DllImport StackOverflowException

I'm trying to use C++ DLL(borland c builder) from c#. Function writeParameter works fine, it writes correct data to a file, but then i have an exception "An unhandled exception of type 'System.StackOverflowException' occurred in PresentationFramework.dll"

C++ code:

#include <vcl.h>
#include <windows.h>
#include <fstream.h>
#pragma hdrstop
#pragma argsused
BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fwdreason, LPVOID lpvReserved)
{
  return 1;
}
//---------------------------------------------------------------------------
#pragma pack (push,1)
typedef struct     
{
     int     a;
}ABC;
#pragma pack (pop)
//---------------------------------------------------------------------------

extern "C" void __declspec(dllexport) __cdecl writeParameter(ABC *abc)
{
   ofstream outfile("result.txt");
   outfile<< "A="   <<endl;
   outfile << abc->a <<endl;
   outfile.close();
}

c#:

[StructLayoutAttribute(LayoutKind.Sequential)]
public class ABC
{
    public int a;
}
[DllImport("D:\\monitorVC.dll", EntryPoint = "_writeParameter", CallingConvention = CallingConvention.Cdecl, CharS开发者_StackOverflow中文版et = CharSet.Ansi)]
        public static extern void WriteParameter( 
            [In,MarshalAs(UnmanagedType.LPStruct)]
            ABC abc
            );

        private void Grid_Loaded(object sender, RoutedEventArgs e)
        {
                var abc = new ABC() {a = 123};
                WriteParameter(abc);
        }

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Read this blog post about the very poorly chosen name for UnmanagedType.LPStruct and how it does not do what everybody thinks it does. Fix your declaration like this:

[DllImport(...)]
public static extern void WriteParameter([In] ref ABC abc);

---

class != struct in C#.

Also, the packing of your structure is not the same between the C# version and the C++ version.

---

I know that it's been a while since this question was posted but I had the same experience trying to load to a VS2010 C# project, a .dll built with CodeGear C++ Builder 2007.

The work-around was to remove all TForms from my .dll. It seemed to me that the exported symbols from these forms (which by the way I could not remove) where "leading" the loader to a stack overflow.

Regards.