public int nabtoRpcInvoke(IntPtr session, string nabtoUrl, out string resultJson) { IntPtr nativeResult; var status = Win32NativeMethods.nabtoRpcInvoke(session, nabtoUrl, out nativeResult); if (status == NABTO_OK || status == NABTO_FAILED_WITH_JSON_MESSAGE) { resultJson = MoveString(nativeResult); } else { resultJson = null; } return(status); }