Intel® Software Network

In C# I use StringBuilder to exchange strings with Fortran.

Here are two examples to get and put a character*4 value:

C#

	public static void putusername(string value)
	{
		StringBuilder stringBuilderValue = new StringBuilder(value.Substring(0, System.Math.Min(value.Length, 4)));
		PUT_USERNAME(stringBuilderValue, 4);
	}

	public static string getusername()
	{
		StringBuilder stringBuilderValue = new StringBuilder(4);
		GET_USERNAME(stringBuilderValue, 4);
		return stringBuilderValue.ToString();
	}

Fortran:

	subroutine put_dateiname(value)
		use globaleVariablen
		implicit none
		character*255 dateiname
		dateiname = value
	end subroutine put_dateiname
!
	subroutine put_username(value)
		use globaleVariablen
		implicit none
		character*4 username
		username = value
	end subroutine put_username

Why can´t I edit my post?

Here is the Fortran part again:

	subroutine put_dateiname(value)
		use globaleVariablen
		implicit none
		character*255 dateiname
		dateiname = value
	end subroutine put_dateiname
!
	subroutine put_username(value)
		use globaleVariablen
		implicit none
		character*4 username
		username = value
	end subroutine put_username

Markus

Damn, I posted the wrong Fortran code... It´s too early in the morning and I haven´t had any coffee yet ;-)

globaleVariablen is a module where username is declared as character*4. In the C# part you have to name the length of the character, so you write get_username(stringBuilderValue, 4), although the Fortran function doesn´t have a second parameter. 

 

 

	subroutine put_username(value)
		use globaleVariablen
		implicit none
		character*4 username
		username = value
	end subroutine put_username
!
	character*4 function get_username()
		use globaleVariablen
		implicit none
		getusername = username
	end function get_username

Markus

If you are sending strings to a program written with any type of 'C'- language, do you not have to terminate each string with the null (CHAR(0)) character first? That's how C knows where the string ends. Any string length argument returned by Fortran must therefore include the terminating null character in the count so the C-side string length must match or exceed this length.

Also, whenever a 'C'-type program sends a reference to a string, the string will be terminated with a null character too, so looking for the null character lets you find the string's length.

Ops, and now this file :o) 

using System;
using System.Windows.Forms;

namespace prijimac
{
	public class Class1
	{

		public static void ShowNumber(int a, int b)
		{
			MessageBox.Show("a=" + a.ToString()+ " b=" + b.ToString());
		}

	}
}

Essentially, you have to reproduce in C# what is given below as the code for a C++  DLL (given the name mycdll for example) containing one function MyCDllRoutine. Note that given the calling convention used, this will export a symbol _MyCDllRoutine@8 in the generated symbol table mycdll.lib (note the preservation of case, the added leading underscore and the decoration @8). The Fortran code to produce a Console application (so that you can write to the screen) that calls the DLL is given below the C++ code. In order for the Fortran program to work, the file mycdll.lib must be added to the Fortran project and the mycdll.dll code added to the folder containing the Fortran executable.

// mycdll.cpp : Defines the entry point for the DLL application.
//

#include "stdafx.h"

// myDLL.cpp : Defines the entry point for the DLL application.
//
#include "stdafx.h"
#include "iostream.h"
#include "stdlib.h"

BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
      )
{
    return TRUE;
}

   extern "C" __declspec(dllexport)  void  __stdcall MyCDllRoutine(int a, int b) ;


// MAIN ENTRY FUNCTION
void  __stdcall MyCDllRoutine (int a, int b)
{
	char achar[10], bchar[10], str[80];

itoa(a,achar,10); 
itoa(b,bchar,10);
strcpy(str," a = ");
strcat(str,achar);
strcat(str,", b = ");
strcat(str,bchar);
cout <<" Entered MyCDllRoutine in the C++ DLL"< 

Fortran Code:

!****************************************************************************
!
!  PROGRAM: testmycdll
!
!  PURPOSE:  Entry point for 'Hello World' sample console application to access
!			 a routine held in a Win32 Dynamic link library compiled from C++ code
!
!****************************************************************************

	program testmycdll

implicit none
!
INTEGER I,J

       INTERFACE
       SUBROUTINE MYCDLLROUTINE (I,J)

       !DEC$ ATTRIBUTES DLLIMPORT :: MYCDLLROUTINE
       !DEC$ ATTRIBUTES STDCALL :: MYCDLLROUTINE
       !DEC$ ATTRIBUTES ALIAS:'_MyCDllRoutine@8' :: MYCDLLROUTINE
	   INTEGER I,J

       END SUBROUTINE MYCDLLROUTINE
       END INTERFACE

 print *, 'Hello World'
 I=10
 J=25

       CALL MYCDLLROUTINE(I,J)

	end program testmycdll

The following was somehow chopped off the end of the C++ code:

cout <<" Entered MyCDllRoutine in the C++ DLL"< 

MessageBox(HWND_DESKTOP,str,"Two numbers sent to C++ DLL",MB_OK);
}