VAX-11 Guide to Creating Modular Library Procedures

This document, the "VAX-11 Guide to Creating Modular Library Procedures" (Order No. AA-H500B-TE, April 1980), is a tutorial for advanced system and application programmers working with VAX/VMS V2.0.

Its primary purpose is to define and guide the implementation of a "modular programming standard" for procedures written in VAX-11 MACRO, BLISS-32, BASIC, FORTRAN, and PASCAL. Adhering to this standard ensures that procedures can be successfully linked, promoting reliability, reducing development time, and easing maintenance, whether used for general programming or inclusion in system/user-created object module libraries or sharable images.

The guide covers:

1. Introduction to Modular Programming and Libraries: Explaining the concepts of modularity, the benefits of library procedures (object module vs. sharable images), and how programs link to them.
2. Designing Procedure Interfaces: Detailing how to define explicit and implicit parameters, establish naming conventions for procedures and facilities, handle errors and condition values, and document procedures.
3. Storage Management: Discussing different types of storage (static, stack, heap) and principles for their use to maintain modularity.
4. Coding Techniques: Providing structured programming recommendations, specific coding rules (e.g., file names, PSECTs), methods for procedure initialization, resource allocation, passing string parameters, and appropriate use of VAX/VMS system services.
5. Asynchronous System Trap (AST) Reentrancy: Guidelines for writing AST-reentrant procedures and techniques to eliminate race conditions in concurrent access scenarios.
6. Building and Modifying Libraries: Instructions on adding procedures to default system libraries, creating user-defined object module libraries and sharable images, and implementing transfer vectors for forward compatibility.
7. The Modular Programming Standard: A comprehensive appendix outlining all required, optional, and recommended rules and principles, along with detailed naming conventions and parameter notation.

The document aims to enable programmers to create reusable and robust software components compatible with the VAX/VMS environment.