linking dilemma (undefined reference) between MinGW and MSVC. MinGW fails MSVC works

Question

I\'m trying to port an old C .dll library originally done with MSVC that uses BEA Tuxedo library to use MinGW.

I have encountered a situation where MSVC compiles an

Answer 1

As you have already discovered yourself - name mangling may be different across compilers. To solve your problem follow the instructions:

1. Download and install (can build from source) gendef utility:

   • If you have usual MinGW (targeting 32-bit), then obtain it here;
   • If you have MinGW-w64 (targeting 64-bit), then obtain it here.

2. Run gendef wtuxws32.dll (will generate wtuxws32.def);

3. Run dlltool -D wtuxws32.dll -d wtuxws32.def -l libwtuxws32.a (will generate libwtuxws32.a);

4. Put libwtuxws32.a to D:/dev/tuxedo/lib;

5. Now link against it.

Answer 2

Change the declaration of tpsetunsol() in the atmi.h header from:

extern void (_TMDLLENTRY * _TMDLLENTRY tpsetunsol _((void (_TMDLLENTRY *)(char _TM_FAR *, long, long)))) _((char _TM_FAR *, long, long));

to:

extern  void (_TMDLLENTRY * (_TMDLLENTRY tpsetunsol) _((void (_TMDLLENTRY *)(char _TM_FAR *, long, long)))) _((char _TM_FAR *, long, long));
//                          ^                      ^

so the function will be properly declared to be a stdcall function as it is in the library (as indicated by the @4 suffix on the name in the library).