GCC COBOL Compatibility Functions

Purpose

It seems every COBOL compiler includes a library of functions intended to make the COBOL programer's life easier. All of them, as we demonstrate here, can be written in COBOL. They are supplied in COBOL form, not as a library. The user is free to compile them into a utility library.

Some of the functions defined here require runtime support from libgcobol.

Fri Oct 10 16:01:58 2025

At the time of this writing, the functions of greatest concern are those that are defined by Rocket Software (formerly MicroFocus) and emulated by GnuCOBOL. Those are implemented in libgcobol/compat/gnu/lib. Any calls they would otherwise make to the C library are effected through COBOL POSIX bindings supplied by libgcobol/posix/udf/posix-close.cbl.

As an aid to the developer, a simple example of how these functions are used is found in libgcobol/compat/t/smoke.cbl. It may by compiled using libgcobol/compat/t/Makefile.

Thu Nov 13 17:34:43 2025

Naming conventions

• For each POSIX function, we have a COBOL UDF posix-FUNC
• posix/udf/posix-FUNC.cbl defines posix-FUNC
• posix/cpy/psx-FUNC.cpy is a copybook for posix-FUNC
  • the abbreviated prefix prevents conflicts and confusion
  • I'm not sure this is a good idea --jkl
• posix/shim/FUNC.cc provides a C function posix_FUNC (note underscore)
• posix/shim/FUNC.h provides a C version of psx-FUNC.cpy

If posix-FUNC.cbl calls a shim function, it must COPY psx-FUNC to get the required definitions. We ensure the names and values defined in the copybook match those used by the shim.

Status

Of the MF functions, those needed immediately are

Done, not tested:

• CBL_ALLOC_MEM
• CBL_CHECK_FILE_EXISTS
• CBL_DELETE_FILE
• CBL_FREE_MEM

Not written:

• CBL_GET_PROGRAM_INFO (functions 0 + 2)

Tests

We want to write DejaGnu tests that will be activated by

$ make -C gcc check-cobol

Wed Apr 29 15:01:40 2026

The library has been renamed from libcompat to libgcobol_compat_gnu. It is now automatically injected by the gcobol and gcobc front-ends based on the path to the installation prefix.

Tests have been implemented for the following functions:

• CBL_ALLOC_MEM
• CBL_FREE_MEM
• CBL_CHECK_FILE_EXIST
• CBL_CREATE_FILE
• CBL_DELETE_FILE
• CBL_OPEN_FILE
• CBL_CLOSE_FILE
• CBL_WRITE_FILE
• CBL_READ_FILE

cbltypes.cpy and cblproto.cpy can be now COPYed by programs. As of today, cbltypes.cpy only defines the cblt-fileexist-buf data type. On the other hand, cblproto.cpy provides function prototypes for all of the MF functions currently supported by the library.