Need help linking c++ function with fortran main in visual studio 2003 .NET

[pal24]

Hi,

Could anybody provide me with a simple walkthrough of how to link a c++ function with a visual fortran main program in visual studio 2003. I'm using Intel Visual fortran 9.0.

I would like to write the following program for example:

Fortran (hello.f):
-------------------
program hello
call helloworld()
stop
end program hello

C++ (helloworld.c):
-------------------
void helloworld()
{
printf("Hello World ");
}

In all my previous attempts, I get the unresolved reference error in when trying to compile the "solution".


Thanks,

[TimP]

Several methods for reconciling them are discussed in the docs files which come with ifort. For example, change to
extern "C" void HELLOWORLD ()
I question whether you want to tackle writing to stdout using C source embedded in a C++ function called from Fortran, if you aren't willing to read about the difficulties.

[pal24]

Hi Tim,

Thanks for the help. I finally got my program working.

[tom_c_lin]

Hi Gentlemen, Good Day,

I have been trying, but unsuccessfully, to link a Fortran main program with C++ library using .NET IDE. This is an'unmanaged' code project(The codes were linked successfully under Intel Fortran command-line). I am really glad to find this message and would like to learn more. Are you using command-line or IDE? If it was .NET IDE. How do you setup the project? one soluction with two inter-dependent projects? How about the project dependencies? Can you share with us your experience on Fortran calling C/C++? Thanks. Your responses are highly appreciated.

Tom Lin

[eric_zhou]

Hi, pal24,

After I tried you helloworld code, error comes out:

error LNK2019: unresolved external symbol _HELLWORLD referenced in function _MAIN

Any changes in project properties

Thanks

Eric

[Jugoslav_Dujic]

_HELLWORLD is missing an "O".

[eric_zhou]

sorry it was _HELLOWORLD

I generated test fortran project "test" than add "hellow.cpp" into the project

All the configrations are default and build the solution was not successed

here is my code:

program test ! test.f90

implicit none

! Variables
call helloworld();

! Body of test

end program test

///// "hellow.cpp""

extern "C" void helloworld();
void helloworld()
{
printf("hello world ");

}

/////build output

------ Rebuild All started: Project: test, Configuration: Debug Win32 ------

Deleting intermediate files and output files for project 'test', configuration 'Debug|Win32'.
Compiling with Intel Fortran 9.0...
test.f90
Linking...
test.obj : error LNK2019: unresolved external symbol _HELLOWORLD referenced in function _MAIN__
Debug/test.exe : fatal error LNK1120: 1 unresolved externals

Build log written to "file://C:Documents and SettingsEricMy Documents estDebugBuildLog.txt"
test build failed.

---------------------- Done ----------------------

Rebuild All: 0 succeeded, 1 failed, 0 skipped

It seems to me that it doesn't compile the c file (hellow.cpp).

any thought please, thanks

Eric

[tom_c_lin]

I finally got my 'Fortran-call-C++' project working. Here is what I did.

1. create a Fortran main project

2. add a C++ project inside the Fortran project

(I select static library in application settings)

3. use add item (in C++ project) to enter C++ code.

4. enter Fortran code in Fortran main project

5. right click Fortran project, select project dependencies,

check the box of the C++code (name). Make sure that the Fortran is

depending on C++ code (Build Order should be C++ code then Fortran)

6. select the same runtime library for both C++ and Fortran

(I used Debug Single-threaded)

7. In the 'additional dependency' of the Fortran add your C++ library name

8. remember in C++, your need to use 'extern "C" ' instead of 'extern'.

Hope this will help. Good luck.

Tom Lin

[eric_zhou]

I did it exactly same.

error comes out: cannot open "ctest.lib"

When I add new c++ project, I choose win32 (console) project with static lib

and then add a hellow.cpp file into c++ project.

Do we need main() in c++ project?

Eric

[tom_c_lin]

For my project, C++ consists of only routines (so called subroutines in Fortran). I don't think you need a C++ main program. My main programis a Fortran which calls C++ routines. I did see the same error message before, i.e., can't open Csub.lib. Whatyou can do is 'add the directory of you C++ library'before you C++ library name (in the additional dependencies of your Fortran project) or copy your C++ library manually toyour Fortran project directory.You need to make sure that your Fortran program 'sees' the C++ library. Good luck.

Tom Lin

[eric_zhou]

Tom,

Thanks a lot

Mine is working now.

Eric