Call a C++ function from a Fortran module

[wisperless]

I am wonderingthat calling a C++ function from a Fortran subroutine is the same way ascalling from a Fortran subroutine which inside a module?

C++ code

extern

"C" void FORTRAN_CALL_C (int *i,int*j)

{

*i=1;

*j=5;

printf("This is Called from Fortran!
");

}

Fortran Code 1 (calling from a subroutine)

subroutine F1(INT_ARG, STR_IN, STR_OUT)

CALL FORTRAN_CALL_C(INT_ARG, STR_IN)

end subroutine

F1

Fortran code 2 (calling from a module)

MODULE FDLL 

contains

subroutine F1(INT_ARG, STR_IN, STR_OUT)

   CALL FORTRAN_CALL_C(INT_ARG, STR_IN)

end subroutine

F1

I got a message error showing

2>FDLL .obj : error LNK2019: unresolved external symbol FORTRAN_CALL_C referenced in function FDLL_mp_F1

Thank you in advance!

[wisperless]

I forgot to mention that the Fortran code is inside a DLL which is called from another C++ function.

[Steven_L_Intel1]

I don't see anything wrong from what you have posted here. You should make sure that the object file from the C compilation is being linked in with the DLL. There is no difference in how a C routine is called from within a module or not within a module.

[wisperless]

Steve, Thanks you. After I added an interface in the top of the module section, the code works. My another problem is how to define dynamic allocated array in the interface.

module

EXAMP

INTERFACE

SUBROUTINE FORTRAN_CALL_C(INT_array, INT_array2)

!DEC$ ATTRIBUTES REFERENCE :: INT_array, INT_arry2

INTEGER INT_array, INT_arry2 ===> How to define a dynamic allocated array here???

END SUBROUTINE

END INTERFACE

.....

end module.

Since in the Fortran I have an dynamic allocated array that 

pass to C++ function.

Inside the fortran code:

integer noofindex

noofindex=10

allocate(INT_array(noofindex),stat=error)if(error.ne.0) thenwrite(911,*) "allocate INT_array error"stopendif
INT_array(:) = 0

Thank you very much!

[Steven_L_Intel1]

That depends on what the C code does. If it just receives a pointer to the array and uses [] notation to index it, then use DIMENSION(*) in the Fortran interface. If the C code understands Fortran array descriptors and uses the descriptor fields (unlikely), then use DIMENSION(:).

[wisperless]

Thank you very much! My code works now.