Compiler Notes

The sample solution consists of two projects:

StressFunctions.f90

The Fortran static library consists of a single module with an Euler buckling method.

This is standard Fortran code. The only extra attribute is the bind(c, name='[name]') statement after the subroutine declaration. This statement forces the internal naming convention to be compatible with C code.

module StressFunctions

    implicit none
    real(8), parameter :: PI = atan(1.0)*4.0

contains
    function EulerBuckling(E, I, L) result(Pcr) bind(c, name="EulerBuckling")

        real(8), intent(in)  :: E, I, L
        real(8) :: Pcr

        Pcr = PI**2 * E*I / (L**2)

    end function

end module

When troubleshooting naming issues, you can verify the function names using "dumpbin /symbols". See DUMPBIN.

dumpbin /symbols StressFunctions.lib

There are two files in the C++ application. The first is a header file, StressFunctions.h, that defines the static library interfaces.

StressFunctions.h

The extern "C" attribute forces the internal naming to be C compatible. By default Fortran passes all arguments by reference. Therefore, all parameters are passed by reference in the C declaration.

#pragma once

extern "C" double EulerBuckling(double* E, double* I, double* L);

Main.cpp

The main function contains the following code. Here we are calling the EulerBuckling method defined in the Fortran static library.

#include <iostream>
#include "StressFunctions.h"
int main()
{
    double E = 10.e6;
    double I = 0.5;
    double L = 15.0;

    double Pcr = EulerBuckling(&E, &I, &L);

    std::cout << "E   = " << E << std::endl;
    std::cout << "I   = " << I << std::endl;
    std::cout << "L   = " << L << std::endl;
    std::cout << "Pcr = " << Pcr << std::endl;
}

Output Directory

To keep the binaries organized, the output and intermediate directory are changed to the following convention. This is helpful because the C++ and Fortran have different output directory defaults.

Output Directory

The same directory convention is applied to the C++ project. The syntax is similar to the Fortran, but it must end in a trailing slash and the macro names are slightly different.

Linker

Here we point the C++ linker to the Fortran LIB file. We take advantage of the output directory structure so that we can define a single syntax for all build scenarios.

Intel Fortran Libraries

In this application we are linking the Microsoft Visual C++ compiler to Intel Fortran. To support this we need to reference the Intel Fortran libraries in the C++ project. See Configuring Visual Studio for Mixed-Language Applications. If you use the Intel C++ compiler, this step is not needed.

Here are some common error messages and strategies for troubleshooting them.

error LNK2019: unresolved external symbol _EulerBuckling referenced in function _main

LINK : fatal error LNK1104: cannot open file 'ifconsol.lib'

LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library