Calling C++ function from C#

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

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shimtanny22y ago
Hi I could not figure out, how to marshal the return value correct, but i have a workaround. I have simplified your function by hard coding the length etc. [STAThread] static void Main(string[] args) { Class1 c1 = new Class1(); Console.WriteLine(c1.GetResult()); Console.ReadLine(); } // Helper private string GetResult() { unsafe { int length = 10; byte[] b = new byte[length]; byte* pByte = UnsafeGetResult(); for (int i = 0; i < 10; i++) { b[i] = (*pByte); pByte++; } return Encoding.ASCII.GetString(b); } } [DllImport(@"D:\Software Development\Current Projects\Parser\Debug\Parser.dll", EntryPoint="GetResult")] unsafe static extern byte* UnsafeGetResult(); Cheers Simon