VMS DECwindows Xlib Routines Reference Manual

This document, published in December 1988, is the first part of the VMS DECwindows Xlib Routines Reference Manual. It serves as a programming guide for experienced developers creating applications with VMS DECwindows, assuming familiarity with VAX calling standards and the C programming language.

The manual details the VMS DECwindows Xlib programming library routines, which provide the programming interface to the X Window System, Version 11. Xlib is described as a subset of the MIT X Window System Release 2 Xlib with several additions, including support for asynchronous programming and VAX Procedure Calling Standard-compliant entry points. It explicitly lists X Version 10 compatibility routines and X extension routines that are not provided in this Xlib implementation.

The document is structured into an introduction and fourteen reference chapters, with Part I covering six routine categories: - Display routines: For connecting/disconnecting to the server, data transfer, and obtaining display information. Examples include OPEN DISPLAY, CLOSE DISPLAY, DEFAULT SCREEN, and various functions to retrieve display properties like DISPLAY HEIGHT MM, BLACK PIXEL, and VENDOR RELEASE. - Window routines: For creating, destroying, mapping, unmapping, configuring, raising, lowering, and querying windows, as well as changing their attributes and translating coordinates. Examples include CREATE WINDOW, MAP WINDOW, DESTROY WINDOW, and SET WINDOW BACKGROUND. - Event routines: For selecting and checking input/output events, handling error conditions, and managing the event queue. Examples include CHECK IF EVENT, MASK EVENT, SEND EVENT, and SET ERROR HANDLER. - Graphics context routines: For creating, manipulating, and changing graphics context structures and attributes. Examples include CREATE GC, CHANGE GC, SET ARC MODE, and SET FILL STYLE. - Graphics routines: For drawing, filling, and erasing points, lines, polygons, arcs, and handling complex images. Examples include DRAW LINE, FILL RECTANGLE, ADD PIXEL, and CREATE IMAGE. - Text routines: For manipulating text within a window, including computing string sizes, returning logical extents, and drawing text. Examples include DRAW STRING, QUERY TEXT EXTENTS, and TEXT WIDTH.

Each routine's documentation follows a standard format, including its VAX and MIT C call formats, an overview, argument descriptions (usage, data type, access, mechanism), return values, and a detailed description of its function and potential X errors. It also describes relevant data structures in both VAX and MIT C bindings.