Making C++ DLL for C#

Question

I have made a very simple Dll like this:

extern \"C\"
{
  __declspec(dllexport) int Try(int v)
  {
    return 10 + v;
  }
}

Then I want to use

Answer 1

The default calling convention in C and C++ is __cdecl; the default calling convention used by .NET P/Invoke is __stdcall -- you need to reconcile these two.

• Either make your native function __stdcall, as Hans suggested:

  __declspec(dllexport) int __stdcall Try(int v)
  

• Or make your managed P/Invoke signature use __cdecl:

  [DllImport("TestLib.dll", CallingConvention = CallingConvention.Cdecl)]
  public static extern int Try(int v);