Chapter 19: Intrinsic Functions Reference -- Further Reading

Books

"Murach's Mainframe COBOL" by Mike Murach and Associates Murach's text integrates intrinsic functions throughout its chapters rather than isolating them in a single reference section, which helps readers see how functions are used in realistic program contexts. The coverage of CURRENT-DATE for timestamp generation, UPPER-CASE/LOWER-CASE for data normalization, and the numeric functions in COMPUTE statements is particularly well-presented with before-and-after code comparisons. Available from the Murach website and major technical booksellers.

"COBOL Unleashed" by Jon Wessler Wessler's comprehensive reference dedicates an entire chapter to intrinsic functions with detailed tables showing each function's argument types, return types, and edge-case behaviors. The treatment of date functions is especially thorough, covering calendar arithmetic patterns that handle month-end boundaries, leap years, and fiscal calendar conversions. Available through major online booksellers and some technical libraries.

"Beginning COBOL for Programmers" by Michael Coughlan Coughlan's introductory text provides an accessible entry point to intrinsic functions for programmers coming from other languages. He draws explicit parallels between COBOL intrinsic functions and their equivalents in Python, Java, and C, which helps programmers new to COBOL leverage existing knowledge. The exercises progressively build function usage from simple to complex. Available from Apress and major technical booksellers.

Online Resources

IBM Enterprise COBOL Language Reference -- Intrinsic Functions The authoritative reference for every intrinsic function supported by Enterprise COBOL for z/OS. Each function entry includes a syntax diagram, argument type requirements, return type specifications, and behavioral notes for edge cases such as zero-length strings or out-of-range numeric values. Search for "Enterprise COBOL Language Reference" on the IBM Documentation website and navigate to the Intrinsic Functions section.

IBM Enterprise COBOL Programming Guide -- Using Intrinsic Functions The programming guide complements the language reference with practical examples showing how to embed intrinsic functions in MOVE, COMPUTE, IF, and STRING statements. It includes performance considerations for functions called within tight loops and guidance on when a function call is preferable to equivalent procedural code. Find this in the IBM Documentation portal under the Enterprise COBOL Programming Guide.

GnuCOBOL Programmer's Guide -- Built-In Functions The GnuCOBOL documentation provides a complete list of supported intrinsic functions with notes on compatibility with the ISO standard and IBM Enterprise COBOL. Functions that behave differently under GnuCOBOL are flagged with explanatory notes. This is essential reading for developers targeting open-source COBOL compilers. Available through the GnuCOBOL project documentation on SourceForge.

COBOL Standard Intrinsic Function Summary -- NIST COBOL Test Suite The National Institute of Standards and Technology maintained a COBOL validation test suite that includes tests for every standard intrinsic function. Reviewing these test cases provides precise examples of expected input/output behavior, including boundary conditions and error scenarios. The test suite is archived and accessible through government technology archives.

IBM Documentation

IBM Redbook: "Enterprise COBOL Version 6 -- What's New" This Redbook documents functions added or enhanced in recent Enterprise COBOL releases, including UTF-8 support in string functions and extended precision in numeric functions. Understanding version-specific capabilities helps developers take advantage of newer function features when their shop upgrades compilers. Search for this title on the IBM Redbooks website.

IBM Developer Articles on COBOL Date Handling IBM Developer has published several articles specifically focused on date arithmetic using INTEGER-OF-DATE, DATE-OF-INTEGER, and related functions. These articles address real-world scenarios such as calculating business days between dates, determining day-of-week, and handling century boundaries. Search for "COBOL date functions" on the IBM Developer website.

Standards and Specifications

ISO/IEC 1989:2023 -- COBOL Standard, Intrinsic Functions The current COBOL standard contains the formal specification for all standard intrinsic functions, including argument constraints, return type rules, and required precision for numeric results. The standard distinguishes between functions that all conforming compilers must support and those that are optional, which is important for portability planning. Available for purchase through ISO or national standards bodies.

"COBOL-2002 Intrinsic Functions Addendum" -- Historical Reference The COBOL-2002 standard significantly expanded the set of intrinsic functions beyond what COBOL-85 introduced. Understanding which functions were added in which standard revision helps when working with legacy compilers that may not support the full modern function set. Available through standards archives and technical libraries.