How to use BOINC with FORTRAN and Visual Developer Studio

2004-06-16 note: this page is outdated (functions are now declared extern"C" so no C++ mangling is done; there is a boinc_api_fortran.C wrapper)

Note: a working example similar to the following (based on outdated BOINC code) is here; see also its README.

Start by creating a new FORTRAN project. Add all the FORTRAN specific files, then add all the files needed for the BOINC library (e.g. boinc_api.C). Make sure that BOINC and the FORTRAN files are compiled using the same type of standard libraries. i.e. if the BOINC is compiled with the debug multithreaded DLL libraries, make sure the FORTRAN files are compiled with the DLL setting.

For every BOINC function you want to call from fortran you must add an interface and subroutine:

INTERFACE
  SUBROUTINE boinc_finish(status)
  END SUBROUTINE boinc_finish
END INTERFACE

Remember to declare the type of arguments. INTEGER status

You must then tell the compiler that the function you are interfacing is a C routine. You do this by adding the statement:

 !DEC$ ATTRIBUTES C :: boinc_finish

Because BOINC is compiled as C++ files the FORTRAN compiler will not be able to find the standard function name in the object file, you therefore have to add an alias for the function giving the real function name:

 !DEC$ ATTRIBUTES ALIAS : '?boinc_finish@@YAHH@Z' :: boinc__finish

This function name can be found in the object file. Go to your compile directory and run dumpbin.

c:\fortranproject\Release>dumpbin /symbols boinc_api.obj

this will give you a list of symbols, where you can find the real functionname.

The interface will end up looking like this:

INTERFACE
  SUBROUTINE boinc_finish(status)
    !DEC$ ATTRIBUTES C :: boinc_finish
    !DEC$ ATTRIBUTES ALIAS : '?boinc_finish@@YAHH@Z' :: boinc__finish
    INTEGER status
  END SUBROUTINE boinc_finish
END INTERFACE

You can now call the BOINC function in FORTRAN.

call boinc_finish(0)