The socket ioctl opcodes for Winsock 2 are summarized in the following table. More detailed information is provided in section 4 under WSPIoctl. There are other new protocol-specific ioctl opcodes which can be found in the protocol-specific annex.
| Opcode | Input Type | Output Type | Meaning |
|---|---|---|---|
| FIONBIO | unsigned long | <non used> | Enable or disable non-blocking mode on the socket. |
| FIONREAD | <not used> | unsigned long | Determine the amount of data which can be read atomically from the socket. |
| SIOCATMARK | <not used> | BOOL | Determine whether or not all out-of-band data has been read. |
| SIO_ASSOCIATE_HANDLE | companion API dependent | <not used> | Associate the socket with the specified handle of a companion interface. |
| SIO_ENABLE_CIRCULAR _QUEUEING |
<not used> | <not used> | Circular queuing is enabled. |
| SIO_FIND_ROUTE | struct sockaddr | <not used> | Request the route to the specified address to be discovered. |
| SIO_FLUSH | <not used> | <not used> | Discard current contents of the sending queue. |
| SIO_GET_BROADCAST _ADDRESS |
<not used> | struct sockaddr | Retrieve the protocol-specific broadcast address to be used in WSPSendTo. |
| SIO_GET_QOS | <not used> | QOS | Retrieve current flow spec(s) for the socket. |
| SIO_GET_GROUP_QOS | <not used> | QOS | Reserved for future use with socket groups; Retrieve current group flow spec(s) for the group this socket belongs to. |
| SIO_MULTIPOINT _LOOKBACK |
BOOL | <not used> | Control whether data sent in a multipoint session will also be received by the same socket on the local host. |
| SIO_MULTICAST_SCOPE | int | <not used> | Specify the scope over which multicast transmissions will occur. |
| SIO_SET_QOS | QOS | <not used> | Establish new flow spec(s) for the socket. |
| SIO_SET_GROUP_QOS | QOS | <not used> | Reserved for future use with socket groups; Establish new group flow spec(s) for the group this socket belongs to. |
| SIO_TRANSLATE_HANDLE | int | companion API dependent | Obtain a corresponding handle for socket s that is valid in the context of a companion interface. |
| SIO_ROUTING_INTERFACE_QUERY | SOCKADDR | SOCKADDR | Obtain the address of local interface which should be used to send to the specified address |
| SIO_ROUTING_INTERFACE_CHANGE | SOCKADDR | <not used> | Request notification of changes in information reported via SIO_ROUTING_INTERFACE_QUERY for the specified address |
| SIO_ADDRESS_LIST_QUERY | <not used> | SOCKET_ADDRESS_LIST | Obtain the list of addresses to which application can bind. |
| SIO_ADDRESS_LIST_CHANGE | <not used> | <not used> | Request notification of changes in information reported via SIO_ADDRESS_LIST_QUERY |
| SIO_QUERY_PNP_TARGET_HANDLE | <not used> | SOCKET | Obtain socket descriptor of the next provider in the chain on which current socket depends in PnP sense |