Return values

The interface functions have HRESULT as return values. The returned values are derived from the ADS Return Codes. Their meaning for TF6311:

Value (Enum)	Value (Numeric)	Description
ADS_E_INVALIDPARM	0x9811070B	Socket not allocated/known, transferred pointer NULL
ADS_E_NOMOREHDLS	0x98110716	No free sockets available. Default: 32 see TCP/UDP RT TcCom Parameter
ADS_E_INCOMPATIBLE	0x9811070E	Socket in wrong state. E.g. Connect() attempt, if a socket was previous used with Listen(); Close() without previous connection; Send() without connection; Socket Listen(), if a Listen() call was already issued.
ADS_E_INVALIDSTATE	0x98110712	TCP/UDP RT object is not in OP mode
ADS_E_INVALIDDATA	0x98110706	Problem with parameter. E.g. pData==NULL for SendData
ADS_E_EXISTS	0x9811070F	Port already used otherwise
ADS_E_PENDING	0x9811071E	Not all data were sent (SendData)
S_OK	0x0	Call successful. IsConnected(): Connection exists
S_FAIL	0x1	Call not successful, general error IsConnected(): Connection does not exist

The values from the range 0x9811 are defined in the enumeration "E_HRESULTAdsErr" (PLC) and corresponding ADS_E_* (C++) "defines".