[DllImport("mydll.dll",
            CallingConvention = CallingConvention.Cdecl,
            SetLastError = false, CharSet = CharSet.Auto)]
            private static extern bool concatenate(
                string str1, // in
                string str2, // in
                StringBuilder strResult); // out

Question is if that StringBuilder really is equal to a char* in this case.

Reply via email to