Calling C++ function from C#

Question

Hi all, I am new to C#. So not able to find why the my code is failing: //hpp file /* Arguments: * IN: data - data to parse * data_length - length of data to parse * OUT: result_length - length of result * error_code - error code if the function fails (0 in success) * * Return value: pointer to result buffer * NULL - if operation fails (error_code is set to the error code) * */ PARSER_API unsigned char *GetResult(unsigned char *data, unsigned short data_length, unsigned short *result_length, unsigned short *error_code); //C# file [DllImport("Parser.dll", EntryPoint="GetResult")] static extern byte[] GetResult( byte[] data, UInt16 data_length, [Out()] UInt16 signature_length, [Out()] UInt16 error_code); public byte[] GetResult() { byte[] str=... ... byte[] res = GetSignature(str, datalen, reslen, errnum); return res; } I am getting error as "Can not marshal return value." Could somebody please help me to figure out what is the problem. Thanks in advance, Sri