Linking Fortran into C

[stevet96]

I have a library that uses both C and Fortran code. I used to be able to build them together in the same project, however Visual Studio .Net 2003 does not allow this. I have created a separate project for both the C and Fortran codes. I have over 100 source files for both Fortran and C. Am I supposed to list every .obj file for all the fortran files if I use the C compiler to link? Is there a better way than to list every .obj file? I built the Fortran codeas a library and linked the library in with the C, but then I get redefinition warnings for every one of my Fortran functions. I have added a few of the Fortran .obj files to the C linker and I receive no redefinition errors. The "Mixed-Language" portion of the programming guide only says to include the .obj files, I'm just wondering if there is an easier way?

Thanks in advance,

Steve

[tongru_huo]

Steve,

I am working on the same problem right now.

The way I do it is that I create a library for the fortran routines.

Then I link the C/C++ routines with the fortran library.

This way always works with CVF6.0 and VC++ 6.0 for me.

You can refer the following article to resolve the multiple redefinition of symbals.

http://h18000.www1.hp.com/fortran/visual/vfn10/page2.html

Another thing you need to do is that you need to put dfor.lib (or dformt.lib for

multi-thread) at the beginging of other C libs. In VS.net, you do this in

project properties page / link /input.

I hope the above process work for you.

I followed the above process, I did have a clean compile and link in VS.net.

But the executable I got was not able to run. The running always exits with

code 255 (0xff). I don't know why. I posted my question in "How to make

CVF 6.0 and MS.net work together".

Regards

Tony

[stevet96]

I don't have a problem with the fortran libraries that need to be added at linking time. What happens is I have a fortran function called DFWITR and Icall that function from C as DFWITR. When I link, the library has the definition for DFWITR in it, but Ialso have DFWITR prototyped for C which cause a redefinition warning. This only happens when I link the Fortran library in. However if I link in the .obj file that contains DFWITR, I don't get the function redefinition warning message.

On a side note,how can I link in dfor.lib before the default C libraries in Visual Studio .NET 2003? The default libraries are not listed. The only possibility I see is to not include all default libraries and list them individually. Am I missing something or did it become harder to order the libraries being linked in, in VS .Net 2003?

[tongru_huo]

The prototype declaration in C should not cause a redefinition of function,

since a prototype is not a function defintion. C/C++ is quite clear about this

point.

The way you declare the fortran function prototype in C/C++ is as follows,

#if defined(cpp)

extern "C" {

endif

return_type dfwrit(argument_list);

#if defined(cpp)

}

endif

Be careful with the different convention of argument list in C/C++ and fortran and the return type, and function name.

As an example, if the fortran routine is as follows,

subroutine F77(d1,d2)

double precision d1, d2

C blah blah

return

end

Then the C prototype should be

void F77(double *d1, double *d2);

This should not cause redefinition of functions in C link for sure.

To put dfor.lib in the front of other c libs will guarantee that the fortran libs

is searched first to resolve symbols. You can do this in project setttings.

Tony