2'''1210 121 III "121 '" 5
2121000121 ""'021215
0"121~1210 a"000!'
12J00~00 21002'05
001210121121 0210"~5
00k"0021 121000215
0012112100 000"~5
02100021 00~21~5
2J00000 0"0"05
0001210121 ~0210"5

00'~142

01210~0121

0"'0~05

001.143
00'~ 14 4
00l~ 14 5
00;-146
00/147

210210210
0000121121
12103000
121211000
000""21
1210121121('10

000005
0001<46 -END LSCW
121021145 Containing the
of words
0 12l 0"'07 innumber
th(~ reeord

00~~150

D-6

~"'012J"5

00~2164

~~00~5

;!J~"007

including LSCW's.

FOROTS

00('151
00J152
00/,153
00J.154
00."155
00.~ 156
00,'157
00:l160
1ZJ0/161
00l'162
00~163

00J164
001165
00;~166

00,a67
00;~ 170
"'0~' 171
00 ~'172
00/;173
00,'174
00~1175
00,~176
00,~ 17 7

'-""el0il0
~0"'''~0

1ZJ0eJ000

0"21C.H~7
0Q121~07

000007
eJ00000 Zf'IZJ007
00'-"0210 ~02J2!07
000000 ~000"7
0~H~000 0"00,,7
0"~0~PJ 00210217
00121000 ~~0~"7
00(210:110 ~00~HP
0000021 ~e!0007
~"0000 2100('107
000""" rlj0QH'J07
0000210 ~H~0007
00e1~""

0000~IZJ
2lIZJ~e1k'2

el0IZJ~07

k""0~17!0
~IZJe'''0IZJ
il"0~~0
0"00~21

0~IZJ0"7
2!~IZJzj27

Z~"0IZJ7

2ItoHl!007
""00210 2 0 2007
"00000 0"0007

00.~203

"'0k'J"~0 0~IZJ0IZJ1

1210~~221

1210J222
0"~:223

I2)2IJ2204
0"~225

12100226
00 ~1227
00~~2321

00~'231
00:~232

2!0et0~0

000~'HJ
00~0~0

001,242

0021000 ~00(2107
IZJIZJ0000 0 0 1ZJ007
2l000e1IZJ 000007
"012'000 0021007
"'021"'00 ~(2I0007

00~'265

0rz/266
00;' 2 6 7
00;'270
00/271
00,J272

2"0~07

00eJ02!0 ~00007
0012'00'21 0"'0~07
2l0"et?J0 0021007
00,,000 ~~kHH1j7
00002121 0"'00~7
00et0~"lJ

00~~240
QJ 0 k~ 241

00 r"245
00/246
0,,1/247
00!.250
00J251
002252
e!0"253
t?J0J254
e10?255
00:'256
00/257
00.1260
002261
00~' 262
00 r~ 263
00/264

J"IIHHP

2!0~QltJ0

00.J235
000236
00e237

21000217
0001ZJ2J7
0012HHH
o
" 21 " '''' 002100'
000flJ~0
0IZJ0et00 ~"Ql007

00~243
00~~244

0eJ0007
~"000IZJ 000007
002'0021 02'0007

00,; 200
00:201
00:202
00."204
00..'2r215
00/206
00:207
00,1210
0"".i 211
00,'212
1210._:213
1210?214
"" ,:215
0(,h'216
"0:i, 21 7
1210>"22121

00,~233
00~234

0"21007

(1~0~"7

"021021" ~~IZJ0rl17
121"1210210 2l00r2!07
~:HH'01210 000121217
1210001210 2lfll2J007
r2!00000 ~00007
121000021 ~(2!00IZJ7
"2102100 ~02100'
21~HUJ"" 12102100'
00 ~0 Q"~ 21 0 2100'
0(12)01210 21002107
"00000 012100'"
00001210 0"0"0'
1212121000 """00'
1210121000 000"07
212112101210 ,,02112107
0001210" 0"00217

0~H~000

2!"et"0"
2!00~2!0

~0eJ000

00e'000
~00000

0~l275

~0~fZl021

1210~302

00};31213
00JJ304
00;~305

00031216
0013307
00~310

"00311

00~312
00~) 313

0~0007
0~0007
~e!"r2J07

eJe!0000 0"0007
~"'HH"0IZJ

"0~277

0~00"7

0Q10r?107
2100000 i(j('J0"07
0~H~"02 002()}2I'
00002'0 ~2!0etIZJ7
el0t302J0 00021~7
0IZJet0~0 2100007
0""000 0r?10~07
"00~00 0 2J "k"1217
~0et000 0""CJ:I07
21"0007
2! 0 " ~ '''~
~2"""0 0"'0007
~rU'''210 000001
0" ~"2J" 7
0000021 ~~I?HHJ'
~"00~0 QJ'!l1ZJ007

1210f274

00 ..j30121
1210(;301

~00007

21000217

~00~eJ"

0~;"273

1210.1276

D-7

~IZJ~"2f2J

~0rlJ""IZJ

~00007
~0IZJ(2JIZJ'

2100eJ07
"002100 00IZJ2'~7
00212'00 12112100217
"021000 0"02107
0"210~0

~0"Q!07

eJ000"21 121002107
2121121121""" "~012107
0121'H~"0 000"07
01211211211210 2100121121'
210121021121 12121012107
1210,,0"0 ~r;001.'J'
121012100" 01210007
12100"1210 000"217
12100211210 000"07
21030210 000146

FOROTS
In the sequential access binary file, the second record crosses
l28-word disk boundary and contains a 002 (CONTINUE) LSCW.
~OOK

C
C

AT A BINARY rl~E AND SEE THE ~O$tCA~ SE~MENT
WORDS.

CONTRO~

OPENCUNI TE 1,MOOEc 1 BINARY')
la,

WRITE(1) (I.

j=1,1~0)

J.,
WRITE(1) (J,K=1,100)
END

00,~0~0

~~10~121

00J001
1Z10,~ 002
1210 ,~1ZI1213
00:1211214
1210.:005
1210.~ 0 0 6
1210,'007
12J12J. f{l10

~0r2'''00

12112J~el11

1210,'12112
o 0.~ 0 13
121121/12114
0121.'12115
IZI~ ,';016

~00~2JIZI
2J0~000

0"0"el5
0012100121 210"005
~12I2!~"0

~0eJ0i30
00~0~12I
ellZlll~alZl
~12J2'Cl2!0
~I2JPJ02J0
~12J2J~~I2J
~IC.H~rl2JI2I

000~05
~~00e15
0~02!05
2!~02J12I5

ij~0~~5

0~ ~017
1ZI~1'020

00,"12121
0~h'022

012J~1ZI24
0~"025

00/026
00.'027
00 •.'030
00L~031
1Z10~032

1210.3033

2l"121~05

lJ "121 CH'l 5
12100005
0012101215

",0121005
000005

~02!~00

0"'0~05

el1Zl002Jr2I

~012101215
0~rzl012J5

~~.''1l61Z1
~1ZI/e;61

2J~~~el~

~0:,062

0"l2Il2Jrll5

1ZI~~063

2100~~0

21iiHl! rll ~ 0

~~12I12J05

210~0~1ZI
~1ZI~0~0
2J~~02J0
0~HH'\?'!0
12J00e1~121

0~00"5

210'064
00.1065
21121:'066
121121/067

eJV"02J05
;3e!1ZI005
021l2lel05
210121005
2l00"~" 121"001215
00121rll~0

"~0005
~"12I005

000000
00000121 0ff'0005
00212100 0~"005

00l~034

~01Z1"'00

0~012J2l5

002101210

~2!"2105

0~H!01Z10

0002'05

eJl2I~IZ!2!"

~e!"21215
~00~05
12100~05

00e1~210
~12100~0

D-8

~IZI(l1~eJ0

~~rzlv.H'l5
~~0~05

012J;;07~

000it'V'JIZI ;300"'05
I2JIZI~0~0 ij012112J"5
01Z1~012J0 2J 0 0"0S
001?102JIZI 2lr,12I005
012100l?!0 0~0e!"5

12107011

002lZJ~0

0~12I0"5

012J~"072

0121::'Jrll~"

000~05

1210?1ZI73
210/074
"0;~ 0 7 5
0121:-'076
12121 {~0 7 7
1210;'130
0121 CO' 101
00.:102

000"0121 00rc"3~5
0021000 o ff''' r21'"

00K'J~~0

00eJ"~1ZI

0~00"9
~"1000S

I2J 02' " 0121 0C'J0"05
2102'0121121 2l~~HH'5

012J;~ 1 "'4

eJ0'-"eI~0
2l0r.0~121

~00~05
"~~HH"5
2l"0~1215
i'~0005

00.)105

"r3e21~121

{JeJ0eJ12I5

00~103

01210000 0"012105

~012112105

2002'00 0 0 0"05

0'-"0~05
~~0~05

IZIQh3 121 35
0121 (H'J6
00?037
0121 •. 1214121
00 ,'~ 121 41
lZIep 121 42
1

~0000121

12101210210
1210012100
001210121121
'''HH'l01Z1
00211210121
0000<Jr2I

1Z10,~052

000~05

12I~12I0"5

1210~050

I2Il2JJl053
00/12154
121121.-055
00.'056
121121.;057

"r001215
","0'-"05

el0~~00

2J0 121121 21 0 ~(2j0~05
2)00021121 ~~0005
1I02!12I00 1210121005

1210L~047

1210/.051

2!r2'012J12I5

002!~~0
00e10~0
0000~1ZI
~rzle0~0

0121 ·::023

00 043
1210 044
121121 045
1210.;.~ 121 4 6

~~0145
00121~05
~et0005

?I1ZI0~211Z1
~0~02!121

the

FOROTS

21 0 01211215

~0Z173

~00005
000~05

00;'174
0"(175

00~: 1" 6
0el107

~002'0121
01210~0121

00~a10

0121000121
01210""121 0 0 01211215
~0121~121121 0 0 1211211215
~210r;,H'0 12102101215
0211211211210 00001215
121210012121 00211211215
00012100 1210001215

00;'1111
00i-'112
00~113

1210.:1114
00~115

000116
003117
1210C~12121

00 ;:~ 121
00~122

1210?123
00 ..'124
l?Je~125
00~'126

00~176

021 ~~ 17 7
00 •.1200
o 0 ~~ 2 e 1

~121121""121 12I'''H~05

0121"00121 ~0121"1215
0121021121121 00tlJl2I1215
121210121121121 000~"5
0121012121" 212101211215
01210~0"

~012101215

00.~147
0e~'150

00210""

000131
000132
"r.:H~133

000134
000135
"'Ha36
000137
00 \I~ 14 0
00r141
00e142
003143
00~~144

00~'145

000151
00~~ 152
001153
2I0'~ 15 ..
"0 ,'i 155
0ih?156
00~157

00/160
0211'161
:021;1162
l{Je'~ 163
11'10;:164

"0~00121
000~1tJ12I

000000
00r2'~00

"~0007
00121~"7
~0"007
0~1?J"'12!7

00e223
00~~224

0002225
"210226
eJe~227

l?Je?230
"0e231
0212232
"e~'.233

words to
next LSCW.

"21;;234
002235
001236

021;;237
00t~240

0217241
0ei242
2101'243
0212244
0~h~ 2 45

"021000
2100021121 (')0121007
()J12I002J0 0r.0007
012100210 00121007
000~2J0 210001217
V'~0007

0000~~

~0121007

~"0007

1~0l166

01210000
000000
0000:;'121

i~"H'16 7

eJ12I0~00

I~" (~170

000O""

12'0 .;~ 171
1l'0.J172

0e?214
121217215
00t-216
002217
00"2211
0212221
02170222

21~01211217
~~0007
~00007

0"et0~0

1~01165

00~212
0~h"213

II""'"

~0121"00

00~00121

0r21e1000

C'JI2I"0~21

00012100
012101210121
021000121
012100121121
0'HH'I00
000021121
01210210121

1210,~ 206
00w"207
"21:210
2107-211

00V'146

llJe0127
"0Qi132J

00v.~202

0el."21?l3
0eJ204
0e(~212!5

121''''021'' 21"012105
12110210121 21000215
21""01215
rlIQUI II 0e 0"00215
121012)121"" 12100"05
0""00" 121"""1215
002121121" 21"'02105
~"12I021" 0""""5
121121210"", 1(J00"05
121121210021 """"'rlI5
~121"0~" ""2101215
210 121 Z0121 0"""1215
2102121"0 21"0"05
"01210"0 0"0005
2)000"", eH" 0 0 '" 5
"0121"021 ~~"2I05
""3000 ~~12I146
001021121 21""'12132 -Number of

00,~246

00''';247
00/250
0212251
0e~; 252
2J0.~ 253
021/254
2121 255
00 256
00 257

~00007

eJ~12I2J"7
~0"02l1
"~0007
~~"'01217
~0"01217

D-9

0000021 ~"0007
01212100121 0"1Cl007
01210021121 ~"0007
0000~0 ZlQll2l007
00001210 121000217
002~021 i2l '" 0114 --Continue LSCW.
021012100 ~01210"7
~"0"~P

02'012J07
0~121007

210001217
0 0 12101217
"eJI2I~07

121"12112107
~012112107

el0~IiH~12I

21 "'rlI2I07
~0""00 21002107
Vl012HlI ~" 2IftJ0eJIZl7
"'0et00121 2IeJ0~"7
0"21021121 ~01210e'7
210210"0 ""2121217
121121121021121 "~"012!7

""0~2'0
"lel2l~12I

010"""
"012100121
0"0~0"

000"210
0021021121
~00000

"I(J""~"
012121000
000000
00210210
002100"
2102020
"1210000

,,0rl1"~1

21 ill "'''1217
,,01210211
21 0 0007
""0"0'
210"""7
""0"'07
0"001217
0"''''''1217
2I~"007

210121"'07
Z001tJ01
000121217
0r2l0007
0"02107

eJ0ZJ000 0e10001
01212100121 ~"''' 0 e' 0 7

000000 0eJ0007
01211l0"0 000007
0"r2'000 0'-"0012!1
00212100 0~"HJl07
~"H"Z:0121 21"121007
002100121 0"0007
0000"'0 2100007
ZlI2l0~0121

0"'0~07

2)00;'00 12!(10e107
0000t(!0 ~"0007
00etk"el0 21eJ0'-'l07
000000 12!k'l0eJ07
eJ0""00 0:l11C!1007
((J'H~01210 12I('ll2lel07

FOROTS
0~0007

00,~2621

V'J00000

"0~~261
eI'H~ 262

~0""00 0~0"'IZI'

002263
1210L3264
1210(')265
00~~266
1210<~267
00;~ 270
002271
00i272

00i~273
00~"274

00.3275
00v:~2' 6

"0l277
00~300

00""00 00000'
"'00030 0"''''07
"0012100 0210"07
12100"00 ""'0007
001210"0 1211210007
1210,,000 0 0 0007
"0,,000 0"0007
12100000 000007
"000"0 000121211
"0121000 ~001210'
12100"1210 000007
"000"21 000"121'
"00121,,,, 0210"'0'

00e301
00;'302
00e3~3
1210~3"4

V'J0031215
00J31216
002131211
1210t310
00~311

12100312
001313
00l31.

Image mode files contain no LSCWs.

C
C

2!01lJ001
000000 000007
210121000 00012107
001210121" 00012107
00001210 a~0121"'7
"2112101210 01ll0"'"
0012100121 00012107
"000021 01210"07
"012101210 0"0"217
"0121000 000007
001210210 0210021'
12100000 000"217
"0012100 121021"'"
0e30"0 121"21147

00~0121"

You cannot backspace this file.

AT AN IMAGE MODE rl~E AND SEE NO ~OGICA~ SEGMENT
CONTROL WORDS.

~OOK

OPENCUNI TE 1,MODE·'IMAGE' )
1-5
~RITE(l)

(I, J=1,100)

J="7
~R!'TE(1)

(J,K=1,100)

END

1210 . ~ 000
0021001

0000~21

1210~002

"21210021

"eJ2I~215
1210~005
00kH~05

0000213

00~C!!"'0

00Y'00~

~"0""05

0012!0021 21021005
000000 0"21005

"0 i:~ 0 5

210,,012121

21~21000
21~~000

~~00215

00~013

k'!00"05
00,,0"0 0 121 0005
12l0~H'00 (1000215
e!000"'21 0021~05
e'210000 ~021005

000014

~000et0

~02100r;

00~~015

01210000

~000"5

00'12116
0021017
00J020

0000~0

0°"005

0~P0216

00·~"~7
00.~2110
00C~011

00{j012

00;~021

00lel22

21021023

0000021

0 el 0"05

~021"Zl2I

0rl'21005
0!I'J0005

0210~210

001026
210~027
00~0321

21 002131
000032
"0012133
00('1034
"0Z0J5
00J036
00~0J7

k'l00040
O00041
00"'12142
00J043
00r.l044
210 ~~ 0 4 5

~021005

00"0~"

~0 00 ~"!'

210J024
00~025

~"'21~"-I5

00~~46

0210041

D-IO

~00000
0000~0

rc.10000'
J0e"05
rzl0"0~H' 00(l!005
00"0021 ~('I2I0215
"'0012100 0"0005
"00000 2102112105
0000215
~
II'
210"00" 12100"05
00""0"0 ~~0005
00"000 000005
"00000 ~eJ0005
~00"~0 " " ~H"!' 5
0"0000 000"05
"00"~21 000"05
~"00210 000005
000000 0210"215
00012100 0210121215

' '!J' "

021~0"~

"21000e1
"21210~0

~~0~215
~eJ0e1e15
~0rlJ005

FOROTS

00..1050
00210'1
00~052

00;'053
002!054
0rlP055
00J056
002'057
00~060

"0"061
002062

"000"0 0(l000!5
k'J0~"0k'J 000005
"""01ll0 ~0QJeJ0!5
00eJI2I0eJ 0 0 0005
"0"0"0 ,,00005

000135
000136
0rZW13?
"001421
000141

"21,,0"0 000"05

001143
0el144
2100145
00·~ 146
001147

0000~0

02102100 0021"215

et"00~0
et0C!1"0~

00~~064

2'00e''''0

0r21/~72

"21·~07J

00 'I~" 7 4

00~075
00·~0'6

00}r2177
00.,110121
0e~'101

0(£P102
210 ~~ 103
"121;)104
00.~ 105
0e~1"6

00J1r2l'
0012110
0212111
01212112
001113
00k~114

00~115
01Z1~11116

1210J11.,
"e~120

1210;]121
0eJ122
1210~123
"0~12~

00;112,
000126
2102'12'
e12!~130

0rtH::131
00~132

"0?133
0121~134

~~00""

"""0~0 el f2I 0"05

00;~063

0'H065
00,1066
0ICH'''6?
00;''''''
00tlll71

00~142

?J0~"'00 ~"0eJ05

~00""21
021~~00

000~~0

~'H'J""'0
0~HH'l00

"'''00~0

~"0005

0~2150

a 21" ~"!J!5

IZIIC'Jl;151

~000215

J00005
0"0"'215

"0~152

eJ00005

0e',~155

00~153
l2Ie~154

~r'0005

002156
02!l7.157
00k')160
001161
008162

0~0"05
~"0005

~0~0021

Oet0"'05

eJfZl2!"~fZ1
~"~000

0~0~05

~0'H'05

0e~16J

002101210 21 I2l 21 005
210"0et0 21"21"'215
~0"0~21

0217164
210.3165
0r21l166
021 ~~ 16 7

0210~05

002'0"0 "~"005
02100021 ~0210215
00121"021 0021"05
~0~00"

0e(~170
0121 ,.~ 171

~0210215

'-"00000 01ZJrtHH'5
121210000 0 0 0"05
e121~00" 0210011'5
el0,,1l'''0 el 0 210215
0210000 ~1ZJ2I"05
00,,0210 eJI2I012!05
00"i2!210 ~Ql0"05
~0e1~"0 0°"'''05
iZl00000 ""0"215
000000 el0001215
12!0""021 000005
021"0"0 ~0"0"5
21210000 ;H~"005
21 0 '!H~ 0 0 ~1ZI00"5
0210"~0 0rl!0"05
00121000 {Jk'!21005
!,"BtUI " 0 000005
010000 0°""05
011110 ~el00"5
00"""0 0~0005
00"000 0"'21"05
0021000 "~21"05
"0,,0"0 000005
~00~f2!0 0021"05

~00"''''' ~~01Z1'"

~"2'21~0
000~00

,,12l2l"07
~~21007

021002121 012l00"7
001210etflJ 0002'07
121210000 ~000k'1'
21 'HH~II2l" 0"0(210'
0000~0

~0000'

0'HH!'''0

000~07

I;HH'lel~0

0210(2107

021 I:'! " ~'" 0~"0'"
"2100021 0212100'
~00"w)0 0000217
el2l~2100

2100~0'
~~0007

00.~172

00"~~.H!J

121021'3

0210000 21°"007
000('10rlJ 00rlJ00'

00~1?~
00,,~17'
0r21~~1?6

0000210

01ZJ0':H~7
~1ZI0r?J07

0"?177

~0~eJ~0

eJ~210'"

01Z1.~2e10
00~'201

0"12!0~0

0e10~0?

000'3202
00:~203

001.2(214
00221215
0'h~206
0r21\c~20"

00 ~~ 210
"r21~211

"0;,1212
000213
00l-214

""0215
0e~216

D-l1

"0210021 0"0"05
00210021 ~000"5
000000 ~"0eJ05
021,,000 000005
0~H"!J00 0"'0005
"0~000 0210005
"002100 ~2100"5
"210000 ~0000?
"002100 00"~eJ?
~00000 ",O0O",
"2100021 0 0 0001
rIHH"0~2I 000210?
02101211Z10 0~000'
0211Z11Z11Z10 elrll01Z11217
0000eJ0 0°000'

000~~0

00210"0 21"0007
000000 2100~0'
0000~0 0"'0"07
f2l000~0
2!I2I~0k'!0

~r2l000'

0~000?

0000"0 ~""007
(2I012!eJ00 0 0 012107
(2I01Z12~0 021012107
0000~21 0"0007
00,,0"0 000~0'
00210210 01210001
0000"0 01Z10"""
"00000 "~0001
~00"00 la0000'

002220

""~211

00~(2I0"
~012100"

00~221

rlIIIJ0"'e'0

~00007

tj2l000'
~el00"7

FOROTS

VJ0C222
0QH~223

1lJ0e.224
"0~225

00J226
002221
00::'230
00Z231
00~232

"01233

00~234
00~235
r2!0~~236
01LH~237
r2!~H~ 240

r2!0!241
r2!0},242
00':~243

00<'244
021/245
r2!0)246

0"Qle'H~ ~00~'"

20000fl1 0 0 0"01
000000 12100001
0000~0 ",e"007
000""" 00fl1007
~HH'" 021 00fl1007
~eJ~0eJeJ

(;Ili2l~1263
0QH~,264

0~ {~2 65
00£' 266
00"267
00,) 270
(210:271
0e·:· 2 72
00/273

021 flIei 07

00000fl1 eJ~flIk'l07
0"0""1210 2100007
00eJ"~21 eHll 0007
021~0~21
0eJ00~r2!
~HHHJeJeJ
~000210
~r2lQH"~12J
ell2l~~~2'r2!

el00~217

00fl1el07
0000217

o "r2HHH
1eJ0~07

11002107

2l0"~012l

2t'10007

~0~0~0

~~~Ql01

eJ00Q!00

~01210(2!7

Ql0~0~0

021'251
00 / 252
r2!21?253

~"'1C"~07

e!000QH21 0210007

D. 5.3

~0?261

~"0"00 00fl100'
QI"'HH~~0

Ql0~0~0
el0t'1~00
(l0~~Z'0

255
256
257
260

00?262

~0fl1007

00~247
00,,~250

00~254

00
00
00
00

i21'H'''~0 000007

(101212''-'"

,,00~i217

210210'210 0el00fZl'

~0~eI~eJ 0000k'l7
eJ00~(!1lJ 12l~0021'
~k'l0~00 0~0007
~021el00 0 0 001217
eJk'le!~021 ~"'0007
0"(2I0~21 2Jt'l0elfllY
2l000~flI l2l~flI0fl17
et0'!!02'0 2!~0~0T

21"'~0021

2ll'l2l~07

021 0eJ elflI e!Illfll007
~000e!0 0 0 00217
i2lkHH' 21 0 j{J0001?J7

00'~2'4
00~' 275

0~H"I2l2!12I
eJ000~0

~~1?J007

00/276

Qlk'l~0et0

210~217

eJ0e!etrar21
eJ000Ql0
21000210

~00"07
12l~0~0'
12l"~HI07

00/300
r2!01301
00/302
2121 __' 303
r2!0/304
o 0 ~', 3" 5
00,~ 306
00 :,~ 301

~ eJ~H'I'P
200~"7

e0e1~eH2J

~"Hlele!" ~~212!07

~0r2l"r2l0

210"'2100
00~H'l210
002!~~r21
~12l00el0
012l~H~2!0

200211217

~~0Q1r2l7

21002107
I2I~012!1?J1

0 0 01211211
IZlt'lflll2l1211
0 0 0211217
00001217

Mixed Mode Data Files

FOROTS permits files containing both ASCII and binary data records to
be read.
Mixed files may be accessed in either sequential or random
access mode.
Logical ASCII and binary records have the same format as
described in the preceding paragraphs.
In random access mode, the
record size must be large enough to contain the largest record, either
ASCII or binary.

D-12

FORO'rS
D.S.4

Image Files

The image data transfer mode is a
buffered mode
in which data
is
transferred
in a blocked format consisting of a word count located in
the right half of the first data wurd of the buffer
followed
by the
number
of
36-bit data
words.
The devices that permit image data
transfers and the form in which the data is read or written are:
Device

Data Forms

Card Punch

In image mode, each buffer contains
three
12-bit
bytes.
Each byte corresponds to one card column.
Since there is room for 81 columns in the
buffer
(3
X 27) and there are only 80 columns on a card,
the last word contains only 2 bytes of data;
the
third
byte
is
thrown away.
Image mode causes
exactly one card to be punched
for
each output.
The
CLOSE punches the last partial card and then
punches an EOF card.

Card Reader

All 12 punches in all 80 columns are packed
into
the buffer as 12-bit bytes.
The first 12-bit byte
contains column 1.
The last word of
the
buffer
contains columns 79 and 80 as the left and middle
bytes, respectively.
Cards are not split between
two buffers.

Disk

Data is written on the disk exactly as it appears
in the buffer.
Data consists of 36-bit words.

Mag net ic

~~ape

Data appears on magnetic
tape exactly as
it
appears
in
the
buffer.
No processing or
checksumming of any
kind
is performed by
the
serVIce
routine.
The parity checking of
the
magnetic tape system is sufficient assurance
that
the data
is correct.
All data, both binary and
ASCII, is written with odd parity and at 800 bits
per inch unless changed by the installation.

Paper Tape Punch

Binary words taken
from
the output
buffer
are
split
into six
6-bit bytes and punched with the
eighth hole punched
in each
frame.
No
format
control or
checksumming
is performed by the I/O
routine.
Data punched in this mode is
read back
by the paper tape reader in the same mode.

Paper Tape Reader

Characters not having the eighth hole punched
are
ignored.
Characters are truncated to six bits and
packed six to the word without further processing.
This mode
is
useful
for
reading
binary tapes
having arbitrary blocking format.

Plotter

Six 6-bit characters per word are
transmitted
to
the plotter exactly as they appear in the buffer.

D.6

USING FOROTS

FOROTS has been designed to lend itself for use as an I/O system for
programs written
in languages other than FORTRAN.
Currently, MACRO
programmers may employ FOROTS as a
general
I/O system by writing
D-13

FOROTS
simple MACRO calls that simulate the calls made to FOROTS by a FORTRAN
compiler.
The calls made
to FOROTS are to routines that implement
FORTRAN I/O statements such as READ, WRITE, OPEN, CLOSE, RELEASE, etc.
FOROTS will provide automatic memory allocation, data conversion,
buffering, and device interface operations to the MACRO user.

D.6.1

I/O

FOROTS Entry Points

FOROTS provides the following entry points for
FORTRAN compiler or a non-FORTRAN program:

D.6.2

from

either

Function

Entry Point
ALCHN.
ALCOR.
CLOSE.
DBMS.
DEC.
DECHN.
DECOR.
ENC.
EXIT.
FIN.
FIND.
FORER.
FUNCT.
IN.
IOLST.
MTOP.
NLI.
NLO.
OPEN.
OUT.
RELEA.
RESET.
RTB.
TRACE.
WTB.

calls

Allocate software channels
Allocate dynamic core blocks
Close a file
DBMS interface
DECODE routine
De-allocate software channels
De-allocate dynamic core blocks
ENCODE routine
Terminate program exeuction
Input/Output list termination routine
position to the next record (RANDOM ACCESS)
Error processor
Overlay interface
Formatted input routine
Input/Output list routine
File utility processing routine
NAMELIST input routine
NAMELIST output routine
Open a file
Formatted output routine
Release a device (CLOSE implied)
Job initialization entry
Binary input routine
Trace subroutine calls
Binary output routine

Calling Sequences

You must use the following general form for all calls made to FOROTS:
MOVEI
PUSHJ

l6,ARGBLK
l7,Entry Point
(control is returned here)

where:
1.

ARGBLK is the address of a
specifically formatted
argument
block
that
contains
information needed by FOROTS to
accomplish the desired operation.

Entry Point is an entry point identifier (see list given
in
Paragraph D.6.l)
that
specifies the entry point of the
desired FOROTS routine.

D-14

FORO'!'S
with three exceptions, all returns from FOROTS will be made to the
program instruction immediately following the call (PUSHJ 17, entry
point instruction). The exceptions are:
1.

An error return to a specified statement number,
or WRITE statement ERR=option,

An end-of-file return to a statement number,
WRITE statement END=option,

i.e.,

READ

A fatal error that returns to
package.

the

monitor

i.e.,

READ
or

debug

Paragraphs D.6.3.1 through D.6.3.11 give the MACRO calls and required
argument block formats needed to initialize FOROTS and FOROTS I/O
operations.
Argument blocks conform to the subprogram calling convention described
in Appendix C.
However, there is one exception in dealing with the
first word of an I/O initialization call, i.e., WTB., ENC., RTW.,
etc., for a FORTRAN logical unit number.
In previous versions of
FOROTS and FORTRAN-la, if the indirect bit was not set, the argument
was immediate; if it was set to 1 (one), the argument was the address
of the variable. The type field was always a (zero).
with Version 4 of FORTRAN-IO and Version 4 of FOROTS this convention
has been changed.
If the type field of the first word of an I/O
initialization call for the FORTRAN logical unit number is a (zero),
the argument is an immediate mode (18 bit) constant wherever possible.
If the type field is integer, the argument is indirect
(see Appendix
C, ~~able C,-l, Type 2).
This exception should not cause any upward compatibility problems,
since all previously working programs will still function. An added
feature with this convention is that it permits the following
construct to be correctly implemented:

100

D.6.3

N=-4
READ (N,lOO) I,J
FORMAT (215)

!SET FOR TERMINALS

MACRO Calls for FOROTS Functions

The following paragraphs describe the forms of the MACRO calls to
FOROTS that are made by the FORTRAN-IO compiler. The calls described
are identified according to the language statement
that
they
implement.
The following terms and abbreviations may be used in the
description of the argument block (ARGBLK) of each call:
pointer to the second word in the argument block.
(This
is the address pointed to by the argument ARGBLK in the
calling sequence.)
n

count of ASCII characters,

FORMAT statement address,

the name of an array containing ASCII characters,

list

an Input/Output list,

FOROTS

the statement to which control is transferred on an "END
OF FILE" condition,

the statement to which
"ERROR" condition,

name

a NAMELIST name,

a variable specifying
random access mode,

list directed I/O;

type

type specification of a variable or constant,

control

the

logical

transferred

record

number

for

the FORMAT statement is not used,

where ARGBLK is
_ _0-8

_~_ I_~~12~~~ [~~~_

18-35

-6
._---+--_.__ ..

Reserved

-.-.--~

-.-

type

Format Size

type

(in words)

D.6.3.l I/O statements, sequentia.~l~~A~c~c~e==s~s~~C~a==l=l=i~n~g~~S~.eque~f~~ - The
READ and WRITE statements for formatted sequential data transfer
operations and their calling sequences are:
READ(u,f,END=c, ERR=d)
MOVEI 16, ARGBLK
PUSHJ 17, IN.

list

WRITE(u,f,END=c, ERR=d)
MOVEI 16, ARGBLK
PUSHJ 17, OUT.

list

and

D-16

FORO'I'S
where ARGBLK is
18-35

-5
~-------

Reserved

- - - - - - - --

------.-

type

Format Size

(in words)

The READ and WRITE statements for unformatted sequential data transfer
operations and their calling sequences are:
READ(u,END=c, ERR=d)
MOVEI 16, ARGBLK
PUSHJ 17, RTB.

list

WRITE(u,END=c, ERR=d)
MOVEI 16, ARGBLK
PUSHJ 17, WTB.

list

and

where ARGBLK is

-3
~

Reserved

type

Reserved

--- --_._---

D.6.3.2 NAMELIST I/O, Sequential Access Calling Sequences - The READ
and WRITE statements for NAMELIST-directed sequentiai-~ata transfer
operations and their calling sequences are:
READ (u,name)
READ (u, name, END=c, ERR=d)
MOVEI 16, ARGBLK
PUSHJ 17, NLI.
and

....

WRITE (u, name)
WRITE (u, name, END=c, ERR=d)
MOVEI 16, ARGBLK
PUSHJ 17, NLO.
D-17

FOROTS
where ARGBLK is

0-8

9-12

14-17

18-35
--

-4

Reserved

type

Reserved

NAMELIST table address

The NAMELIST table is generated from the FORTRAN NAMELIST.
The
first
word of the table is the NAMELIST name;
following that are a number
of 2-word entries for scalar variables, and a
number
of
(N+3)-word
entries
for
array variables,
where N is the dimensionality of the
array.
The names you specify in the NAMELIST statement are stored, in SIXBIT
form,
first
in
the
table.
Each name
is
followed
by a list of
arguments a~3sociated with the name;
this argument list may be of any
length and 1s terminated by a zero entry.
The name argument list may
be in either a scalar or
an array
form
(refer
to the
following
diagrams) .

D.6.3.3 Array Offsets and Factoring - Address calculations. used
to
reference a given array element
involve factors and offsets.
For
example:
Array A is dimensioned
DIMENSION A (Ll/Ul,L2/U2,L3/U3, ... Ln/Un)
The size of each dimension is represented by
Sl = U1-Ll+l
S2 = U2-L2+l
etc.
In order to calculate the address of an element referenced by
A (Il,I2,I3, ... In)
the following formula is used:
A+(Il-Ll)+(I2-L2)*Sl+(I3-L3)*S2*Sl+ ... +(In-Ln)*S[n-l]* ... ~:S2*Sl
The terms are factored out depending on the dimensions of
and not on the element referenced to arrive at the formula

the

array

single

A+(-L-L2*Sl-L3*S2*Sl ... )+Il+I2*Sl+I3*S2*Sl ...
The parenthesized part of this formula is
the offset
for
precision array and it is referred to as the Array Offset.

D-18

FORo'rs
For each dimension of a given array, there is a
corresponding
factor
by which a
subscript in that position will be multiplied.
From the
last expression, one can determine the factor for dimension n to be
S[n-l]*S[n-2]* ... *S2*Sl
For double-precision and complex arrays, the expression becomes
A+2*(Il-Ll)+2*(I2-L2)*Sl+2*(I3-L3)*S2+Sl+ ...
Therefore, the array offset for a double-precision array is
2*(-Ll-L2*Sl-L3*S2*S1 ... )
and the factor for the nth dimension is
2*S[n-l]*S[n-2]* ... *S2*Sl
The factor for the first dimension of a
double-precision array is
always
2.
The
factor for the first dimension of a single-precision
array is always 1.
SCALAR ENTRY in a NAMELIST Table

SIXBIT/SCALAR NAME/

,.,
ARRAY ENTRY in a NAMELIST Table
18-35
SIXBIT/ARRAY NAME/
~.------------------

,..

#DIMS

type

1-----------,.------

ARRAY SIZE

OFFSET
I

Factor 1

Factor :2

Factor 3

Factor n

D-19

FOROTS
D.6.3.4
I/O Statements, Random Access Calling Sequences - The
READ
and WRITE statements for random access data transfer operations and
their calling sequences are:
READ (u#R,f,END=c, ERR=d) list
READ (u#R,END=c, ERR=d) list
MOVEI 16, ARGBLK
PUSHJ 17, RTB.
and
WRITE
WRITE
MOVEI
PUSHJ

(u#R,f,END=c, ERR=d) list
(u#R,END=c, ERR=d) list
16, ARGBLK
17, WTB.

where ARGBLK is

0-8~~_~~~~ __1~-1 7 __

18-35

-6

0
-------

Reserved

type

format size

address of
Record Number

Reserved
i

(in words)

--.~~-

f and the format size in words are 0 if the I/O statement is
unformatted.

D.6.3.5 Calling Sequences for Statements That Use Default Devices The FORTRru~-IO statements that require the use of a
reserved system
default device and their calling sequences are:
Default Device
ACCEPT f, list
READ f, list
REREAD f, list

(TTY)
(CDR)
(REREAD)

UNIT=-4
UNIT=-5
UNIT=-6

MOVE! 16, ARGBLK
PUSHJ 17, IN.

D-20

FORO']'S
whel:-e ARGBLK is

18-35
-5

---~

type

Reserved

Reser ved

----

- ---------

--~

------------

Format Size
(in words)

Default Device
PRINT f, list
PUNCH f, list
TYPE f, list

UNIT=-3
UNIT=-2
UNIT=-l

(LPT)
(PTP)
(TTY)

MOVEI 16, ARGBLK
PUSHJ 17, OUT.
where ARGBLK is
- - - - - - - - - -- --- - - - - - - - -

18-35

-5

0
----

Reserved

--"---"---

------------

type

X
"-------

D-21

format size

- ._-

-_._._-_._---

(in words)

FOROTS
D.6.3.6 Statements to Position Magnetic Tape Units - The
formatted
and unformatted FORTRAN-IO statements that may be used to control the
pO$itioning of a magnetic tape device and their calling sequences are:
Function
(FORTRAN Statement)

FOROTS Code

SKIPFILE (u)
BACKFILE (u)
BACKSPACE (u)
ENDFILE (u)
REWIND (u)
SKIPRECORD (u)
UNLOAD (u)

7
3

2
4

5
1

CALL:
MOVEI 16, ARGBLK
PUSHJ 17, MTOP.
where ARGBLK is

-4

0
r - - - - - - - --- --- --- ---------------------

Reserved

type

Reserved

type

FOROTS code

D.6.3.7 List Directed Input/Output Statements - You may write
any
form of a
sequential
Input/Output statement as a
list-directed
statement by replacing the referenced FORMAT statement number with an
asterisk
(*) .
The list-directed forms of the READ and WRITE
statements and their calling sequences are:
READ (u, *, END=c, ERR=d)

list

MOVEI 16, ARGBLK
PUSHJ 17, IN.
and
WRITE (u, *, END=c, ERR=d)

list

MOVEI 16, ARGBLK
PUSHJ 17, OUT.

D-22

FOROT'S
where ARGBLK is

0-8

==r

9-12

1-~-4~~

18-35

-5
----~

Reser'led

Reser\Ted

D.6.3.8 Input/Output Data Lists - The compiler generates a calling
sequence to the runtIme system if an I/O list is defined for the READ
or WRITE statement.
The argument block associated with the calling
sequence contains the addresses of the variables and arrays to be
transferred to or from an I/O buffer.
The general form of an I/O list
calling sequence is:
MOVEI 16, ARGBLK
PUSHJ 17, IOLST.
Any number of elements may be included in the ARGBLK.
The end of the
argument block
is specified by a zero entry or a call to the FIN.
entry.
FOROTS Value

Mnemonic Name
DATA
SLIST
ELIST
FIN

1
2
3
4

The elements of an I/O list are:

DA.TA
The DATA element converts one single- or double-precision or
complex
item from external
to
internal
form for a READ
statement and from internal to external
form for
a WRITE
statement.
Each DATA element has the following format.

___D_O:_:.A

1_ ::::

E~3
D-23

f_l_4-_:_17_-,--_S_C_A_:_:-:3_:oo -R

---1

FOROTS
2.

SLIST
The SLIST argument converts an entire array from internal
to
external
form or vice versa,
depending on the type of
statement, i.e., READ or WRITE, involved.
An SLIST table has
the following form:
0-8

9-12

14-17

#ELEMENTS

INCREMENT

BASE ADDR1.

_ _---_.-

18-35

SLIST

type

For example, the sequence:
DIMENSION A(100) ,B(100)
READ(-,-)A
or
READ(-,-) (A(I) ,1=1,100)

!on1y when the IOPT switch is used

develops an SLIST argument of the form:
0-8

9-12

[=4-17 I

a
a
a
a

18-35

a
2

a
a

144
1
A

a
--

._-----'--

More than one base address may appear in a SLIST as
the increment is the same.
The sequence
DIMENSION A(100), B(100)
WRITE (-,-) (A(I) ,B(I) ,1=100)

long

! only when the IOPT
switch is used

develops a SLIST argument of the form:

0-8

9-12

[_13

a
a

a
a
a
a
a

14-17

18-35

a
2

a
a
0
4

2
2

a
0

a
a
a

144
1
A
B
0
--

D-24

FOROTS
3.

ELIST
The SLIST format permits only. a single increment for a number
of arrays to be specified while the ELIST permits different
increments to be specified for different arrays.
The format of the ELIST is
0-8

9-12

14-17

18-35

r - - - - - - - - - - - - - ---.----- ---.--. - - - ..-.----.----

ELIST

No. Elements to
transfer
increment 1
Base ADDR 1
increment 2
Base ADDR 2
increment N
Base ADD.R N
._-----

For example, the FORTRAN sequence
DIMENSION IC(6,100), IB(100)
WR IT E ( - , - ) ( I B ( I) , I C ( 1 , I) , 1=1 , 100 )
produces the ELIST
9-12

0-8

-------

3
0
0
0
0
4
---

--~.

14-17

18-35

---------

0
0
0
0
0
0
2
0
0
0
0
0
2
0
0
0
0
0
---- --.-- - - - - - - -

The increment may be zero.
sequence
DIMENSION A(100)
WRITE(-,-) (K,I=100)

This could

- -

-_._--

144
1
IB
12
IC
0
--.~.-------

produced

-----

the

!only when the jOPT switch is used

The zero may not appear
as an
immediate constant
in the
argument block.
The ELIST for the previous example would be
,....------------r------9-12
0-8

14-17

18-35

r - - - - - - - - - - - . - ---...- ..

type

D-25

144
Pointer to a word
containing a zero

FOROTS
4.

FIN
The end of an I/O list is indicated by a
call
to
the
FIN
routine
in
the object time system.
This call must be made
after each I/O initialization call, including calls with a
null I/O list.
The FIN routine may be entered by an explicit
call or by an argument in the I/O list argument block.
If
both calls are used, the explicit call has no meaning.
The
FIN element has the following format:
EXPLICIT CALL:
PUSHJ 17, FIN.

0.6.3.9 OPEN and CLOSE Statements, Calling Sequences - The
form and
calling sequences for the OPEN and CLOSE FORTRAN-IO statements are:
OPEN STATEMENT CALL
MOVEI 16, ARGBLK
PUSHJ 17, OPEN.
CLOSE STATEMENT CALL
MOVEI 16, ARGBLK
PUSHJ 17, CLOSE.
where ARGBLK is

~~____L~-1~11~]~_4_-_l__7_+--_ _l_8_-_35_ _ _ _

---l

Negative of
the number
of words in
block not
including
this one.

o
---------"- - - - - - - 1 - - - - - - - - - - - - - - - -

0
0
0
G
G
G

type
type
type

I
I
I
I
I
I

type

2
7
7

X
X
X

c
d

X
X

H
H
H

-~----~-------------

The G field (bits 0 through 8) contains a 2-digit numeric that defines
the argument name;
the
H field
(bits
through 35) contains an
address which points to the value of the argument.

0-26

FOROTS
The numeric codes that may appear in the G field and the argument that
each identifies are:
G FiE~ld

Open Argument

G Field

01
02
03
04
05
06
07
10

DIALOG
ACCESS
DEVICE
BUFFER COUNT
BLOCK SIZE
FILENAME
PROTECTION
DIRECTORY

12
13
14
15
16
22
23
24

Open Argument
MODE
FILE SIZE
RECORD SIZE
DISPOSE
VERSION
ASSOCIATE VARIABLE
PARITY
DENSITY

D.6.3.l0 Memory Allocation Routines - The memory management module is
called
to allocate or de-allocate core blocks.
There are two entry
points,
ALCOR.
and
DECOR.,
that control memory allocation and
de-'allocation.
Use the ALCOR.
entry to allocate the number of words specified in the
argument block variable.
Upon return, AC 0 will contain either the
address of the allocated core block or a
-1 value,
which
indicates
that core is not available.
The calling sequence for ALCOR.
call is:
MOVEr 16, ARGBLK
PUSHJ 17, ALCOR.
where ARGBLK is
18-35

-1

Address of
Number of Words
Use the DECOR.
entry to de-allocate a previously allocated block of
memory;
the argument variable must be loaded with the address of the
core block to be returned.
Upon return AC 0 is set to O.
If the number of desired words is N,
ALCOR.
actually removes N+l
words from
free
storage.
The pointer returned points to the second
word (word 1 as opposed to word 0) removed from free storage.
The
0
word contains the negative value of N in its left half.
This word is
used by FOROTS to maintain linked lists of allocated
(using ALCOR.)
and free storage.
The calling sequence for a DECOR.

call is:

MOVEI 16, ARGBLK
PUSHJf 17, DECOR.

D-27

FOROTS
where ARGBLK is
9-12

0-8
-1

Reserved

_t_y_p_e__

---

~___I__~___ X

18-35

o
Pointer to word
containing
address of block
to be returned
------_.._---- .... _---_._-------------- ...----

0.6.3.11 Software Channel Allocation And De-allocation Routines - You
may allocate software channels in MACRO programs via calls to the
ALCHN. routine and de-allocate them by calls to the DECHN.
routine.
Values are returned in AC O.

Use the ALCHN. entry to allocate a particular channel or the next
available channel.
The channel to be allocated is passed to ALCHN.
in the argument block variable.
Zero is passed in the argument block
variable to allocate the next available channel. Allowed channE~ls are
1 through 17 (octal).
If the channel requested is not available, or
all channels are in use, ALCHN. returns with a -1 in AC O.
In normal
returns, AC 0 contains the assigned number.
The calling sequence of an ALCHN.

routine is:

MOVEI 16, ARGBLK
PUSHJ 17, ALCHN.
where ARGBLK is

0-8

I_9_-_1_2_-,--_1__3_-,--_1__4_-_1_7_ -f--- _ _ _1_8_-_3__5_ _ _ _ __

-1

ReserveI_t_y_p_e___

I__

- L_ _ _

-L_

Pointer to a word
containing
the channel #
or zero

---------- ------- ------ --------------------------

Use the DECHN. entry to de-allocate a previously assigned channel.
The channel to be released is passed to DECHN.
in the argument block
variable. If the channel to be de-allocated was not assigned by
ALCHN. and thus cannot be de-assigned, AC 0 is set to -Ion return.
The calling sequence for a DECHN.

routine is:

MOVEI 16, ARGBLK
PUSHJ 17, DECHN.

0-28

FOROTS
where ARGBLK is

O~~_2_J

14-17

--I

ResE'rved

type

I
D.7

18-35

Pointer to a word
containing
the channel #
to be released

.- -

FUNCTIONS TO FACILITATE OVERLAYS

interface with
FOROTS provides a subroutine (FUNCT.) to serve as an
the
LINK-IO overlay handler.
This subroutine consists of a group of
functions
that allow the overlay handler
to perform I/O,
core
management, and error message handling.
These functions have only one
entry point, FUNCT., and they are called by the sequence
MOVEI 16, ARGBLK
PUSHJ 17, FUNCT.
The general form of the ARGBLK is
18-35

0-17

.'
ARGBLK ----

Negative of the
number of words
in block
type
type
type
type
type
type

function number
error code
status
argument 1
argument 2
argument 3

type

argument n

I.. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _..L-._ _ _ _ _ _ _ _ _ _ _ ..._

where

tyP(?
function number
error code
status

the FORTRAN argument type (see Appendix C)
the number of one of the required functions
the 3-letter mnemonic output by the object
time system after
7,
%,
or [.
(See Table
D-l. )
undefined on the call and set on the
return
with one of the values below.
-1

l .... n

D--29

Function not implemented
Successful return
Specific error message

FOROTS
Table D-l
Function Numbers and Function Codes
,---------,...--_ __._.__ . _ - - - , - - _ ..__ ._-- - - - - - _ . _ - - - - - - - - - _ . _ - - - - - - - - - - ..

Function
Number

Function
Mnemonic

Function Description

----- ....-.--.-.-.- .--- . -

-----.--....- - - - - - - _ . _ - - - - - - - - - - - - - - - - - - - - - - - - - . _ - - - 1

8
9

ILL
GAD
COR
RAD
GCH
RCH
GOT
ROT
RNT
IFS

CBC

Illegal function
Allocates core from a specific addrE~ss
Allocates core from available core
De-allocates core
Gets or assigns an I/O channel
Releases an I/O channel
Allocates core from FOROTS
De-allocates core from FOROTS
Returns the initial runtime from FOROTS
Returns initial runtime file spec.
from
FOROTS
Cuts back core if possible

0
1

2
3
4
5
6
7

FUNCTION 0 (ILL) - This function is illegal.
The argument
ignored, and the function always returns a status of -1.
FUNCTION 1
(GAD) - This
function
address.
The arguments are:
arg 1
arg 2

allocates

core

from

block
a

specific

address at which to begin core allocation
number of words of core to allocate

The return statuses are:

o core allocated (arg 1 and 2 unchanged)
1 not enough core available in system (arg 1 and arg 2 unchanged)
2 cannot allocate core at specified address
(arg
1 and arg
2
unchanged)
3 illegal arguments (i.e., address + size is greater
than
256K)
(arg 1 and arg 2 unchanged)
FUNCTION 2 (COR)
arguments are:
arg 1
arg 2

- This function allocates core from any address.

The

undefined
size of core to allocate

The returned statuses are:

o core allocated

(arg 2 unchanged, arg 1 beginning address of the
allocated core)
1 not enough core available in system (arg 2 unchanged)
3 illegal argument (i.e., size is greater than 256K)
FUNCTION 3 (RAD) - This function de-allocates core
address.
The arguments are:
arg 1
arg 2

the

specified

and

the

size

address of core to be de-allocated
number of words to be de-allocated

The returned statuses are:

o core de-allocated
1 core cannot be de-allocated
3 illegal argument (i.e., both
greater than 256K)
D-30

the

address

are

FOROTS
FUNCTION 4 (GCH)
is:
arg 1

- This function assigns an I/O channel.

The argument

undefined

The returned statuses are:

o I/O channel assigned (arg 1 channel number)
1 no I/O channels available
FUNCTION
5
argument is:
arg 1

(RCH)

- This

function

releases

I/O

channel.

The

I/O channel number to be released

The returned statuses are:

o channel released
1 invalid channel number
FUNCTION 6 (GOT) - This function gets core from the object time system
list.
The arguments are:
arg 1
arg 2

address at which to allocate core
number of words of core to allocate

The returned statuses are:

o core allocated (arg 1 and arg 2 unchanged)
1 not enough core available in system (arg 1 and arg 2 unchanged)
2 cannot allocate core at specified address
(arg
1 and arg
2
unchanged)
3 illegal argument(s)
This function differs from function 1 in
that
if
the object
time
system has
two
free core lists, then function 1 is used to allocate
space for links, and this function is used to allocate space
for
I/O
buffers.
Function 1 uses the free core list for LINK-lO, and function
6 uses the list for the object time system.
FUNCTION 7 (ROT) - This function
system.
The arguments are:
arg 1
arg 2

returns

core

the

object

time

address of core to be de-allocated and returned
size of core to be de-allocated and returned

The returned statuses are:

o core de-allocated
1 core cannot be de-allocated
3 illegal argument
FUNCTION 8 (RNT) - This function returns the initial runtime from
object time system.
The argument is:
arg 1

undefined

The returned status is:

o always

(arg 1 - runtime from the object time system)

This function is used only if the user desires a log file.

D-31

the

FOROTS
FUNCTION 9(IFS) - This function returns the initial runtime file
specification from the object time system.
The specification is
obtained from accumulators 0, 7, and 11 after the initial RUN command.
The arguments are:
arg 1
arg 2
arg 3

undefined
undefined
undefined

The returned status is:

o always (arg 1 - device from accumulator 11, arg 2 - filename
from accumulator 0, and arg 3 - directory from accumulator 7)
This function tells the overlay handler which file to read
initial RUN command.

after

the

FUNCTION 10 (CBC) - This function cuts back core if possible and
used to reduce the size of the user job. There are no arguments.

The returned status is:

o always
D.B

LOGICAL/PHYSICAL DEVICE ASSIGNMENTS

You make FORTRAN logical and physical device assignments at run time,
or standard system assignments are made according to a FOROTS Device
Table,
i.e., DEVTB.
Table D-2 shows the standard
assignments
contained by the Device Table.

D-32

FOROTS
Table D-2
FORTRAN Device Table

Device/Function

REHEAD
CDH
TTY
LP'r
PTP
TTY
0
DSK
CDJR
LP'r
CTY
TTY
PTR
PTP
DIS
DTAI
DTA2
DTA3
DTA4
DTA5
DTA6
DTA7
MTAO
MTAI
MTA2
FORTR
DSK
DSK
DSK
DSK
DSK
DEVI
DEV2

FORTRAN Logical
Unit Number

DEV3
DEV4
DEV5

-6
-5
-4
-3
-2
-1
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

DEV39

Use
REREAD statement
READ statement
ACCEPT statement
PRINT statement
PUNCH statement
TYPE statement
ILLEGAL
DISK
Card Reader
Line Printer
Console Teletype
User's Teletype
Paper Tape Reader
Paper Tape Punch
Display
DECtape
DECtape
DECtape
DECtape
DECtape
DECtape
DECtape
Magnetic Tape
Magnetic Tape
Magnetic Tape
Assignable Device
DISK
DISK
DISK
DISK
DISK
Assignable Devices

D-33

APPENDIX E
FORDD'1~

FORDDT is an interactive program used to debug FORTRAN programs and
control
their execution.
By using the symbols created by the FORTRAN
compiler, FORDDT allows you to examine and modify the data and
FORMAT
statements
in your program,
set breakpoints at any executable
statement or routine, trace your program statement-by-statement,
and
make use of many other debugging
techniques described
in this
appendix.
Table E-l lists all the commands available to the user of FORDDT.
Table B-1
Table of Commands
Command

Purpose

------------

Data Access Commands
ACCEPT

Modifies data locations.

TYPE

Displays data locations.

Declarative Commands
GROUP

Defines indirect lists for TYPE statements.

MODE

Specifies format of typeout.

OPEN

Accesses program unit symbol table.

PAUSE

Places pause requests.

HEMOVE

Removes pause requests.

DIMENSION

Defines dimensions of arrays for
references.
(Unnecessary
/DEBUG:DIMENSIONS was used.
See

FORDDT
if
Table

B-2. )

DOUBLE

Defines dimensions
of
double-precision
arrays for FORDDT references.
(Unnecessary
if /DEBUG:
DIMENSIONS was used.
See Table
B-2. )

E-l

FORDDT
Table E-l (Cont.)
Table of Commands
Command

Purpose
-.. - - - - - - - - -..- - - - - - - 1

Control Commands
START

Begins execution of FORTRAN program.

CONTINUE

Continues execution after a pause.

GOTO

Transfers control to some program statement
within the open program unit.

Traces execution of the program.

STOP

Terminates program and returns
mode.

DDT

Enters DDT (if DDT is loaded).

monitor

Other Commands
LOCATE

Lists program unit names in which
symbol is defined.

STRACE

Displays
routine
program status.

WHAT

Displays current
DIMENSION,
PAUSE information.

E.l

backtrace

given
current

GROUP,

and

INPUT FORMAT

fORDD~ commands are made up of alphabetic FORTRAN-like identifiers and
need consist of only
those characters required to make the command
unique.
If you wish to specify parameters, a space or tab is required
following the command name.
FORDDT expects a parameter if a delimiter
(i.e., space or tab) is found.
Comments may be appended
to command
lines by preceding the comment with an !.

E.l.l

Variables and Arrays

FORDDT allows you to access and modify
the data
locations
in your
program by using
standard FORTRAN-IO symbolic names.
Variables are
specified simply by name.
Array elements are
specified
in
the
following format:
name

(Sl, ... ,Sn)

where
name
(Sl, ... ,Sn)

a FORTRAN variable or array name
the subscripts of the particular array.

You may reference an entire array simply by
its unsubscripted
name;
you may specify a range of array elements by inputting the first and
last array elements of the desired range, separated by a dash(-).

E-2

FORDD~~

Examples
ALPHA
ALPHA(7)
ALPHA (PI)
ALPHA(2)-ALPHA(5)

£.1.2

Numeric Conventions

FORDDT accepts optionally
FORTRAN-IO input formats:

signed

numeric

data

the

standard

INTEGER - A string of decimal digits.

FLOATING-POINT
A string of decimal digits optionally
including
a
decimal
point.
Standard engineerin9
and
double-precision exponent formats are also accepted.

OCTAL - A strin<j of octal digits
double quote (II).

COMPLEX - An ordered
pair
of
integer
or
real
separated by a comma and enclosed in parentheses.

E.l.3

optionally

preceded

constants

Statement Labels and Source Line Numbers

FORTRAN statement labels are
input
and
output by straightforward
numeric
reference,
i.e., 1234.
However, source line numbers must be
input to FORDDT with a number sign (#) preceding them.
This mandatory
sign distinguishes statement labels from source line numbers.

E.2

NEW USER TUTORIAL

The new FORDDT user can rely on the commands described
below as
a
basis
for
debugging
FORTRAN programs.
These commands are easy to
understand and apply.

E.2.1

Basic Commands

The easiest method of loading and starting FORDDT is:
.DEBUG filename.ext

(DEBUG)/FIO

FORDDT will respond with
ENTERING FORDDT

Just as an aster isk (*)
signifies
FORTRAN-IO's
readiness,
the
two
angle brackets signify that FORDDT is awaiting one of the following
commands:
OPEN

Makes available
to
FORDDT the
symbol
names
in a
particular program unit of the FORTRAN program.
When a
program unit symbol table
is opened,
the previously
E-3

FORDDT
open program unit is automatically closed.
When FORDDT
is entered, the MAIN program is automatically opened.
The command format is:
OPEN name
This will open the particular program unit named
und
allow all
variables within
that
subprogram to
be
accessible to FORDDT.
OPEN

START

with no arguments will reopen the symbol table
main program unit.

Starts your program at the main
The command format is:

point.

pro3ram

entry

the

START
STOP

Terminates program execution, causes all
files
to
be
closed,
and
exits to the monitor.
The command format
is:
STOP

MODE

Defines the display format for succeeding
FORGOT TYPE
commands.
You need
type only the first character of
the mode to identify it to FORDDT.
The modes are:
Mode
A
C
D
F
I

Meaning
ASCII (left-justified)
COMPLEX
DOUBLE-PRECISION
FLOATING-POINT
INTEGER
OCTAL
RASCII (right-justified)

Unless the MODE command is given, the
mode is the floating-point format.

default

typeout

The command format is:
MODE list
where list contains one or more of the mode identifiers
separated by commas.
The current setting can be
changed by issuing another MODE command.
If more
than
one mode
is given,
the values are typed out in the
order:
F,D,C,I,O,A,R
MODE
with no arguments will reset
FORDDT
setting of floating-point format.
TYPE

the

original

Allows you to display the contents of one or more data
locations.
They
are displayed on your
terminal
formatted according to
the last MODE specification.
The command format is:
TYPE list

E-4

FORDD'I'
where list may contain one or more
arrays,
variables,
array elements,
or
array element ranges separated by
commas.
For example:
TYPE I, ALPHA, BETA ( 2) ,J ( 3) -J (5)
Each item will be displayed in each of
the currently
active typeout modes as set by the last MODE command.
ACCEPT

Allows you
to
change
the contents of a
FORTRAN
variable, array, array element, or array clement range.
The command format is:
ACCEPT name/mode value
where
name

the name of
the variable,
array,
array
element,
or
array element
range
to be
modified.
If
the
field
contains
an
unsubscripted
array name or
an element
range, it causes all the
elements
to
be
set
to
the given value (see special case
for ASCII in Section f.6).

mode

the
format
of
the data value
to
be
entered.
If given, it must be preceded by
a slash (/)
and
immediately follow
the
name.
(Note that /mode does not apply to
FORMAT modification.)

value

the new val ue to
be assisneJ.
It must
correspond in format to the given mode.
Data Modes

You need type only the first character of a
data mode
to
identify
it
to
FORDDT.
If not
specified, the
default mode is REAL.
The following
input modes are
available:
Mode

Meaning

ASCII(left-justified)
COMPLEX
DOUBLE-PRECISION
REAL
INTEGER
OCTAL
RASCII(right-justified)
SYMBOLIC

C
D
F
I

o
R
S

Example
/FOO/
(1.25,-78.E+9)
123.4567890
123.45678
1234567890
76543210
\BAR\
PSI(2,4)

An example of the ACCEPT command format is:
ACCEPT ALPHA 100.6
This changes the value of the variable ALPHA to
100.6
with the default input mode of REAL, since mode was not
specified.
PAUSE

Allows you to set
a
breakpoint at any label,
line
number,
or
subroutine entry in your program.
You may
set up to ten pauses at one time.
When one of these
pauses is encountered, execution of the FORTRAN program
E-5

FORDDT
is suspended and control is transferred to FORDDT.
Also, when a pause is encountered, the symbol table of
that subprogram is automatically opened.
The commanJ
fc.)['lat

is:

PAUSE P
where P is a statement label number, line
routine entry point name;
for example,

number,

PAUSE 100
will cause a breakpoint at statement label 100
currently open program unit.

the

Note that subprogram parameter values will be displayed
when a pause is encountered at a subprogram entry
point.
CONTINUE

Allows the prograln to resume execution after a FORDDT
pause.
After a CONTINUE is executed, the program
either runs to completion, or
it runs until another
pause is encountered.
If you include a value with this
command, t.he pro9ra,o will run until the nth occurrence
of the given pause or until a different pause is
encountered. The command formats are:
CONTINUE
or
CONTINUE n
Example
CONTINUE 15
will continue execution until the fifteenth
of the pause.

REMOVE

occurrence

Used to remove those pauses from the program previously
set up by the PAUSE command. The command format is
REMOVE P
where P is the number of the statement label where
pause was set, i . e . ,

the

REMOVE 100
will re:nove the pause at statement label 100.
Note that REMOVE with no arguments will remove all
pauses;
therefore,
no abbreviation of the command is
allowed in this instance. This precaution prevents the
accidental removal of all pauses.
WHAT

Displays on your terminal the name of the currently
open program unit and any currently active pause
settin~s.
The command format is:
WHAT

E-6

FORDDT
E.3

FORD[~AND

!HE

FORTR?\N-IQLDJ~_~~

Most facilities of FORDDT are
features;
however, if you do
a FORTRAN program, the trace
available, and several of the

SWITCH

available without the FORTRAN-IO /DEDUG
not use the /DEBUG switch when compiling
features
(NEXT command)
will
not
be
other commands will be restricted.

Using the /DEBUG switch tells FOI~TRAN-IO to compile extra
information
for
FORDDT.
(See
Appendix
D,
Using
the Compiler, for a complete
description of each feature.) The additional features include:
1.

/DEBUG:DIMENSIONS, which will generate dimension
inform?tion
to the REL file for all arrays dimensioned in the subprogram.
The dimension information will automatically be available
to
FORDDT
if you wish to reference an array in a Type or ACCEPT
command.
This
feature
eliminates
the need
to
specify
ciimension
information
for
FORDDT by using
the DIi1ENSION
command.

/DEBUG:LABELS,
which will
generate
labels
for
every
executable source line in the form 1I1ine-number LII.
If these
labels are generated, they may be used as arguments with
the
FORDDT commands PAUSE and GOTO.
This switch will also generate labels at
the last
location
allocated
for
a
FORMAT statement so that FORDDT can detect
the end of the statement.
These
labels have
the
form
"format-label FII.
If they are generated, you will be able to
display and modify FORMAT statements via the TYPE and ACCEPT
commands.
Note that the :LA3ELS switch is automatically activated with
che
:TRACE switch, since labels are needed to accomplish the
trace features.

/DEBUG:TRACE, which will generate a
reference
to
FORDDT
before each executable statement.
This switch is required
for the trace command NEXT to function.
Note that if more than one FORTRAN statement has been placed
on a single input line, only the first statement will have a
FORDDT reference and line-number label
associated
with
it.
This also applies to the :LABELS switch.

/DEBUG:INDEX, which will force the compiler to store
in
its
respective data location as well
as a register the index
variable of all DO loops at
the beginning of each loop
iteration.
You will
then be able to examine DO loops by
using FORDDT.
If you modify a DO loop index using FORDDT, it
will
not affect
the number
of
loop iterations because a
separate loop count is used.
(See Section 0.1.5.)
Note that this switch has no direct
in FORDDT.

affect

any

the

FORDDT

with

~ommands

E.4

LOADING AND STARTING FORDDT
1.

The simplest method of loading and starting
the following command string:
.DEBUG filename.ext(DEBUG)/FlO

E-7

FORDDT
FORDDT responds with
ENTERING FORDDT

»
The angle brackets indicate that FORDDT is ready to receive a
command,
just as
an asterisk
(*)
signifies FORTRAN-la's
readiness.
The DEBUG command to the monitor will also load DDT (standard
system debugging program).
DDT can be used or ignored, but
it does require an extra 2K (octal) of core.
2.

You may wish
to
load
your
compiled program and
FORDDT
directly with the LINK-l a loader.
(Loading with LINK-IO was
accomplished implicitly in the previous command string.)
The
command sequence is as follows:
.R LINK
*filename.ext /DEB/G
*filename.ext /DEb:
FORDDT
FORTRA
*filename.ext /DEB: (DDT,

(loads DDT)
(loads FORDDT)

FORDDT
FORTRA

)/G

loads both DDT
and FORDD'f

If the total FORTRAN program consists of many subroutines and
insufficient core
is available
to complete loading with
symbols, it is possible
to
load with
symbols
just
those
sections expected
to give trouble.
The remaining routines
need not be loaded.

E.5

SCOPE OF NAME AND LABEL REFERENCES

Each program unit has its own symbol table.
When you initially enter
FORDDT,
you automatically open the symbol table of the main program.
All references to names or labels via FORDDT must be made with respect
to
the currently open symbol
table.
If you have given the main
program a name other than MAIN by using
the
PROGRAM statement
(see
Chapter 5, Section 5.2), FORDDT will ask for the defined program name.
After you enter the program name, FORDDT will
open
the appropriate
symbol table.
At this point, symbol tables in programs other than the
main program can be opened by using the OPEN command.
(See Section
F. 5. )
References to statement labels,
line numbers,
FORMAT statements,
variables,
and arrays must
have
labels
that are defined in the
currently open symbol table.
However, FORDDT will accept variable and
array references outside
the currently open symbol table, providing
the name is unique with respect to all program units in the given load
module.

E.6

FORDDT COMMANDS

This section gives a detailed description of all commands
The commands are given in alphabetical order.

£-8

FORGDT.

FORDDT
l\CCEPT

Allows you to change the contents of a
FORTkAN
array,
array element,
array element
range,
statement.
The command format is:

variable,
or FORMAT

ACCEPT name/mode value
where
name

the

variable
array,
array element,
range,
or
FORMAT statement
modified.
cle~ent

array
to be

mode

the forJ1lat of the data value
to be entered.
The mode
k~yword must be preceded by a slash
and
immediately
follow
the
name.
(/)
Intervening
blanks are not allowed.
(Note
that /mode
FORMAT
does
not
apply
to
modification.)

value

the new value to be assigned.
The
format
of
input
value must correspond
to
the
the
specified :llode.
DATA LOCATION MODIFICATION
Data Hodes

The following data modes are accepted:
Hode

Meaning
ASCII (left-justified)
COMPLEX
DOUBLE-PRECISION
REAL
INTEGER
OC'I'AL
RA SCI I ( rig h t - jus t i fie d )
SYMBOLIC

A
C
D
F
I

o
R
S

Example
/FOO/
(1.25,-78.E+9)
123.4567890
123.45678
1234567890
76543210
\BAR\
PS I (2,4)

If not specified, the default mode is REAL.
Two-Word Values

....

For the data modes ASCII,
RASCII,
OCTAL,
and
SYMBOLIC,
FORDOT will accept a "/LONG" modifier on the mode switch.
This modifier indicates that the variable and
the value
are to be interpreted as two words long.
Exat:1pl'2
ACCEPT VAR/RASCII/LONG '1234567890'
will assume that VAR is two words long and store the given
lO-character literal into it.
Initialization of Arrays
If the name field of an ACCEPT contains an
unsubscripted
array name or a range of array elements, all elements of
the array or the specified range will be set to the given
value.

E-9

FORDDT
Example
ACCEPT ARRAY/F 1.0
or
ACCEPT ARRAY(5)-ARRAY(10)/F 1.0
Note that this applies only to modes other than ASCII
RASCII.

and

Long Literals
When

the

value
field
of
an
ACCEPT
contains
an
array name or range of array elements, and
the specified data InoQe is ASCII or
RASCII,
the value
field
IS
expected
to contain a
long literal string.
ACCEPT will store the string linearly into the array or
array range.
If the array is not filled, the remainder of
the array or range will be set to zero.
If the literal is
too long the remaining characters will be ignored.
unsu~scripted

Example
ACCEPT ARRAY/RASCII

'ABCDEFGHIJKLIvlNOPQRSTUVWXYZ'

FORMAT STATEMENT MODIFICATION
When the name field of an ACCEPT contains a label,
FORDDT
expects this label to be a FORMAT statement label and that
the value field contains d new FORMAT specification.
Example
ACCEPT 10 (lHO,FIO.2,3(I2))
The new specification cannot be
longer
than the
space
originally allocated
to the FORMAT by the compiler.
The
remainder of the area is cleared if the new specification
is shorter.
Note
that
FOROTS performs some encoding
of
FORMAT
statements when it processes them for the first time.
If
any I/O statement referencing the given FORMAT has been
executed,
the
FORTRAN program has
to be restarted
(re-initializing FOROTS).
CONTINUE

Allows the program to
resume execution after
a
FORDDT
pause.
After
a CONTINUE is executed, the program either
runs to completion or until another pause is encountered.
The command format is:
CONTINUE n
where the n is optional and, if omitted, will
be assumed
to be one.
If a value is provided, it may be a numeric
constant or program variable, but it will be treated as an
integer.
When the value n is specified, the program will
continue execution until the nth occurrence of this pause.
For example,
CONTINUE 20
will continue execution after the 20th occurrence
pause.

E-IO

the

FORDDT
DDT

Transfers control of the
pro'jralll
to
DDT,
the
standard
system debugging pro':]ra1n (if loaded).
Any files currently
opened by FOROTS are unaffected and return
to
rORDDT
is
possible so that program execution [;tay be resumed .
symbol
llsed
. FIO is the global
FORDDT.
The command format is:

return

control

.FIO$G
where $ represents altmode or escape.
Your
program will
be
in
the
same condition
as
before
unless
JOU have
modified your core image with DDT.
DIMENSION Sets the user-defined dimensions of an array
for
FORDDT
access purposes.
These dimensions
need not agree with
those declared to the compiler in the source code.
FORGDT
will
allow you
to redimension an array to have a larger
scope than that of the source program.
If this is done, a
warning is given.
The command format is:
DIMENSION S
where S is the name of the array specified.
For example:
DIMENSION ALPHA(7,5/6,lO)
FORDDT will remember the dimensions of the array until
is redefined or removed.

The command
DIMENSION
will give a full list of all the
for all arrays.

user-defined

dimensions

DIMENSION ALPHA
will display the current information for
only.

the

array

ALPHA

DIMENSION ALPHA/REMOVE
will remove any user defined
array ALPHA.

array

information

for

the

Arrays, Array Elements, and Ranges
Array elements are specified in the following format:
name

[dl/d2, ... ](Sl, ... )

where
name
[

... ]

the name of the array
optional, and contains dimension
information.
This
form
is equivalent
in effect
to the
DIMENSION statement.

E-ll

FORDDT

(

... )

the
subscripts
desired.

the

specific

element

The entire array is referenced simply by its unsubscripted
name.
A range of array elements is specified by inputting
the first and last array elements of the desired
range
separated by a dash (-) (A(5)-A(lO)).
DOUBLE

Defines the dimensions of a double-precision array.
The
result of
this command is the same as for the DIMENSION
command except that the array so dimensioned is understood
by FORDDT to be an array with word entries and, therefore,
reserves twice the space.
The command format is:
DOUBLE arrayname

GOTO

Allows you to continue your program from a
point other
than the one at which it last paused.
The GOTO allows you
to continue at a statement label or code-generating source
line number
provided
that
the /DEBUG:LABELS switch has
been used or the contents of a symbol previously ASSIGNed
during the program execution.
Note that the program must be STARTed before this command
can be used,
and
also
note that a GOTO is not allowed
after the ~C~C REENTER sequence.
(See F.6.)
The command format is:
GOTO n

GROUP

Sets up a string of text for input to a TYPE command.
You
can
store
TYPE statements as a
list of variables
identified by the
numbers
1 through
8.
This
feature
eliminates
the
need to retype the same list of variables
each time you wish to examine the same group.
Refer
to
the TYPE command for the proper format of the list.
The command format is:
GROUP n list
where
n

the group number 1-8

list

a string of TYPE statements to be called
in
future accessing of the current group number.

GROUP
with no arguments will
cause
FORDDT
current contents of all the groups

type

out

the

GROUP n
will
type
requested.

out

the

contents

the

Note that one group may call another.

E-12

particular

group

FORDDT
LOCATE

Lists the program unit names in which a
given
symbol
is
defined.
This
is
useful
when the variable you wish to
locate is not in the currently open program unit
and
is
~efined in more than one program unit.
The command format
is:
LOCATE n
where n may be any FORTRAN variable,
number, or FORMAT statement number.

MODE

array,

label,

line

Defines the default formats of typeout
from
FORDDT.
In
initial
default
mode,
variables will
be
typed
in
floating-point format.
If you wish to change the
typeout
modes, the command format is:
MODE list
where list contains one or
nore of
the modes
in
the
following
table.
(Only the first character of each mode
need be typed to identIfy it to FORDDT.)
Mode
F
D
C
I

A
R

Meaning
FLOATING-POINT
DOUBLE-PRECISION
COMPLEX
INTEGER
OCTAL
ASCII (left-justified)
RASCII (right-justified)

A typical command string might be:
MODE A,I,OCTAL
NEXT

Allows you
to cause
FORDDT to
trace
source
lines,
statement labels,
and entry point names during execution
of your program.
This command will only provide
trace
facilities if the program was compiled with the FORTRAN-IO
If this switch was not
used,
the
NEXT
/DEBUG switch.
command will
act as
a
CONTINUE command.
The command
format is:
NEXT n/sw
where
n

a program variable or
and

integer

one of the following switches

numeric

value

/S= statement label
/L= source line
/E= entry point
The default starting value of n is 1, a
trace.
The default switch is /L.
The command
NEXT 20/L

E-13

single

statement

FORDDT
will trace the execution of
the next
20 source
numbers or until another pause is encountered.
Note that if no argument is specified, the
given will be used.
For example,

last

line

argument

NEXT /E
will change the tracing mode
to trace only subprogram
entries using the numeric argument previously supplied.
OPEN

Allows you to open a particular program unit of the loaded
program so
that
the variables will
be accessible to
FORDOT.
Any previously opened program unit
is closed
automatically when a
new one
is opened.
Only global
symbols, symbols in the currently open unit,
and
unique
locals are available at anyone time.
Note that starting
FORDDT automatically opens the MAIN program.
The command
format is:
OPEN name
where name is the subprogram name.
will reopen the MAIN program.

OPEN with no arguments

If the PROGRAM statement was used in the FORTRAN program,
the name
supplied by you will be requested upon entering
FORDDT.
PAUSE

Allows you to place a pause request at a statement number,
source line number, or subroutine entry point.
Up to ten
pauses may be set at anyone
time.
When a pause
is
encountered,
execution
is suspended at
that point and
control is returned to FORDDT.
Also,
when a pause
is
encountered,
the symbol
table of that subprogram is
automatically opened.
The command formats include:
PAUSE
PAUSE
PAUSE
PAUSE
PAUSE
PAUSE

P
P AFTER n
P IF condition
P TYPING /g
P AFTER n TYPING /g
P IF condition TYPING /g

where
P

the point where the pause is requested,
an
integer
constant or
variable or
element
a group number

array

PAUSE 100
will set a pause at statement label 100,
cause execution
to be suspended,
and cause FORDDT to be entered on
reaching 100 in the program.
PAUSE #245 AFTER MAX(5)
will cause a pause to occur
at source line number
245
after
encountering
this point the
number
of times
specified by MAX(5).
Note
that AFTER may
not
be
abbreviated.
E-14

FORDDT
PAUSE DELTA IF LIMIT(3,l) .GT.2.5E-3
If the variable
LIMIT(3,l)
is greater
than
the
value
2.5E-3, the pause request will be granted.
The IF may not
be abbreviated,
but all
the
usual
FORTRAN
logical
connectives are allowed.
PAUSE 505 TYPING /5
will request a pause to be made at the first occurrence of
the
label
505,
and
the
variables
in group 5 will be
displayed.
The
TYPING
specification
may
not
be
abbreviated.
PAUSE LINE#24 AFTER l6 TYPING 3
will place a request at source line number
24 after
16
(octal)
times
through;
however, the contents of group 3
will be displayed every time.
When the TYPING option is used
with
the
PAUSE command,
control
can be transferred to FORDDT at the next typeout
by typing any character on the terminal.
Note that pause requests remain after a control C REENTER
sequence, a START command, or a control C START sequence.
REMOVE

Removes the
format is:

previously

requested

pauses.

The

command

REMOVE P
For example,
REMOVE L#123
will remove a pause at program source line number 123.
REMOVE ALPHA
will remove a pause at the subroutine entry to ALPHA.
REMOVE with no arguments will
remove
all
your
pause
requests,
and, in this case, no abbreviation of REMOVE is
allowed.
This prevents
the
unintentional
removal
of
pauses.
S'I'ART

Starts your program at the
normal
FORTRAN
entry point.
The command format is:

main

program

START
S'I'OP

Terminates the program, requests FOROTS to close all open
files,
and causes an exit
to
the monitor.
The usual
command format is:
STOP
STOP/RETURN
will allow a return
to monitor mode without
releasing
devices or closing files so that a CONTINUE can be issued.

E-15

FORDDT
STRACE

Displays a subprogram level backtrace of the current state
of the program. The command format is:
STRACE

TYPE

Causes one or more FORTRAN defined variables, arrays, or
array elements to be displayed on your terminal. The
command format is:
TYPE list
where list may be one or more variable or array references
and/or
group numbers.
These specifications must be
separated by commas, and group numbers must be preceded by
a slash
(/). The command with no arguments will use the
last argument list submitted to FORDDT.
An array
example:

element

range

can

also

specified.

For

TYPE PI(5)-PI(13)
will display the values from PI(5)
to PI(13)
inclusive.
If an unsubscripted array name is specified, the entire
array will be typed.
There are several methods of choosing the form of
in conjunction with the MODE command.
a

format,

If you do not specify
floating-point form.

You can specify a format via
described in this appendix.

You can change the format previously designated
by the MODE command by including print modifiers
in the TYPE or GROUP string. The print modifiers
are:

the

typeout

MODE

defaultis
command

/A,/C,/D,/F,/I,/O,/R
The first print modifier specified in a string of
variables determines the mode for
the entire
string unless another mode is placed directly to
the right of a particular variable. For example,
in
TYPE /IK,L/O,M,N/A,/2
the typeout mode is integer until another mode is
specified. Therefore,
K,M,and/2
OCTAL
N = ASCII

= Integer

WHAT

Displays the information saved
format is:
WHAT

E-16

FORDDT.

The

command

FORDDT
E.7

ENVIRONMENT CONTROL

If a program enters an indefinite loop, you can recover by typing a
REENTER sequence.
This action will cause FORDDT to simulate a
pause at the point of reentry and allow you to control your
run-away
program.
~C~C

Most commands can be used once the program has been reentered;
however,
GOTO,
STRACE, TYPE, and ACCEPT cause transfer of control to
routines external to FORDDT.
No guarantee can be made to ensure that
any of these commands following
a
~C"C REENTER sequence will not
destroy the user profile. The program must be returned to a stable
state before any of these four commands can be issued.
In order to
restore program integrity, you should set a pause at the next label
and then CONTINUE to it.
If the /DEBUG:TRACE switch was used, a NEXT
I command can be issued to restore program integrity.

E.8

FORTRAN-IO/OPTIMIZE SWITCH

-----------------

You should never attempt to use FORDDT with a program that has been
compiled with the /OFTIMIZE switch.
The global optimizer causes
variables to be kept in ACs.
For this reason, attempts to examine or
~odify variables in optimized programs will not work.
Also, since the
optimizer moves statements around in your program, attempts to trace
program flow will lead to great confusion.

E.g

FORDDT MESSAGES

PORDDT responds with two levels of messages - fatal error and warning.
Fatal error messages indicate that the processing of a given command
has been terminated. Warning messages provide helpful
information.
The format of these messages is:
?FDTXXX text
or
%FD'I'XXX text
where
?

fatal
warning
FORDDT mnemonic
3-letter mnemonic for error message
explanation of error

FDT
XXX
text

Square brackets ([ ]) in this section signify variables
output on the terminal.

and

are

not

rata,l Errors
The fatal errors in the following list are each preceded by ?FDT on
the user
terminal and on listings.
They are listed in alphabetical
order.
BDF

[symbol]

BOI

BAD OCTAL OUTPUT

IS UNDEFINED OR IS MULTIPLY DEFINED

An illegal character was detected in an octal input value.

E-17

FORDDT

ceN

CANNOT CONTINUE
Pause has been placed on
some
form of skip instruction
causing
FORDDT to loop;
should never be encountered in
FORTRAN-IO compiled programs.

CFO

CORE FILE OVERFLOW
The storage area for GROUP text has been exhausted.

CNU

THE COMMAND [name]

IS NOT UNIQUE

More letters of the command are required to
from the other commands.
CSH

acceptable

FORTRAN-IO

DIMENSION TABLE OVERFLOW
FORDDT does not have the space
to
dimensions until some are removed.

FCX

CANNOT START HERE
The specified entry point is not
main program entry point.

DTO

distinguish

record

any

array

FORMAT CAPACITY EXCEEDED
An attempt was made to specify a FORMAT statement
requiring
space than was originally allocated by FORTRAN-IO.

~ore

FNI

FORMAL NOT INITIALIZED
Reference to a FORMAL parameter of some subprogram that
never executed.

FNR

[array name]

was

IS A FORMAL AND MAY NOT BE RE-DEFINED

FORMAL parameters may not be DIMENSIONed.
IAF

ILLEGAL ARGUMENT FORMAT
The parameters to
the given command were
not specified
properly.
Refer to the documentation for correct format.

IAT

ILLEGAL ARGUMENT TYPE

= [number]

An unrecognized
subprogram argument
Submit an SPR if this message occurs.
ICC

type

was

detected.

COMPARE TWO CONSTANTS IS NOT ALLOWED
Conditional test involves two constants.

IER

E (number)
Internal FORDDT error - please report via an SPR.

IGN

INVALID GROUP NUMBER
Group numbers must be integral and in the range I through B.

INV

INVALID VALUE
A syntax error was detected in the numeric parameter.

E-IB

FORDDT
ITM

ILLEGAL TYPE MODIFIER - S

The mode S is only valid for ACCEPT statements.
LGU

[array name] LOWER SUBSCRIPT.GE.UPPER
The lower bound of any given dimension must be less than
equal to the upper bound.

LNF

(label] IS NOT A FORMAT STATEMENT

MLD

[array name] MULTI-LEVEL ARRAY DEFINITION NOT ALLOWED

The same array cannot be dimensioned more than once (via the
[dimensions] construct) in a single command.
MSN

MORE SUBSCRIPTS NEEDED

The array is defined to have more
specified in the given reference.
NAL

dimensions

than

were

NOT ALLOWED

An attempt has been made to modify something other than data
or a FORMAT.
NAR

NOT AFTER A RE-ENTER

rrhe given command is not allowed until program integrity has
been restored via a CONTINUE or NEXT command.

NDT

DDT NOT LOADED

NFS

CANNOT FIND FORTRAN START ADDRESS FOR [program name]

Main program symbols are not loaded.
NFV

[symbol] IS NOT A FORTRAN VARIABLE
Names must be 6-character
with a letter.

alphanumeric

NGF

CANNOT GOTO A FORMAT STATEMENT

NPH

CANNOT INSERT A PAUSE HERE

strings

beginning

An attempt has been made to place a pause at other
executable statement or subprogram entry point.
NSP

[symbol] NO SUCH PAUSE
An attempt has been made to REMOVE a pause
set up.

NUD

than

that

was

never

[symbol] NOT A USER DEFINED ARRAY
An attempt has been made to remove dimension information for
an array that was never defined.

PAR

PARENTHESES REQUIRED ( .. )

Parentheses are required for the
statements and complex constants.

E-19

specification

FORMAT

FORDDT
PRO

TOO MANY PAUSE REQVSSTS
The PAUSE table has been exhausted.
10.

SER

The

maximum

limit

SUBSCRIPT ERROR
The subscript specified is outside the range of its
dimensions.

STL

[array name]

define

array

larger

than

TOO MANY SUBSCRIPTS
The array is defined
to have
fewer
dimensions
specified in the given element reference.

URC

defined

SIZE TOO LARGE

An attempt has been made to
256K.
TMS

than

are

UNRECOGNIZED COMMAND

Warning Messages
Each warning message in this list is preceded by %FTN on your terminal
and on listings.
They are given here in alphabetical order.
ABX

[array name] COMPILED ARRAY BOUNDS EXCEEDED
FORDDT has detected another symbol defined in the specified
range of the array.
Note that this will occur in certain
EQUIVALENCE cases and can be ignored at that time.

CHI

CHARACTERS IGNORED:

[text] II

The portion of the command string
included
thought to be extraneous and was ignored.
NAR

[symbol]

NSL

NO SYMBOLS LOADED

"text"

was

IS NOT AN ARRAY

FORDDT cannot find the symbol table.
NST

NOT STARTED
The specified command requires that a
START be previously
issued to ensure that the program is properly initialized.

POV

PROGRAM OVERLAYED
The symbol table is different from the last time FORDDT
control.

SFA

had

SUPERSEDES FlO ARRAY
The FORTRAN-IO generated dimension is being
the given array.

SPO

VARIABLE IS SINGLE-PReCISION ONLY

XPA

ATTEMPT TO EXCEED PROGRAM AREA WITH

superseded

for

[symbol name]

An attempt has been made
to access
currently defined program space.
E-20

memory

outside

the

APPENDIX F
COMPILER MESSAGES

fatal
error
and
FORTRAN-IO responds with two levels of messages
warning.
If a
warning message
is
received, the compilation will
continue, hut a fatal error will stop the program from being compiled.
The format of messages is:
?FTNXXX LINE:n text
or
%FTNXXX LINE:n text
where
?
%

FTN
XXX
LINE:: n
text
"

fatal
warning
FORTRAN mnemonic
3-letter mnemonic for the error message
line number where error occurred
explanation of error

Square brackets ([ ]) in this appendix signify variables and
output on the terminal.

are

not

Fatal Errors
Each fatal error in the following list is preceded by ?FTN on the user
terminal
and on listings.
They are presented here in alphabetical
order.
ABD

[symbolname]

HAS ALREADY BEEN DEFINED [definition]

The usage given conflicts with current information about the
symbol.
For
example,
a
symbol defined in an EQUIVALENCE
statement cannot be referenced as a subprogram name.

ATL

ARRAY [name]

TOO LARGE

The total amount of core necessary to accommodate this array
is greater than S12P.
AWN

ARRAY REFERENCE

[name]

HAS WRONG NUMBER OF SUBSCRIPTS

The array was defined to have more or fewer dimensions
the given reference.
BOV

than

STATEMENT TOO LARGE TO CLASSIFY
To determine statement type, some portion of
the
statement
must be examined by the compiler before actual semantic and
syntactic analysis begins.
During this classification the
entire portion of the required statement must fit into the

F-l

COMPILER MESSAGES
internal statement buffer (large enough for a normal 20-line
statement) .
This error message is issued when the portion
·if a <Jivon statement
required for classification is too
large to fit in the buffer. Once FORTRAN-IO has classified
a statement, there is no explicit restriction on its length.
CER

COMPILER ERROR IN ROUTINE [name]
Submit an SPR for any occurrence of this message.

CFF

CANNOT FIND FILE
'[he

file referenced in an INCLUDE statment was not found.

CPE

CHECKSUM OR PARITY
[name]

ERROR

CQL

NO CLOS[NG QUOTE IN

LITE~AL

CSF

ILLEGAL STATEMENT fUNCTION REFERENCE IN CALL STATEMENT

DDA

[symbolname]

OFC

VARIABLE DIMENSION [name] MUST BE SCALAR, DEFINED AS
OR IN COMMON

DFD

DOUBLE [type] NAME ILLEGAL

[sollrce/listing/object]

FILE

IS DUPLICA'rE DUMMY ARGUMENT

Duplicate fields
specification.
DIA

were

encountered

DO INDEX VARIABLE [name]

INCLUDE

file

IS ALREADY ACTIVE

In any nest of DO loops, a given index variable may
defined for more than one loop.
DID

CANNOT INITIALIZE

DLN

OPTIONAL DATA VALUE LIST NOT SUPPORTED

FORMAL

not

DUMMY PARAMETER IN DATA

The extended FORTRAN statement form that allows data
to be defined in type specification statements
supported by FORTRAN-IO.

values
is not

DNL

IMPLIED DO
VARIABLES

DPR

DUMMY PARAMETER [name] REFERENCED BEFORE DEFINITION

DSF

ARGUMENT [name] IS SAME AS FUNCTION NAME

DTI

THE DIMENSIONS OF [arrayname] MUST BE OF THE TYPE INTEGER

DVE

CANNOT USE DUMMY VARIABLE IN EQUIVALENCE

OWL

[source/listing/object] DEVICE [[device]] WRITE LOCKED

ECT

ATTEMPT TO ENTER [symbolnarne]

EDN

EXPRESSION TOO DEEPLY NESTED TO COMPILE

EID

ENTRY STATEMENT ILLEGAL INSIDE A DO LOOP

elM

ENTRY STATEMENT ILLEGAL IN MAIN PROGRAM

SPECIFICATION

F-2

WITHOUT

ASSOCIATED

INTO COMMON TWICE

LIST

COMPILER MESSAGES
ENF

LABEL [number] MUST REFER TO AN EXECUTABLE STATEMENT, NOT
FORMAT

ETF

ENTEH F'/ULURE [filename]

EXB

EQUIVALENCE EXTENDS COMMON BLOCK [name] BACKWARD

rEE

FOUND [symbol] WHEN EXPECTING EITHER [symbol] OR A [syJ:lbol]

Ge n era 1 s y n t a x err 0 r In e s s a q e .
FNE

LABEL [number] MUST REFER TO A
STATEMENT

FWE

FOUND [symbol] WHEN EXPECTING [symbol]

HOE

HARDWARE DEVICI::
[ [device] ]

lAC

ILLEGAL ASCII CHARACTER [character] IN SOURCL

TAL

INCORRECT ARGUMENT TYPE FOR LIBRARY

IBK

ILLEGAL STATEMENT IN BLOCKDATA SUBPROGRAM

ICL

ILLEGAL CHARACTER [character]

ION

DO LOOP AT LINE:

ERROR

[number]

FORMAT,

NOT

EXECUTABLE

[source/l isting/object]

~UNCTION

[name]

IN LABEL FIELD

IS ILLEGALLY NESTED

You are attemping to terminate a DO loop before
one or more loops defined after the given one.
IDS

IMPLICIT DO INDICES MAY NOT BE SUBSCRIPTED

[D'r

I LLEGAL OR MISSPELLED DATA TYPE

IDV

IMPLIED DO INDEX IS NOT A VARIABLE

lED

INCONSISTENT EQUIVALENCE DECLARATION

terminating

The given EQUIVALENCE declaration would cause some
name to refer to more than one physical location.

DEVICI:~

IFD

INCLUDED FILES MUST RESIDE ON DISK

[10

NON-INTEGER IMPLIED DO INDEX

lIP

ILLEGAL IMPLICIT SPECIFICATION PARAMETER

lIS

INCORReCT INCLUDE SWITCH

ILF

ILLEGAL STATEMENT AFTER LOGICAL IF

symbolic

Refer to Section 9.3.2 for restrictions on logical IF object
statemt~nts .
INN

INCLUDE STATEMENTS MAY NOT BE NESTED

IOD

ILLEGAL STATEMENT USED AS OBJECT OF uO

ISO

ILLEGAL SUBSCRI prE EXPRESS ION IN DATA STA'l'Ef1E:J.\lT
Subscript expressions may be formed only
indices and constants combined with +, F-3

with implicit
*, or /.

COMPILER MESSAGES
ISN

[symbolname]

IS NOT

[symbol type]

The symbol cannot be used in the attempted manner.
IUT

PROGRAM UNITS MAY NOT BE TERMINATED WITHIN INCLUDED FILES

IVP

INVALID PPN

IXM

ILLEGAL MIXED MODE ARITHMETIC
Complex and
expression.

IZM

double-precision

cannot

appear

the

same

ILLEGAL [datatype] SIZE MODIFIER [number]
Refer to Section 6.3.

LAD

LABEL [number] ALREADY DEFINED AT LINE:

LED

ILLEGAL LIST DIRECTED [statement type]

LFA

LABEL ARGUMENTS ILLEGAL IN FUNCTION OR ARRAY REFERENCE

LGB

LOWER BOUND GREATER THAN UPPER BOUND FOR ARRAY [name]

LLS

LABEL TOO LARGE OR TOO SMALL

[number]

Labels cannot be 0 or greater than 5 digits.
LNI

LIST DIRECTED I/O WITH NO I/O LIST

LTL

TOO MANY ITEMS IN LIST - REDUCE NUMBER OF ITEMS
In rare instances, a combination of long lists in
statement can exhaust the syntax stack.

MCE

MORE THAN I

MSP

STATEMENT NAME MISSPELLED

MWL

ATTEMPT TO
ARGUMENTS

NCF

NOT ENOUGH CORE FOR FILE SPECS.

NEX

NO EXPONENT AFTER D OR E CONSTANT

NFS

NO FILENAME SPECIFIED

single

COMMON VARIABLE IN EQUIVALENCE GROUP

DEFINE

MULTIPLE

RETURN

WITHOUT

FORMAL

LABEL

TOTAL K NEEDED= [number]

The INCLUDE statement requires a filename.
NIO

NAMELIST DIRECTED I/O WITH I/O LIST

NGS

CANNOT GET SEGMENT [name]

- ERROR CODE:

Refer to Appendix E of the Monitor
description of codes.

Calls

[number]
Manual

NIR

REPEAT COUNT MUST BE AN UNSIGNED INTEGER

NIU

NON-INTEGER UNIT IN I/O STATEMENT

NLF

WRONG NUMBER OF ARGUMENTS FOR LIBRARY FUNCTION

F-4

for

[name]

Eull

COMPILER MESSAGES
NN F

NO S'l'AT Eli EI\)'1' N UMBCR ON FOh:\1AT

NRC

STATEMENT NOT RECOGNIZED

NUO

.NOT.

NWD

INCORRECT USE

OPW

OPEN PARAIv1£TEH [name]

PD6

FORTRAN WILL NOT RUN ON A PDP-6

PIC

THE DO PARAMETERS

PRF

PROTECTION FAILUHL

PTL

PROGRAM TOO LARGE

IS A UNARY

OPER~TOR

or * OR?

[filename]

IS OF WRONG TYPE

or [index name] MUST BE INTEGER CONSTANTS
[fi ll?n3,rne]

The program takes up more than 512P
QEF

QUOTA EXCEEDED OR DISK FULL [filename]

QEX

BLOCK
TOO
LARGe
[source/listing/object]

RDE

RIB OR DIRECTOPY ERROR [filename]

RFC

[funct iOI1 na l"1e]

RIC

COMFLEX CONSTANT CANNOT BE USED TO REPRESENT
IMAGINARY PART OF A COMPLEX CONSTANT

SAD

ARRAY [name] - SIGNED DIMENSIONS MAY APPEAR ONLY AS CONSTANT
RANGE LHlITS

SNL

[statement name]

SOR

SUBSCRIPT OUT OF RANGE

TFL

TOO MANY f'OR:v1AT LABELS SPECIFIED

'rOF

MORE THAN 2 OUTPUT FILES ARE NO'l' ALLOwED

EXCEEDED

OR
QUOTA
rILE [name]

FOR

I S A RECURS IVE FUNCTION CALL
THE

REAL

STATEMENTS MAY NO'l BE LABELED

Only a
listing
and
a
relocatable
specified as output files.
UCE

USER CORE EXCEEDED

UMP

UNMATCHED PARENTHESES

USI

[symbol type]

[symbol name]

binary

file

USED INCORRECTLY

The given symbol cannot be used in this way.
VNA

SUBSCRIPTED VARIABLE IN EQUIVALENCE BUT NOT AN ARRAY

VSE

EQUIVALENCE SUBSCRIPTS MUST BE INTEGER CONSTANTS

VSO

VARIABLE DIMENSION ALLOWED IN SUBPROGRAMS ONLY

F-5

may

COMPILER MESSAGES
Warning Mes;3agos
Each warning message in the following list is preceded by %FTN on
the
user
terminal
and
on
listings.
They are
presented
here
in
alphabetical order.
AGA

OPT - OBJECT VARIABLE, OF
LIST, WAS NEVER ASSIGNED

ASSIGNED

CAl

COMPLEX EXPRESSION USED IN ARITHMETIC

CTR

COMPLEX TERMS USED IN A RELATIONAL OTHER THAN EO OR NE
The result of the other relational
operands is undefined.

CUO

GOTO

WITHOUT

OPTIONAL

operators

with

complex

CONSTANT UNDERFLOW OR OVERFLOW
This message
is
issued
when overflow or
underflow
is
detected
as
the result of building constants or evaluating
constant expessions at compile time.

DIM

POSSIBLE DO INDEX MODIFIED INSIDE LOOP
A program that does this may be incorrectly compiled by
the
optimizer, since it assumes that indices are never modified.
Note that the number of
iterations
is
calculated at
the
beginning
of the loop and is never affected by modification
of the index within the loop.

DIS

OPT -

PROGRAM IS DISCONNECTED - OPTIMIZATION DISCONTINUED

Submit an SPR if this message occurs.
DXB

DATA STATEMENT EXCEEDS BOUNDS OF ARRAY

[name]

FMR

MULTIPLE RETURNS DEFINED IN A FUNCTION

f'NA

A FUNCTION WITHOUT AN ARGUMENT LIST

ICC

ILLEGAL CHARACTER, CONTINUATION FIELD OF INITIAL LINE
Continuation lines cannot follow comment lines.

ICD

INACCESSIBL8

COO~.

STATEMENT DELETED

The optimizer will delete statements that cannot be
during execution.

Ies

ILLEGAL CHARACTER IN LINE SEO#

IDN

OPT -

ILLEGAL DO NESTING -

reached

OPTIMIZATION DISCONTINUED

A GO TO within a DO loop goes to the ending statement of
an
inner, nested DO loop.
The line number printed out with the
warning message is that of the OUTER DO.
DO

GO TO

F-6

COMPILER MESSAGES

CONTINUE

CONTINUE
IFL

OPT -

LID

IDENTIFIER [name] MORE THAN SIX CHARACTERS

INFINITE LOOP.

OPTIMIZATION DISCONTINUED

The remaining characters are ignored.
MVC

NUMBER OF VARIABLES DOES NOT EQUAL THE NUMBERS OF
IN DATA STATEMENT

CONSTANTS

NED

NO END STATEMENT IN PROGRAM

NOD

GLOBAL OPTIMIZATION NOT SUPPORTED WITH /DEBUG - /OPT IGNORED

NOF

NO OUTPUT FILES GIVEN

PPS

PROGRAM STATEMENT PARAMETERS IGNORED
For compatibility purposes.

RDI

ATTEMPT TO REDECLARE IMPLICIT TYP8

SOD

[name]

VAl

[name] ALREADY INITIALIZED

VND

FUNCTION RETURN VALUE IS NEVER DEFINED

VNI

OPT - VARIABLE

STATEMENT OUT OF ORDER

[name]

IS NOT INITIALIZED

The optimizer analysis determined that
the given variable
was never initialized prior to its use in a calculation.
WOP

OPT - WARNING GIVEN IN PHASE 1.
CORRECT

OPTIMIZED CODE MAY

NOT

One or more of the messages issued
prior
to
this message
resulted
from situations
that violate assumptions made~y
the optimizer and thus may cause it to generate code
that
does not execute as desired.
XCR

EXTRANEOUS CARRIAGE RETURN
Carriage return was not immediately preceded or followed
a line termination character.

ZM1~

SIZE MODIFIER [number] TREATED AS

[data type]

Message is issued when one of the data type size
is used that is accepted only for compatibility.

F-j'

modifiers

COMPILER

MESSAG~S

Internal Compiler errors
An internal compiler error is either an attempt by the comuiler or the
monitor
to document an error
inside
the
FORTRAN compiler.
An
occurrence of an internal compiler error signifies that
something
is
wrong with the FORTRAN-IO compiler.
Monitor-detected internal errors are of the form
[message] AT LOCATION [address]

IN PHASE

[segment]

WHILE PROCESSING STATEMENT [line-number]
where

[message] can be one of
ILLEGAL MEMORY REFERENCE
STACK EXHAUSTED
MEMORY PROTECTION VIOLATION

Compiler-detected errors are of the form
?

INTERNAL COMPILER ERROR PROCESSING STATEMENT NUMBER [line-number]

? CALL TO

[routine-name]

FROM

[address]

Submit an SPR if you received an internal con.?iler error.

F-8

APPENDIX C
FORTRAN-IO REALTIME SOFTWARE

This

ap~endix

C.l

INTRODUCTION

explains how to use the FORTRAN-IO realtime software.

PORRTF 1 ibr ar y s ubr ou tine s (LOCE, RTIN IT, CONEC'l',
HTSTR'l',
BLERW,
RTREAD,
RTWRIT,
STATO, STATI, RTSLP, RTWAKE, DISMIS, DISCON, UNLOCK,
and temporary subroutine GETCOR (refer to Section G.3))
are designed
to allow the
timesharing
FORTRAN user to do realtime programming.
With these subroutines, the timesharing job can dynamically connect
realtime devices
to
the
priority interrupt (PI) system, respond to
these devices at interrupt level,
remove
the devices
from
the
PI
system,
and change
their
PI level.
Use of these routines requires
that you have realtime privileges and are able to lock your
job
in
core.
The privilege bits required are:
'Ch,:?

JPORTT
JPOLCK

(BIT 13)
(BIT 14)

- realtime privileges
- locking privileges

The number of realtime devices that can be handled at one time
is an
assembly-ti~e
constant,
RTDEVN,
in
the
FORRTF source.
The
DIGITAL-distributed software has RTDEVN equal
to
2 but
it can be
changed
(up to 6) by editing the statement "RTDEVN==2" in FORRTF.MAC
and reassembling.

The error messayes output by FORRTF can be
in either
full
message
format
or
coded
format.
(Refer to Table G-l.) Use of the code and
format saves
165 words of
run-time core.
If core
is
limited,
reassembly of FORRTF.MAC with the assembly-time constant SHORT changed
from the DIGITAL--distributed 0 (full
format)
to
-1
(coded
format)
accomplishes the core saving.
On multiprocessor systems,
the
realtime
traps apply only to the
processor
specified
by
the
job's CPU specification.
If
the
specification indicates more than one processor, the specification
is
changed to indicate CPUO.
Note that the priority interrupt channel is
only for the indicated cpu.

G-l

FORTRAN-IO REALTIME SOFTWARE
G.2

USING FORRTF

Users of FORTRAN-IO realtime software must consider the fOllowing:

C.2.1

Use of core

Device control in block or single mode

Priority interrupt levels

Masks

Core

The
job being executed must
be
locked
in core with ~he
LOCK
subroutine.
Any data being read into core can only be read into the
low segment and above the protected
job data area
(the
first
140
locations) .
The subroutine BLKRW tests the validity of the locations
specified
to
receive data
in
block-reading
to ensure
that
no
overwritings occur.
However, when in block mode, the block pointer must
be
reset
before
dismissin0 the end-of-block interrupt;
otherwise, all memory could be
overwritten.

G.2.2

Modes

RealtLne jobs can control their devices in one of two ways:
block
mode or
single mode.
In block mode, an entire block of data is read
or written before the user interrupt routine is run, whereas in single
mode,
the
user
interrupt program
is
run every time
the device
interrupts.
There are two types of block mode;
fast block mode and
normal
block mode.
The response time to read a word of data is 6.5
microseconds for fast mode and
14.6 microseconds
for
normal
mode.
(These are the times necessary to completely service the interrupts on
a KIlO processor).
In single mode, the response
time measured
from
the receipt of a realtime device interrupt until the start of the user
control program is 100 microseconds on a KIlO processor.
A device
in
fast
block mode
requires that a PI channel be dedicated entirely to
itself.

G.2.3

Priority Interrupt Levels

Priority interrupt levels 1 through
6 are
legal depending on the
system configuration.
The lower the number of the level, the higher
the priority of that level.
Programs that execute for
a
long
time
should
not be put on high-priority interrupt levels, since they could
cause other
realtime programs on
lower
levels
to
lose
data.
Specification of
the PI level as zero for a particular device causes
the device to be removed from the PI system.

G-2

FORTRAN-IO REALTIME SOFTWARE
G.2.4

Masks

For a description of the bits included
in the
startmsk
and
irltmsk
parameters of
RTSTRT and
the
status word in STATO and STATI, see
Chapters 3 through 8 of the DECsystern-lO System Reference
Manual
and
Appendix C, IN-OUT DEVICE BIT ASSIGNMENTS of that ma~ual.

G.3

SUBROUTINES

Each of
the
15 subroutines associated with
FORTRAN-IO
realtime
software is described briefly in this section.
These subroutines have
been programmed to be compatible with programs written according
to
the
RTTRP:
REAL TIME TRAPPING UUO specifications,
edition 4 of
l2-Feb-73.

G.3.l

LOCK

LOCK locks the job in core and allocates and initializes the
internal
controlling
tables
for
all
realtime devices.
LOCK must be called
before any other of the realtime routines,
except GETCOR
(refer
to
Section G.3.l5), and must be called exactly once.
CALL LOCK

G.3.2

RTINIT

RTINIT initializes the internal tables controlling a realtime
RTINIT must be called for each individual device being used.
CALL RTINIT (unit, dev, pi, trpadr,

device.

intmsk)

unit

realtime device unit number (any number from 1 to
RTDEVN)
This number is not connected in any way with
the
FORTRAN logical unit number.

dev

device code for the realtime device (see Appendix
A,
DEVICE MNEMONICS
in the DECsystem-lO System
Reference Manual DEC-lO-XSRMA-A-D).

priority interrupt level
on which
the
realtime
device is to be run.
Each individual device in fast
block mode must
have a level dedicated to itself.
If the level is
equal to zero, the device will be removed from the
priority
interrupt system altogether.
If it is
necessary to connect one device to several
levels
simultaneously,
a negative value for pi tells the
system not to remove any other occurrences of
the
device
from
any other
(or
the same) PI level.
(Note
that
this counts as
another
realtime
device.)

G-3

FORTRAN-IO REALTIME SOFTWARE

G.3.3

trpadr

address of a FORTRAN entry to which realtime
interrupts are to trap. This can be a FUNCTION or
SUBROUTINE subprogram. Any variables that must be
shared
between the user level code and the
interrupt level routine must be passed by means of
COMMON.
Passing
them
as parameters causes
disastrous results.

intmsk

mask of all interrupting flags for the realtime
device.
This is actually set up by RTSTkT and
should be zero whenever the realtime device is
inactive, i.e., in a call to RTINIT, except in the
case of fast block mode.
In fast block mode,
intmsk ~ust be set to -1.

CONECT

CONECT tells the system to connect a realtime device to the proper PI
level and sets up several elements of the device controlling tables.
Every device must be CONECTed.
CALL CONECT (unit, mode)

G.3.4

unit

realtime device unit number

mode

-2, write a block of data,
fast
interrupt.
-1, write a block of data,
normal
interrupt.
0, interrupt every word
+1, read a block of data,
normal
interrupt.
+2,
read a block of data, fast
interrupt.

(see RTINIT)
'Tlode;

then

mode;

then

mode;

then

mode;

then

RTSTRT

RTSTRT can be used to start a realtime device as well as to stop it
and zero its interrupt mask. A device must be started to be used and
should be stopped before it is disconnected.
CALL RTSTRT (unit, startmsk, intmsk)
unit

realtime device unit number

startmsk -

flags necessary to start the device
(see the
System Reference Manual, Appendix C).
If the
device is being stopped, this parameter should be
zero.

intmsk

mask of all interrupting bits for
the particular
device
(see the System Reference Manual Appendix
C).
If the device IS In fast block mode and being
started, intmsk should equal -1;
if, however, the
device in any mode is being stopped, the parameter
must be O.

G-4

(see RTINIT)

FORTRAN-IO REALTIME SOFTWARE

G.3.S

BLKRW

BLKRW is ~seJ with either of the block modes.
It sets up the size and
starting address of
the data block being handled.
A new count and
starting address must be set up each time the current one runs out.
CALL BLKRW

G. 3.6

(unit, count, blkadr)

unit

realtime device unit number

count

number of words to be read or written

blkadr

array into which the data is to be written or from
which it is to be read.

RT . READ

RTREAD, used with a device in single mode, reads
single word of data.
CALL RTREAD

G. 3. 7

the

device

(unit, datadr)

unit

realtime device unit number

datadr

address of where to store the data read

(see RTINIT)

RT\~RIT

RTWRIT sends a single word of data to
mode.
CALL RTWRIT

G.3.8

from

realtime

device

single

(unit, datadr)

unit

realtime device unit number

(see RTINIT)

datadr

location of the data word to be sent to the device

STATO

the
status
register
of
a
STATO sends the specified status word to
realtime device.
(See Appendix C, In-Out Device Bit Assignments, in
the DECsy~3tern-IO System R~eference Manual, DEC-IO-XSHMA-A--D.)
CALL STATO (unit, statadr)

G.3.9

unit

realtime device unit number

(see RTINIT)

statadr

location of the word of status bits to be sent
the realtime device

STATI

STATI reads the current device status bits into the location specified
fr inspection by the FORTRAN program.
(See Appendix C, UIn-Out Device
Bit: Assiqnments U,
in the
DECsystem-IO System Reference
r-lanual,
DEC-IO-XSRMA-A-D.)

G-S

FORTRAN-IO REALTIME SOFTWARE
CALL STATI
unit
adr

(unit, adr)
realtime device unit number

(see PTINIT)

location into which the device status bits are
read.

G.3.10

RTSLP

RTSLP is called from the timesharing level and causes the FORTRAN
job
to
sleep until
RTWAKE
is called from interrupt level.
The program
goes to sleep for the specified number of seconds (up to 60).
When it
wakes
up,
it checks to see if RTWAKE has been called from interrupt
level.
If RTWAKE has heen called,
RTSLP returns
to
the calling
program, otherwise the job goes back to sleep again.
CALL RTSLP
tin~

G.3.11

(ti~e)

length of sleep time in seconds

RTWAKE

RTWAKE is called at interrupt level to wake up the FORTRAN program.
CALL RTWAKC

G.3.12

DISMIS

The
user
DISMIS dismisses the interrupt currently being processed.
interrupt must be sure
to dismiss
the
interrupt that causes its
execution to begin.
CALL DISMIS

G.3.13

DISCON

level.
All devices
DISCON disconnects a realtime device from its PI
should be disconnected
through calls to
DISCON before the job is
terminated.
CALL DISCON (unit)
unit

G.3.14

realtime device unit number

(see RTINIT)

UNLOCK

UNLOCK unlocks the
job from core.
When execution of
a
job
is
complete,
the
job is automatically unlocked before the return to the
monitor.
The UNLOCK subroutine provides a method
to
unlock a
job
before execution is complete.
Note that all realtime device handling
must be finished before the job is unlocked.
CALL UNLOCK

G-6

FORTRAN-IO REALTIME SOFTWARE
G.3 .. 1S

GETCOR,

A ..Temporar_y

Subr0!:l-,=--i_~~

GETCOR is a routine that allocates a
specified amount of core
for
FOROTS
use.
The design of FOROTS does not allow FORTRAN jobs to be
locked in core due
to
its
run-time
core needs.
Thus,
you must
allocate
an amount of core sufficient to satisfy FOROTS for running
the particular program being executed
through a
GETCOR call.
The
GETCOR call must precede the LOCK call (see G.3.2).
U~fortun~tely,
the only way to determine the core required for
each program
is
by
running
the
job with ever- increasing arguments to GETCOR.
If the
argument is too small, the following error message appears:
?FRSSYS USER PROGRAM REQUESTED MORE CORE THAN IS AVAILABLE
CALL GETCOR (wds)
number of words of storage to be allocated

wds

Table G-l
Error r1e~;sages
Code Format and Full Message Format
- - - _ . _ - _ --_._-------------------_.• _-- -- -- - - - - - - _ .••

Full Message Format

Code FOLl1a t
1

? ILLEGAL UNI'r NUI'13 CR.
TO HANDLE MORE DEVICES,
REASSEMBLE FORKTF WITH A
LARGER
?ERROR COMES FROM THE
SUBROUTINE "subroutine name"
?RTINIT MUST BE CALLED BEFORE

Subroutine in
which message
occurs

"RTDEVN"

CONECT

CONEC'l~

?CONECT MUST BE CALLED BEFORE
RTSTRT OR BLKRW

4
A

A
B
6

A
B

?REAL TIME BLOCK OUT OF BOUNDS
?END OF BLOCK TOO HIGH
[i. e., overwr i te~; some program
or in high segment]
?END OF BLOCK TOO LOW,
i.e., start address less
than 140
?JOB CANNOT BE LOCKED IN
CORE
?JOB NOT PRIVILEGED
?NOT ENOUGH CORE AVAILABLE
FOR LOCKING
?APR ERROR AT INTERRUPT
LEVEL
?PDL OVERFLOW
?ILLEGAL

HE MO RY
REFERENCE

G-7

RTSTR'l', B LK Rw

13LKRW

LOCK

FORTRAN-IO REALTIME SOFTWARE

Table G-I (Cont.)
Error Messages
Code Format and Full Message

Full Message Format

Code Format
7
A
B

C
D
E

0
I

For~at

A
B

?RTTRP ERROR
realtime trap error of the
following sort
?ILLEGAL PI NUMBER
PI channel not available
?TRAP ADDRESS OUT OF BOUNDS
?SYSTEM LIMIT FOR kE~LTIME
DEVICES EXCeEDED
?JOB NOT LOCKED IN CORE OR NOT
PRIVILEGED
?DEVICE ALREADY IN USE BY
ANOTHER JOB
?OCCURRED IN THE DrSCON
ROUTINE
?OCCURRED IN 'I'HE CONECT
ROUTINE
?NOT ENOUGH CORE AVAILABLE
FOR THE CONTROL BLOCKS
?NOT ENOUGH CORE AVAILABLE
FOR THE GETCOR ROUTINE
?FRSSYS USER PROGRAM REQUESTED
MORE CORE THAN IS AVAILABLE

Subroutine in
which message
occurs

DISCON
CONECT

LOCK
GETCOR
GETCOR

~------------------.----------------------------

G-8

APPENDIX H
FOROTS ERROR MESSAGES

Errors detected
categories:

run-time

(SYS)

FOROTS

fall

system errors

open erros
CLOSE

arithmetic
fault
calculations

errors

(APR)

library errors
routines

- errors

generated

data errors

device errors

(OPN)

the

followin~

- errors internal to FOROTS
I/O errors that occur during file OPEN and

(LIB)

(DAT)

into

- errors
by

numeric

FORLIB

library

- errors in data conversion on I/O

(DEV)

I/O hardware errors

APR and LIB errors are usually reported as warnings
and
the. progrd'TI
continues.
The
number
of
APR and LIB errors listed on the user's
terminal can be changed by the FORTRAN Library Subroutine ERRSET.
See
Table
15-3
for
details.
The
I/O errors (SYS, OPN, DAT, and DEV)
either cause messages to be printed on the terminal or can be
trapped
by an error exit argument (ERR=statement label) on OPEN, READ, WRITE,
and CLOSE.
Table H-l qives the text of the messages which can be printed for SYS,
OPN,
DAT,
and
DEV errors.
The included footnotes give additional
information.
Table U-2 gives the text of the messages which
can
be
printecJ for APR and LIB errors.
The FORTRAN Library Subroutine ERRSNS allows you to find out which I/O
error occurred.
When called, ERRSNS returns one or two integer values
that describe the status of
the
last
I/O operation performed
by
FOROTS.
(The second integer value is optional.)
CALL ERRSNS

(I,J)

calls this subroutine.

is the second, optional integer value.

H-l

FOROTS ERROR MESSAGES

Table B-1
FOROTS I/O Error Messages and ERRSNS Returned Values
First
Value

Second
Value

0
0
101
1
243
246
23
312
24
308
25
302

26
311
28
252
254
262
268

29
250
30
237
238
240
242
245
248
249
251
253

Explanation

No error detected
Satisfactory co!nple t ion (no error detected)
Normal end of job ( 1)
Invalid error call
Unidentified entry in FORERR ( 3)
Unidentified entry in FORERR ( 3)
Backspace error
BACKSPACE illegal for device ( 9)
End-of-file during READ
Attempt to READ beyond valid input ( 8)
Invalid record number
LSCW illegal in binary record or
reading
ASCII;
or attempt to read unwritten ASCII
RANDOM ACCESS
unwritten
record or
or
destroyed record number
Direct access not specified
Cannot RANDOM ACCESS a SEQUENIAL file
CLOSE error
DTA directory is
full
(2)
or protection
error
Rename file already exists (2)
No room or quota exceeded (2)
Cannot delete or
rename
a
non-empty
directory (2)
No such file
File was not found
OPEN failure
DUMP mode
RANDOM or
APPEND access not
implemented;
try IMAGE MODE
DIALOG file cannot be opened (3)
Record length missing for RANDOM ACCESS
Too many devices open:
fifteen maximum
Device not available (2)
Illegal ACCESS for device (2)
Illegal MODE or MODE switch (2)
No directory for project, programmer
number (2)
File was being modified (2)

1. Not currently implemented.
2. OPEN errors
251
through
276 map directly onto error
numbers
returned
by the OPEN UUO;
see Appendix E, "Error Codes", in Software
Notebook 4, IIDEC-IO Monitor Calls
ll

•

3. Error cannot currently occur.
8. Occurs when si~ulating mag tape output;
SKIP RECORD and SKIP FILE
are
illegal.
Also occurs when a non-existent file is opened in MODE=
SEQINOUT and the first operation on that file is a READ.
9. Occurs if OPEN output with BACKSPACE is not a mag tape or disk.

B-2

FOROTS ERROR MESSAGES
Table H-l (Cont.)
FOROTS I/O Error Messages and ERRSNS Returned Values
First
Value

Second
Value
255
256
259
265
266
267
269
270
271
272
274
277

3]
315
3 .t.r,

239
39
4 r,

310
244
260

45
241

47
263
59
313
62
301
306
314
63
305

Explanation

Illegal sequence of Monitor Calls (11)
Bad UFD or bad RIB (2)
Device not availabl~ (2)
Partial allocation only (2)
Block not free on allocation (2)
Cannot supersede an existin~ directory (2)
SFD not found (2)
Search list empty (2)
SFD nested too deeply (2)
No CREATE flag for specified UFD (2)
File cannot be updated (2)
LOOKUP ENTER or RENAME error (2)
Mixed access modes
Cannot do SEQUENTIAL ACCESS on a
RANDOM
file
Invalid logical unit number
Illegal FORTRAN unit number (2)
Error during READ
REREAD before first READ is illegal (1)
Device handler not resident
No such device (2)
No such device (2)
OPEN statement keyword error
Switch error
during
DIALOG
or
OPEN
statement scan (2)
Write on read-only fLle
Write-lock error (2)
List-directed I/O syntax error
Illegal delimiter in LIST DIRECTED input
Syntax error in FORMAT
Illegal character in FORMAT statement (4)
I/O list without data conversion in FORMAT
Missing width field for A or R on input
Output conversion error
Optional * fill:
unidentified entry
in
FORERR (7)

----------'---,._----'-----

1. Not currently implemented.
2. OPEN errors
251 through
276 map directly onto error numbers
returned by the OPEN UUO;
see Appendix E, "Error Codes", in Software
Notebook 4, "DEC--IO Monitor Calls".
4.

In runtime FORMAT.

* fill controlled by compile-time variable ASTFIL.

11. Can occur on OPEN (MODE= 'APPEND') when file is found in LIB:
or
on
[1,4]
when device specified was SYS:
and /NEW was in your search
list.

H-3

FOROTS ERROR MESSAGES
Table H-l (Cont.)
FOROTS I/O Error Messages and ERRSNS Returned Values
First
Value

Second
Value

Explanation

~--------------~-----------+---------.---------.------------------------.------------

f)4

303
307
67
304
81
102
261

699
247
257
258
264
273
275
276

799
309
899
400
401
402
403
404
407

999
100
103
104
105
106

Inp~t conversion error
Checksum error reading binary records (5)
Illegal character in data
Record too small for I/O list
I/O list greater than record size (6)
Invalid argument
Argument block not in correct format
Argument block not in correct format (2)
Unclassifiable error on OPEN
FOROTS system error (2,3)
FOROTS system error (2)
FOROTS system error (2)
Not enough monitor table space (2)
FOROTS system error (2)
FOROTS system error (2)
FOROTS system error (2)
Unclassifiable data error
Variable cannot be found in NAMELIST block
Unclassifiable device errors
Write protected
Device error
Parity error
Block too large, quota exceeded,
or
file
structure
full.
Nonexistent
CDR reader.
Spooled CDR file does not exist.
End-of-file (10)
End -0 f -tape
Unclassified system error
FOROTS system error
Monitor not build to support FOROTS
Fatal error
User program has requested more code
than
is available
Run time memory management error

f - - - . - - - - - - - - - - - . L - - - - - -__- - L_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _

.~_~

2. OPEN errors
251
through
276 map directly onto error
numbers
returned
by the OPEN UUO;
see Appendix E, "Error Codes", in Software
Notebook 4, "DEC-IO Monitor Calls".
3. Error cannot currently occur.
5. Checksumming controlled by compile-time variable CHKSUM.
6. Occurs when a type 2 LSCW is found in a FORSE binary record.
10. Trappable if there is no END= clause.
~,-----------------------------------------------------------------------~

H-4

FOROTS ERROR MESSAGES
Table B-2
FOROTS Arithmetic and Library Error Messages
----------------------- -..,----

APR

LIB

In te~re rOve r flow

Attempt to take DLOG of Negative Arg.

Integer Divide Check

Attempt to take DSQRT of Negative Arg.

Illegal APR Trap

ACOS of Arg. > 1.0 in Magnitude

Floating Divide Check

ASIN of Arg. > 1.0 in Magnitude

Floating Underflow

Attempt to take SQRT of Negative Arg.
Attempt to take LOG of Negative Arg.

---------

-~---

-------------.-----

H-5

~--.-

-~-

---- -"- ..

INDEX

.'
A format descriptor, 13-12
ACCEPT, INTRO-S-2
ACCEPT statement, 10-18
ACCEPT transfer,
formatted, 10-18
into FORMAT statement, 10-19
Account number, INTRO-S-2
ACCESS in file control
statement, 12-3
Accumulator usage, C-IO
Accuracy of doubleprecision numbers, C-l
ACOS function, IS-II
Addition, 4-1
Adjustable dimensions, 6-2
ALL with DEBUG, B-3
Allocation,
register, C-7
ALOG function, 15-10
ALOGIO function, lS-10
Alphanumeric data transfer,
13-12
Alphanumeric FORMAT field
descriptor, 13-11
.AND., 4-S
ANSI standard, 1--1
APPEND with ACCESS, 12-4
Arqument,
subprogram, lS-l
Arqument type,
COBOL/FORTRAN, C-12
Arithmetic,
mixed-mode, 4-2
Arithmetic assignment
statement, 8--1
Arithmetic expression, 4-1
Arithmetic IF statement, 9-3
Arithmetic operator, 4-1
Array, 3-7
dimensioning, 3-9, C-4
Array elements,
storage of, 3-10
Array subscript, 3-8
ASCII with MODE, 12-4
ASCIZ string, C-14
ASIN function, 15-11
ASSIGN statement, 8-4
Assigned GOTO statement, 9-2
Assignment statement,
arithmetic, 8-1
label, 8-4
logical, 8-4
mixed-mode, 8-1
ASSOCIATE VARIABLE in file
control statement, 12-8
ATTACH, INTRO-7-3
ATAN function, 15-11
AT.A.N2 function, IS-II
AXIS subroutine, lS-19

BACKFILE statement, 14-3
BACKSPACE statement, 14-2
BASIC,
input from, 2-6
Basic external function
subprogram, lS-8
Beginning a job, INTRO-1-1
BINARY with MODE, 12-4
Blank line, 2-6
BLOCK DATA statement, 16-1
BLOCK SIZE in file control
statement, 12-8
Block data subprogram, 16-1
BOUNDS with DEBUG, B-3
BUFFER COUNT in file control
statement, 12-8

tC, INTRO-l-l
tc monitor call, INTRO-3-3
Call,
FUNCTION, lS-16
subroutine, lS-13
CALL statement, lS-13
Carriage control character,
13-16
Carriage return key, INTRO-1-2
Category,
statement, 1-1
CCOS function, IS-II
CEXP function, lS-10
Changing a line, INTRO-3-4
Changing a program, INTRO-4-1
Changing line numbers, INTRO-4-S
Character code, A-I
Character set, 2-1
Character set \vi th MODE, 12-L!
Characters,
line formatting, 2-2
line termination, 2-2
CLOG function, lS-10
CLOSE, INTRO-S-4
CLOSE statement, 12-1
CLOSE statement summary, 12-10
CONFIRM, INTRO-7-1
COBOL-IO,
interaction with, C-18
COBOL/FORTRAN argument type,
C-12
Command,
COMPILE, B-4
DEBUG, B-4
EXECUTE, B-4
LOAD, B-4
Comment line, 2-S
Common block name, 6-S
COMMON statement, 6-S
COMPIL in FOROTS, D-2

Index-l

INDEX (CONT.)

Compilation control statement,
5-1
COMPILE command, B-4
Compiler commands, B-4
Compiler generated variable,
B-6
Compiler switches, B-1
Compiler version, B-8
Complex constant, 3-3
Complex format, 13-4
COMPLEX statement, 6-3
Computation,
redundant, C-5
reordering, C-3
Computation in DO-loop,
constant, C-6
Computed GOTO statement, 9-2
CONJG function, 15-12
Constant, 3-1
complex, 3-3
double-precision, 3-3
integer, 3-2
label, 3-6
literal, 3-5
logical, 3-5
octal, 3-4
real, 3-2
Constant computation in
DO-loop, C-6
Constant folding, C-7
Constant propagation, C-7
Continuation field,
line, 2-3
Continuation line, 2-4
Continue (G) option after
PAUSE, 9-11
CONTINUE statement, 9-10
Control statement, 9-1
compilation, 5-1
Control Z, 2-1
COS function, 15-11
COSD function, 15-11
COSH function, 15-11
<CR>, INTRO--1-2
CROSSREF switch, B-2
CSIN function, 15-11
CSQRT function, 15-10

D, INTRO-4-3
D (double-precision notation) ,
3-3
D format descriptor, 13-4
.DAT extension, 12-5
Data,
input/output, INTRO-5-l
Data file, I~TRO-5-3
Data files,
FOROTS, D-4

DATA statement, 7-1
Data transfer operations,
10-1
Data type, 3-1
DATAN function, 15-11
DATAN2 function, 15-12
DATE subroutine, 15-19
DCOS function, 15-11
DEBUG command, B-4
Debug line, 2-6
DEBUG switch, B-2, B-3
Debugger,
FORDDT, E-l
Debugger code size, B-4
DECODE statement, 10-22
DEFAULT, B-15
DEFINE FILE subroutine,
15-17
DELETE, INTRO-4-3, INTRO-6-2
DELETE with DISPOSE, 12-5
Deleting a file, INTRO-6-2
Deletinq 9 line, INTRO-4-3
DENSITY in file control
statement, 12-9
Descriptor,
G format, 13-7
Device control statement,
14-1
Device control statement
summary, 14-3
DEVICE in file control statement, 12-2
Device number,
logical, 10-3
DEXP function, 15-10
DIALOG in file control
statement, 12-9
DIMENSION statement, 6-1
Dimensioning,
array in COMMON, 6-7
Dimensioning array, 3-9, C-4
Dimensions,
adjustable, 6-2
DIMENSIONS with DEBUG, B-3
DIR, INTRO-6-l
Directory,
sub-file, 12-6
user file, 12-6
DIRECTORY,
in file control statement,
12-6
Directory file, INTRO-6-l
DISPOSE in file control
statement, 12-5
Division, 4-1
DLOG function, 15-10
DLOG10 function, 15-10
DO statement, 9-5
DO-loop,
constant computation in, C-6
Index-2

INDEX (CONT.)

DO-loop (Cont.),
execution, 9-6
extended range, 9-8
floating-point, C-2
~nplied in I/O list, 10-5
n,ested, 9- 6
parameters, 9-6
permitted transfers, 9-9
range, 9-5
DO-loop iteration, C-2
DO-loop replacement, C-8
DOUBLE PRECISION statement,
6-3
Double-precision constant,
3-3
Double-precision format,
13-4
Double-precision numbers,
accuracy of, C-1
range of, C-l
DSIN function, 15-11
DSQRT function, 15-10
Dummy argument,
subprogram, 15-1
DUMP subroutine, 15-20
DUMP with MODE, 12-4

E, INTRO-2-2, INTRO-4-5
E (exponential notation),
3-2
E format descriptor, 13-4
EDr~, INTRO-4-1
Editing source files, INTRO-4-1
ENCODE statement, 10-22
END J' INTRO·- 4 - 5
END argument in I/O statement,
10-10
END FILE statement, 14-2
END statement, 5-2, 15-7
Ending source input, INTRO-2-2
ENTER in FOROTS, C-18
Entering a program, INTRO-2-1
ENTRY stab~ment, 15-17
EQ, INTRO-4-5
.EQ . , 4-7
EQUIVALENCE statement, 6-7
.EQV., 4-5
ERR argument in I/O statement,
10-10
ERR in file control statement,
12-10
Error,
fatal, B--17
Error processing,
FOROTS, ])-3
Error reporting, B-17
ERRSET subroutine, 15-21
ERRSNS subroutine, 15-21
ESCll~PE,

IN~~RO-2-2

Evaluation of expression,
4-9
EVEN with PARITY, 12-9
EX, INTRO-3-1
Examples,
SOS, INTRO-8-1
Executable statement, 1-1
EXECUTE, INTRO-3-1
EXECUTE command, B-4
Execution,
interrupting, INTRO-3-3
Execution on non-DEC
machines, C-l
Exit (X) option after PAUSE,
9-11
EXIT subroutine, 15-21
EXP function, 15-10
EXPAND switch, B-2
Exponential notation, 3-2
Exponentiation, 4-1
permitted, 4-4
Expression,
arithmetic, 4-1
evaluation of, 4-9
logical, 4-4
mixed-mode, 4-10, 4-11
nested, 4-9
relational, 4-7
Extension,
.SHR, B-18
External function subprogram,
15-7
basic, 15-8
EXTERNAL statement, 6-8

F format descriptor, 13-4
F40 compiled programs, C-18
. FALSE., 3-5
Fatal error, B-17
Field,
label, 2-3
line continuation, 2-3
remarks, 2-4
statement, 2-3
Field descriptor,
alphanumeric FORMAT, 13-11
FORMAT, 13-2
logical FORMAT, 13-10
numeric FORMAT, 13-4
FILE, INTRO-2-1
File,
.FOR, INTRO-2-1
.REL, INTRO-7-1
data, INTRO-5-3
deleting a, INTRO-6-2
directory, INTRO-6-1
directory subfile, 12-6
editing, :NTRO-4-1
Index-·3

INDEX (CONT.)

File (Cont.),
FonOTS data, D-4
non-FORTRAN-IO, C-9
renaming a, INTRO-6-2
source, INTRO-2-1
File control statement, 12-1
File directory,
user, 12-6
FILE in file control
statement, 12-5
FILE SIZE in file control
statement, 12-8
FIND statement, 10-21
Floating-point DO-loop, C-2
Folding,
constant, C,·,7
.FOR extension, INTRO-2-1
FORDDT debugger, E-l
FORDDT messages, E-17
FORMAT field descriptor,
alphanumeric, 13-11
logical, 13-10
numeric, 13-4
record formatting, 13-15
FORMAT statement, 13-1
ACCEPT transfer into, 10-19
transfer into, 10-3
FORMAT statement descriptor,
13-2
Formatted ACCEPT transfer,
10-18
Formatted READ transfer,
random access, 10-13
sequential, 10-11
Formatted WRITE transfer,
random access, 10-17
sequential, 10-16
FOROTS,
using, D-13
FOROTS data files, D-4
FOROTS error processing, D-3
FOROT~ features, D-2
FOROTS hardware requirements,
D-l
FOROTS input/output
facility, D-3
FOROTS messages, H-l
FOROTS software requirements,
D-l
FOROTS/FORSE compatibility,
C-21
FOROTS/LINK interface, D-28
FORSE/FOROTS compatibility,
C-21
FORTRAN-I0 compiler, B-1
FORTRAN-I0 messages, F-l
FUNCTION call, 15-16
Function references,
order, C-8
FUNCTION statement, 15-7

Function subprogram,
basic external, 15-8
external, 15--7
intrinsic, 15-3
statement, 15-3
Function subprogram structure,
15-7
FUNCTION type, 15-7

G (option after PAUSE), 9-11
G format descriptor, 13-4,
13-7
. GE., 4-7
General (G) numeric format,
13-7
GETOVL in LINK, C-20
Global optimization, C-4
GO TO statement, 9-1
assigned, 9-2
computed, 9-2
unconditional, 9-1
GRIPE, INTRO-6-3
. GT., 4-7

H (literal notation), 3-5
H format descriptor, 13-12
Hardware requirements,
FOROTS, D-l
Hierarchy of operators, 4-9
Hollerith literal, 3-5

I, INTRO-4-1
I format descriptor, 13-4
I/O list, 10-5
IF statement, 9-3
arithmetic, 9-3
logical, 9-4
ILL subroutine, 15-21
IMAGE with MODE, 12-4
IMPLICIT statement, 6-5
In I/O list DO-loop,
implied, 10-6
Inaccessible code, C-7
INCLUDE statement, 5-1
INCLUDE switch, B-2
INDEX with DEBUG, B-3
INIOVL in LINK, C-20
Initial line, 2-4
INPUT, INTRO-2-1
Input,
line-sequence, 2-6
Input from BASIC, 2-6
Input from LINED, 2-6
Input/output data, INTRO-5-1
Index-4

INDEX (CONT . )

Input/output facility,
FOROTS, D-3
Input/output list, 10-2
NAMELIS'l', 10-10
Input/output optimization,
C-8
Input/output statement, 10-1
list-directed, 10-8
Input/output statement
format, 10-2
Input/output statement
summary, 10-24
INSERT, INTRO-4-1
Inserting a line, IN~RO-4-1
Integer constant, 3-2
Integer format, 13-4
INTEGER statement, 6-3
Intrinsic function subprogra.m, 15-3
Iteration,
DO-loop, C-2
Interrupting execution,
INTRO-3-3

Job,
beginning a, INTRO-l-l
disconnected (attach),
INTRO-7-3
killing a, INTRO-7-l
number forgotton, INTRO-7-4
JOB number, INTRO-1-2

K (kill file), INTRO-7-1
KAlO switch, B-2
Keyword, 1-1
K/F fast logout, INTRO-7-2
KIlO switch, B-2
Killing a job, INTRO-7-1
KJOB, INTRO-7-l

L format descriptor, 13-10
Label assignment statement, 8-4
Label constant, 3-6
Label field, 2-3
LABELS with DEBUG, B-3
. LE., 4-7
LEG.A.L subroutine, 15-21
Line,
blank, 2-6
comment, 2-5
continuation, 2-4
debug, 2-6
d'2finition, 2-2
fields, 2-2

Line (Cont.),
initial, 2-4
multi-statement, 2-5
Line continuation field,
2-3
Line formatting characters,
2-2
Line sequence number, B-5
LINE subroutine, 15-21
LINE terminal settlng,
INTRO-l-l
Line termination characters,
2-2
Line types, 2-4
Line-sequence input, 2-6
LINED,
input from, 2-6
LINK-IO overlay facility,
C-20
LINK/FOROTS interface, D·-28
List,
input/cutput, 10-2
NAMELIST input/output, 10-10
LIST with DISPOSE, 12-5
List-directed input/output
statement, 10-8
List-directed transfer,
sequential READ, 10-12
sequential WRITE, 10-17
Listing,
program, B-5
Literal constant, 3-5
Literal format conversion,
13-13
LNMAP switch, B-2
LOAD command, B-4
Location in object program,
B-5
Logging in, INTRO-l-l
LOGIN, I:ITRO-1-2
Logical assignment statement,
8-4
Logical constant, 3-5
Logical expression, 4-4
Logical FORMAT field
descriptor, 13-10
Logical IF statement, 9-4
Logical operator, 4-5
LOGICAL statement, 6-3
Logical unit number, 10-3
LOGOVL in ~INK, C-20
. LT., 4-7

MACRO in listing, B-5
MACRO-IO libraries, C-14
MACROCODE switch, B-2

Index-5

INDEX (CONT . )

Messages,
FORDDT, E-17
FOROTS, H-l
FORTRAN-la, F-l
realtime, G-7
Mixed-mode arithmetic, 4-2
Mixed-mode assignment
statement, 8-1
Mixed-mode expression, 4-10,
4-11
MKTBL subroutine, 15-22
MODE in file control
statement, 12-4
MONITOR, INTRO-1-2
Monitor,
calling the, INTRO-3-3
Multi-statement line, 2-5
Multiple record transfer,
13-14
Multiplication, 4-1

N, INTRO-·-4--5
Name,
symbolic, 3-6
NAMELIST input/output list,
10-10
NAMELIST statement, 11-1
NAMELIST-controlled transfer,
input, 11-2
output, 11-3
sequential READ, 10-13
sequential WRITE, 10-17
. NE., 4-7
Nested DO-loop, 9-6
Nested expression, 4-9
NOERRS switch, B-2
NONE with DEBUG, B-3
Nonexecutable statement, 1-1
Non-FORTRAN-IO files, C-9
Non-FORTRAN-IO programs, C-9
NONSHAR, B-18
.NOT., 4-5
NOWARNINGS switch, B-2
NUMBER, INTRO-4-5
NUMBER subroutine, 15-22
Numeric,
field width variable, 13-10
Numeric format,
general (G), 13-7
Numeric FORMAT field
descriptor, 13-4

to, INTRO-6-2
o format descriptor, 13-4
Object program, INTRO-3-l

Object program,
location in, B-5
Octal constant, 3-4
ODD with PARITY, 12-9
OPEN, I~JrrRO-5-3
OPEN statement, 12-1
OPEN statement sUffiQary, 12-10
Operator,
arithmetic, 4-1
hierarchy, 4-9
logical, 4-5
Operator strength, C-5
Optimization,
global, C-4
program, C-9
OPTIMIZE switch, B-2
.OR., 4-5
Order of statements, 2-7
OTS, B-18
Output,
suppressing printed,
INTRO-6-2
Overflow, C-3
Overlay facility,
LINK-lO, C-20

P, INTRO-4-4
P (preserve file), INTRO-7-l
PARAMETER statement, 6-9
PARITY in file control
statement, 12-9
PASSWORD, INTRO-1-2
PATH with DIRECTORY, 12-7
PAUSE statement, 9-11
PDUMP subroutine, 15-22
PLOT subroutine, 15-22
PLOTS subroutine, 15-22
PPN, INTRO-7-3
Precision for real constant, 3-2
PRINT, INTRO-4-4
PRINT statement, 10-19
PRINT with DISPOSE, 12-5
Printed output,
suppressing, INTRO-6-2
printing lines of source,
INTRO-4-4
Program listing, B-5
PROGRAM statement, 5-1
Program,
changing, INTRO-4-l
entering, INTRO-2-l
running, INTRO-3-l
storing, INTRO-2-2
Programs,
non-FORTRAN-lO, C-9
optimizing, C-9
writing, C-l

Index-6

INDEX (CONT . )

Propagation,
constant, C-7
PROTECTION in file control
statement, 12-6
PUNCH statement, 10-20
PUNCH with DISPOSE, 12-5

QUIT, INTRO-4-5

R, INTRO-4-3
R format descriptor, 13-12
. RSOS, IN'rRO- 2-1
RAN funct.ion, 15-12
RANDIN with ACCESS, 12-3
Random access data transfer,
10-1
Random access record
specification, 10-7
Random access transfer,
formatted READ, 10-13
formatted WRITE, 10-17
unformatted READ, 10-13
unformatted WRITE, 10-17
RANDOM with ACCESS, 12-3
Range of double-precision
numbers, C-l
RE1\D, INTRO-5-1
READ statement, 10-11
RE1\D stabement summary,
10-14
RE1\D transfer,
random access, 10-13
sequential, 10-11, 10-12,
10-13
Real constant, 3-2
Real format, 13-4
REAL statement, 6-3
Realtime messages, G-7
Realtime software, G-1
Record formatting (T and X) ,
13-15
RECORD SIZE in file control
statement, 12~8
Record specification,
random access, 10-7
Reentrant program, B-18
Register allocation, C-7
.REL extension, INTRO-7-1
Relational expression, 4-7
RELEAS subroutinE!, 15-23
Remarks field, 2-4
REMOVL in LINK, C-20
RENAME, INTRO-6-2
RENAME with DISPOSE, 12-5
Renaming a file, INTRO-6-2

Repeat for format
descriptor, 13-3
REPLACE, INTRO-4-3
Replacement,
DO-loop, C-8
Replacing a line, INTRO-4-3
Reporting,
error, B-17
REREAD statement, 10-14
RESET in FOROTS, C-IO
Return key,
carriage, INTRO-1-2
RETURN statement, 15-8, 15-14
REWIND statement, 14-1
RUBOUT key, INTRO-2-3
Running a program, INTRO-3-1
RUNOVL in LINK, C-20

S (save file), INTRO-7-1
SAVE with DISPOSE, 12-5
SAVRAN subroutine, 15-23
Scale factor in FORMAT
statement, 13-7
SCALE subroutine, 15-23
SEG, B-18
SEQIN with ACCESS, 12-3
SEQINOU~ with ACCESS, 12-3
SEQOUT with ACCESS, 12-3
Sequence number,
line, B-5
sequential data transfer,
10-1
Sequential transfer,
READ, 10-11, 10-12, 10-13
WRITE, 10-16, 10-17
SET RECORD statement, 14-3
SETABL subroutine, 15-23
SETRAN subroutine, 15-23
SFD, 12-6
Sharable program, B-18
.SHR extension, B-18
SIN function, 15-10
SIND function, 15-11
SINH function, 15-11
SKIP FILE statement, 14-3
SLITE subroutine, 15-23
SLITET subroutine, 15-23
Software requirements,
FOROTS, D-l
SORT subroutine, 15-24
SOS, INTRO-2-1
SOS examples, INTRO-8-1
Source file, INTRO-2-1
Source program, INTRO-2-1
Specification statement,
6-1
SQRT function, 15-10

Index-7

INDEX (CONT . )

SSAVE switch, B-18
SSWTCH subroutine, lS-23
Statement,
ACCEPT, 10-18
Arithmetic assignment,
8-1
arithmetic IF, 9-3
ASSIGN, 8-4
assigned GOTO, 9-2
BACKFILE, 14-3
BACKSPACE, 14-2
BLOCK DATA, 16-1
CALL, lS-13
CLOSE, 12-1
COMMON, 6-S
COMPLEX, 6-3
computed GOTO, 9-2
CONTINUE, 9-10
control, 9-1
DATA, 7-1
DECODE, 10-22
device control, 14-1
DIMENSION, 6-1
DO, 9-S
DOUBLE PRECISION, 6-3
ENCODE, 10-22
END, S-2, lS-7
END FILE, 14-2
ENTRY, lS-17
EQUIVALENCE, 6-7
executable, 1-1
EXTERNAL, 6-8
file control, 12-1
FIND, 10-21
FORMAT, 13-1
FUNCTION, 15-7
GOTO, 9-1
IF, 9-3
IMPLICIT, 6-S
INCLUDE, S-l
input/output, 10-1
INTEGER, 6-3
label assiqnment, 8-4
list-directed,
input/output, 10-8
LOGICAL, 6-3
logical assignment, 8-4
logical IF, 9-4
mixed-mode assignment,
8-1
NAMELIST, 11-1
nonexecutable, 1-1
OPEN, 12--1
PARAMETER, 6-9
PAUSE, 9--11
PRINT, 10-19
PROGRAM, S-l
PUNCH, 10-20
READ, 10--11

Statement (Cont.),
REAL, 6-3
REREAD, 10-14
RETURN, lS-7, lS-14
REl\TIND, 14-1
SET RECORD, 14-3
SKIP FILE, 14-3
STOP, 9-10
SUBROUTINE, lS-9
TYPE, 10-21
type specification, 6-3
unconditional GOTO, 9-1
UNLO}\D, 14-2
WRITE, 10-16
Statement category, 1-1
Statement descriptor,
FORMAT, 13-2
Statement field, 2-3
Statern8nt format,
input/output, 10-2
Statement function
subprogram, lS-3
Statement label constant,
3-6
Statement numbers, 2-3
Statement summary,
CLOSE, 12-10
device control, 14-3
input/output, 10-24
OPEN, 12-10
READ, 10-14
WRITE, 10-18
Statements,
order of, 2-7
STOP statement, 9-10
Storage of array elements,
3-10
Storing a program, INTRO-2-2
Sub-file directory, 12-6
Subprogram,
basic external function,
lS-8
block data, 16-1
external function, lS-7
intrinsic function, lS-3
multiple entries to, lS-17
multiple returns from, lS-14
statement function, lS-3
subroutine, lS-9
Subprogram argument, lS-l
Subprogram dummy argument,
lS-l
Subprograms, lS-l
Subroutine,
DATE, lS-19
ERRSET, lS-21
ERRSNS, lS-21
EXIT, lS-21
FORTR~N supplied, lS-14

Index-8

INDEX (CaNT.)

Subroutine (Cont.),
ILL, 15-21
LEGAL, 15-21
LINE, 15-21
programming consideration,
C-2
Subroutine call, 15-13
SUBROUTINE statement, 15-9
Subroutine structure, 15-13
Subroutine subprogram, 15-9
Subscript,
array, 3-8
Sub~ractionr 4-1
Suppressing printed output,
INTRO-6-2
Swi t.ches,
compiler, B-1
SYMBOL subroutine, 15-24
Symbolic name, 3-6
SYNTAX switch, B-2
SYS, INTRO-7-4

T (trace after PAUSE), 9-12
T format descriptor, 13-15
TAB. INTRO-4-6
TANH function, 15-11
TIM2GO function, 15-12
TIME subroutine, 15-24
Trace (T) option after PAUSE,
9-12
TRACE function, 9-13
TRACE subroutine, 9-13
TRACE with DEBUG, B-3
Transfer operations,
data, 10-1
. TRUE., 3-5
TYPE, INTRO-5-2, INTRO-6-1
Type,
FUNCTION, 15-7
Type specification statement,
6-3
TYPE statement, 10-21

Unconditional GOTO statement,
9-1
Uninitia1ized variable, C-8
UNIT in file control
statement, 12-2
Unit number,
logical, 10-3
Unformatted transfer,
random access,
READ, 10-13
WRITE, 10-17
sequential binary,
READ, 10-12
WRI'l'E, 10-16
UNLOAD statement, 14-2
User file directory, 12-6

Variable, 3-7
compiler generated, B-6
uninitia1ized, C-8
VERSION in file control
statement, 12-8

Warning message, B-17
WHERE subroutine, 15-25
WRITE, INTRO-5-J
WRITE statement, 10-16
WRITE statement summary,
10-18
WRITE transfer,
random access, 10-16, 10-17
sequential, 10-16, 10-17
Writing programs, C-1

X (option after PAUSE), 9-11
X format descriptor, 13-15
. XOR., 4-5

tz, 2-1
tu, INTRO-3-4
UFD " 12-6

Index-9

FORTRAN
Programmer's
Reference Manual
AA-0944E-TB

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