Passing scalar type by value from C# to Fortran

If the Fortran function or routine wants to receive a scalar type by value the argument should be passed by value of equivalent type in C#.

Fortran subroutine

subroutine TestValProc(IntParm )

!DEC$ ATTRIBUTES DLLEXPORT :: TestValProc

!DEC$ ATTRIBUTES VALUE :: IntParm

integer, intent(in) :: IntParm

end subroutine

C# method prototype

        [DllImport("FDLL.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]

        public static extern void TESTVALPROC(int IntParm);

Passing scalar type by reference from C# to Fortran

If the Fortran function or routine wants to receive a scalar type by reference the argument should be passed by reference of equivalent type in C#. By default, Fortran passes all scalar data type by reference so this is the most commonly case.

Fortran subroutine

subroutine TestRefProc(IntParm )

!DEC$ ATTRIBUTES DLLEXPORT :: TestRefProc

integer, intent(inout) :: IntParm

end subroutine

C# method prototype

        [DllImport("FDLL.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]

        public static extern void TESTREFPROC(ref int IntParm);