topic Re: Error with the IFX compiler when I call a Fortran subroutine from C# in Intel® Fortran Compiler

Error with the IFX compiler when I call a Fortran subroutine from C#

dj1967 — Tue, 29 Apr 2025 15:03:17 GMT

Hello,

I'm using Intel Fortran 2024.1 and Visual Studio 2022 Professional.

When I call a basic Fortran subroutine from C# I don't get any errors get with the IFORT compiler. However when I switch to the IFX compiler, I get the following error:

System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)
at CallDLL_64.Program.MYSUB64(Int32& ic, Int32& idiag, String filename, Int32 L1)
at CallDLL_64.Program.Main(String[] args)

The Fortran code is:

MODULE DllInterface

IMPLICIT NONE

CONTAINS

!DEC$ ATTRIBUTES DLLEXPORT::MYSUB64

!DEC$ ATTRIBUTES ALIAS : "MYSUB64" :: MYSUB64

SUBROUTINE MYSUB64(ic, idiag, filename)

IMPLICIT NONE

INTEGER*4, INTENT(INOUT) :: ic, idiag

CHARACTER*(*) :: filename

!--------------------------- Body of program --------------------------

ic = 1

idiag = 2

RETURN

END

END MODULE DllInterface

The C# code is

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace CallDLL_64
{
class Program
{
[DllImport(@"..\\..\\..\\bin\\x64\\myDLL.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern void MYSUB64(ref int ic, ref int idiag, string filename, int L1);

static void Main(string[] args)
{

int ic;
int idiag;
string X = "Hello";
int L1;

try
{

ic = 0;
idiag = 0;
L1 = X.Length;
MYSUB64(ref ic, ref idiag, X, L1);

}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
}
}

What am I doing wrong?

Thanks

Re: Error with the IFX compiler when I call a Fortran subroutine from C#

Ron_Green — Tue, 29 Apr 2025 15:32:21 GMT

The ifort project is also x64 or is it ia32 project?

Re: Error with the IFX compiler when I call a Fortran subroutine from C#

Ron_Green — Tue, 29 Apr 2025 15:37:21 GMT

Here is an interesting thread on compiling the C# for x64/ia32. The BadFormatException occurs when there is a mismatch between the calling C# program and the DLL in x64 vs ia32

Re: Error with the IFX compiler when I call a Fortran subroutine from C#

Ron_Green — Tue, 29 Apr 2025 17:29:58 GMT

I don't know much about C#, but I did build a DLL from your code. Using a default DLL project configuration. In the thread I mentioned, https://stackoverflow.com/questions/5229768/c-sharp-compiling-for-32-64-bit-or-for-any-cpu

(i forgot to put this in the last reply).
from a web search I learned you can tell if a DLL is ia32 or x64 by bringing the binary DLL into Notepad or Notepad+ and looking for the string "PE. " followed by either a letter:

Determining DLL Architecture:

You can determine if a DLL is 32-bit or 64-bit by opening it in a text editor (like Notepad++) and searching for the "PE" header. The character following "PE" indicates the architecture. For 32-bit DLLs, the character after "PE" will be "L", while for 64-bit DLLs, it will be "t".

The default for ifx is "t" which as expected is a x64 DLL. So I think your C# code must be looking for a 32bit DLL

Re: Error with the IFX compiler when I call a Fortran subroutine from C#

dj1967 — Wed, 30 Apr 2025 10:10:22 GMT

Both are x64.

Re: Error with the IFX compiler when I call a Fortran subroutine from C#

dj1967 — Wed, 30 Apr 2025 10:27:16 GMT

Hello Ron

I've opened the IFX DLL with Notepad and the header says:

MZx @ x º ´ Í!¸LÍ!This program cannot be run in DOS mode.$ PE d† .ùh ð

The IFORT DLL also says

PE d†

Is there anything wrong?

Thanks.