P/Invoke and strings callback problem

[olekba]

Hi All,

I have a problem with found a bug here. Maybe someone can help me. From c# I call a c++ function (in dll via P/Invoke). One function give a handle form manage code to a unmanage code. Next after call another function from manage code unmanage call this callback in manage. In c# it is look like:

[DllImport("tttddd.dll", CharSet = CharSet.Ansi)]
        public static extern void  CallBackFire();

        public delegate void InterfaceGroupEvent([MarshalAs(UnmanagedType.LPStr)]  string ord);

        [DllImport("tttddd.dll", CharSet = CharSet.Ansi)]
        public static extern void set_InterfaceGroupEventCallback(InterfaceGroupEvent f);

        private void button1_Click(object sender, EventArgs e)
        {
            set_InterfaceGroupEventCallback(InterfaceGroupEventCallbackFunction);
            CallBackFire();
        }

        public void InterfaceGroupEventCallbackFunction( string str)
        {
            MessageBox.Show(str);
        }

Unmanage part:

static const void*(*InterfaceGroupEventCallback)(char*);
__declspec(dllexport)void set_InterfaceGroupEventCallback(const void*(*f)(char*))
{
	InterfaceGroupEventCallback=f;
}

__declspec(dllexport)void CallBackFire()
{
	char *s=(char*)CoTaskMemAlloc(100);
	sprintf(s,"Cat");
	InterfaceGroupEventCallback(s);
}

All look to work good in runtime (message box is show) but next come a bug:

"Run-Time Check Failure #0 - The value of ESP was not properly saved across a function call. THis is usually a result of calling a function declared with one calling convention with a function pointer declared with a different calling convention"

But funtions look to have same conventions....

Any ideas ?

Thnx in advance

Olekba