How to code C++ function to call different Fortran function (more than 1)?

[wisperless]

I've been trying to call different Fortran functions from C++. But it looks to me, the C++ functioncompiled byVC++2005can only call 1Fortran function(IVF 9.1). For example, if a Fortran file (f1.f90) has two Fortran functions ( F1, F2)

subroutine F1()

end subroutine

subroutine F2()

end subroutine

I am wondering, from the C++ function, how to call that two functions(F1 and F2). The following code is not working

void F1();

void F2();

int main()

{

F1();

F2();

}

Thank you in advance!

[hajek]

In a C++ program you should add extern "C" to the declarations, otherwise name-mangling may take place. Also, IIRC, Intel (as well as most other compilers) adds an underscore to Fortran names, thus you should declare the subs as

extern "C" void F1_();

...

[wisperless]

Thanks for your pointing out the missed extern "C". I did have that in my computer. I guess my problem is how to call a Fortran subroutine in module from visual C++. I can not even access a variable in the module. Here is my code.

Visual C++:

#include "stdafx.h"
#ifdef __cplusplus
extern "C" 
#endif
extern "C" int EXAMP_mp_A;
int main()
{
printf("test_mp_a %5.1f",EXAMP_mp_A);return 0;
}

Here is my fortran code:
module EXAMP
INTEGER A
!DEC$ ATTRIBUTES DLLEXPORT::EXAMP
contains
subroutine MODFUN! Expose subroutine MODFUN to users of this DLL!write(*,*) "Call from fortran"! Variables! Body of MODFUN
end subroutine MODFUN
end module EXAMP
The compiling error is 
C_CALL_MOD.obj : error LNK2001: unresolved external symbol _EXAMP_mp_A
Anyone can help me out?
Thank you in advance!!

[wisperless]

Ok, I think I solve the problem after adding A

!DEC$ ATTRIBUTES DLLEXPORT::MODFUN

[hajek]

I'm a little confused - I thought you were using static library. Anyway, the DLLEXPORT attribute for a module name has no effect (though it's allowed).

It is somewhat more portable to export only stand-alone subprograms, not module procedures - this way you avoid the name mangling (which is probably fixed forever by Intel compilers, but may differ with other compilers).

Alas, if you want to do the same for variables, you have to resort to the old ugly common blocks. Or wait for the C interop stuff.

By the way, the double extern "C" you specify in your C++ header is redundant. The one specified within the #ifdef block suffices.

[wisperless]

Thank you for your help. I changed to DLL and that's the reason why I added the export. Sorry for the confusion.