[Tiny-cobol-users] How to call a OpenCOBOL DLL module from CSharp

[David E. <de...@us...>]

There are two ways to incorporate TC code with .NET.

One is to use managed code by wrapping the OC C code, and run-time, into
a COM object.

The other is to call TC modules (DLL) directly as unmanaged code.

While more risky, the second approach offers the ability to leverage the
legacy code business logic, and add a winGUI interface.

The following simple examples are presented as a proof of concept only.

The sources were tested using Mono v2 (Linux-32) and CSharp v2 / Mingw
(winXP-32).

To build extract 'readme.txt' file, and follow instructions.

Example:
mono:

  >make
htcobol -v -m cobshlib06.cob -o libcobshlib06.so
gmcs /debug /out:program03.exe program03.cs
...

  >mono program03.exe
program03: cobfunc_dll called
-----------------------------
cobfunc_dll: enter
an_int=42
count_int=10:   0  1  2  3  4  5  6  7  8  9
cobfunc_dll: exit
-----------------------------
program03: cobfunc_dll return
Return Value: 84
str: String filled in DLL


In CSharp, most types are allocated dynamically.
And since COBOL has limited pointer manipulation, some issues wiere
encountered with
C structures with dynamic memory allocation.

Cheers,

References:
1) Calling a DLL with C# (C Sharp)
http://www.adp-gmbh.ch/csharp/call_dll.html