FORTRAN Compatibility Guide

This document is the "FORTRAN Compatibility Guide," published by Digital Equipment Corporation in May 1988 (Order Number: EJ-31491-41).

Its primary purpose is to provide reference information for programmers on compatibility issues encountered when transporting FORTRAN programs between different compilers and systems.

The guide specifically addresses compatibility between:

• FORTRAN IV (Version 2.6)
• FORTRAN-77 (Version 5.2)
• VAX FORTRAN (Version 4.7)

It covers these compilers as they run on PRO, PDP-11, and VAX systems.

The document is structured into two main chapters:

1. Introduction: Discusses the relationship of various FORTRAN implementations to different FORTRAN standards (e.g., ANSI X3.9-1978, ISO 1539-1980 (E), ANSI X3.9-1966) and their extensions. It also describes program development tools and methods on PRO, PDP-11, and VAX systems, including available text editors.
2. Language Compatibility Issues: Provides detailed information on FORTRAN language features that cause transportability problems across different systems. This includes incompatibilities related to compiler qualifiers and switches, statements, subroutines, functions, data definitions, expressions, character sets, and system dependencies like I/O differences, file naming conventions, record management services, and error handling.