CODEWITHSUNDEEP
c++fortranfortran-iso-c-binding
Mortezanamvar
Mortezanamvar

Reputation: 69

how to mix fortran and C++ in visual studio 2010?

I am trying to call the c++ function from Fortran main program. to do that I followed the bellow steps in visual Studio 2010: To create a C++ static library project

  1. On the menu bar, choose File, New, Project.
  2. In the left pane of the New Project dialog box, expand Installed, Templates, Visual C++, and then select Win32.
  3. In the center pane, select Win32 Console Application.
  4. Specify a name for the project—for example, MathFuncsLib—in the Name box. Specify a name for the solution—for example, StaticLibrary—in theSolution Name box. Choose the OK button.
  5. On the Overview page of the Win32 Application Wizard dialog box, choose the Next button.
  6. On the Application Settings page, under Application type, select Static library.
  7. On the Application Settings page, under Additional options, clear the Precompiled header check box.
  8. Choose the Finish button to create the project.

To create a executable Fortran project

  1. On the menu bar, choose File, New, Project.
  2. In the left pane of the New Project dialog box, expand Installed, Templates, Intel(R) Visual Fortran , and then select Console Application.
  3. In the center pane, select Empty Project.
  4. Specify a name for the project and then Specify a name for the solution. In the solution box select the "Add to solution". Choose the OK button.

In addition I do some setting in Visual studio as below:

  1. Right-click the executable Fortran project and select Dependencies to set the executable project as dependent on the static library project.
  2. Right-click on the executable project and select Set as Startup Project so that you can build it and debug. I have the below Fortran main program and C++ function.

Fortran program

    program main

      use iso_c_binding, only : C_CHAR, C_NULL_CHAR

      implicit none

      interface
        subroutine print_C ( string ) bind ( C, name = "print_C" )
          use iso_c_binding, only : C_CHAR
          character ( kind = C_CHAR ) :: string ( * )
        end subroutine print_C
      end interface

      call print_C ( C_CHAR_"Hello World!" // C_NULL_CHAR )

    end

C++ Function

# include <stdlib.h>
# include <stdio.h>

extern "C" void print_C (char *text)
{
  printf("%s\n", text);
}

When I build the program I will confront to the following errors:

Error 1: error LNK2019: unresolved external symbol _print_C referenced in function _MAIN__  Fortranmain.obj 
Error 2: fatal error LNK1120: 1 unresolved externals    Debug\Fortranmain.exe

Could anyone help me? Any suggestion would be highly appreciate.

Upvotes: 3

Views: 1915

Answers (1)

Peter Petrik
Peter Petrik

Reputation: 10195

You need to link C++ library to Fortran executable. Dependencies are specifying the build order.

  1. Right-click the executable Fortran project and select Properties
  2. Add directory containing build C++ library to Configuration Properties -> Linker - General -> Additional Library Directories (This step is maybe not needed)
  3. Add C++ library .lib file to Configuration Properties -> Linker -> Input -> Additional Dependancies

Upvotes: 2

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