If no error occurs, this function returns zero. Otherwise, it returns SOCKET_ERROR, and a specific error code is available in lpErrno.

Note:
The Windows Embedded CE version of this function does not support the exchange of data at the time of connection for the default service provider. The default value for lpCalleeDataand lpCallerDatashould both be NULL.

On a blocking socket, the return value indicates success or failure of the connection attempt. If the return error code indicates the connection attempt failed (that is, WSAECONNREFUSED, WSAENETUNREACH, WSAETIMEDOUT) the Windows Sockets SPI client can call WSPConnectagain for the same socket.

The following table shows the possible error codes.

This function is used to create a connection to the specified destination and to perform a number of other ancillary operations that occur at connect time as well. If the socket, s, is unbound, unique values are assigned to the local association by the system and the socket is marked as bound.

For connection-oriented sockets (for example, type SOCK_STREAM), an active connection is initiated to the specified host using name(an address in the name space of the socket. (For a detailed description, see WSPBind.) When this call completes successfully, the socket is ready to send and receive data. If the address member of the namestructure is all zeroes, WSPConnectwill return the error WSAEADDRNOTAVAIL. Any attempt to reconnect an active connection will fail with the error code WSAEISCONN.

For connection-oriented, nonblocking sockets it is often not possible to complete the connection immediately. In such a case, this function returns with the error WSAEWOULDBLOCK but the operation proceeds. When the success or failure outcome becomes known, it may be reported in one of several ways depending on how the client registers for notification. If the client uses WSPSelect, success is reported in the writefdsset and failure is reported in the exceptfdsset. If the client uses WSPEventSelect, the notification is announced with FD_CONNECT and the error code associated with the FD_CONNECT indicates either success or a specific reason for failure.

For a connectionless socket (for example, type SOCK_DGRAM), the operation performed by WSPConnectis to establish a default destination address so the socket can be used with subsequent connection-oriented send and receive operations ( WSPSend, WSPRecv). Any datagrams received from an address other than the destination address specified will be discarded. If the address member of the namestructure is all zeroes, the socket will be disconnected— the default remote address will be indeterminate, so WSPSendand WSPRecvcalls will return the error code WSAENOTCONN. However, WSPSendToand WSPRecvFromcan still be used. The default destination can be changed by simply calling WSPConnectagain, even if the socket is already connected. Any datagrams queued for receipt are discarded if nameis different from the previous WSPConnect.

For connectionless sockets, namecan indicate any valid address, including a broadcast address. However, to connect to a broadcast address, a socket must have WSPSetSockOptSO_BROADCAST enabled. Otherwise, WSPConnectwill fail with the error code WSAEACCES.

On connectionless sockets, exchange of user-to-user data is not possible and the corresponding parameters will be silently ignored.

The Windows Sockets SPI client is responsible for allocating any memory space pointed to directly or indirectly by any of the parameters it specifies.

The lpCallerDatais a value parameter that contains any user data to be sent along with the connection request. If lpCallerDatais NULL, no user data will be passed to the peer. The lpCalleeDatais a result parameter that will reference any user data passed back from the peer as part of the connection establishment. The lpCalleeData->leninitially contains the length of the buffer allocated by the Windows Sockets SPI client and pointed to by lpCalleeData->buf. The lpCalleeData->lenwill be set to zero if no user data has been passed back. The lpCalleeDatainformation will be valid when the connection operation is complete. For blocking sockets, this will be when the WSPConnectfunction returns. For nonblocking sockets, this will be after the FD_CONNECT notification has occurred. If lpCalleeDatais NULL, no user data will be passed back. The exact format of the user data is specific to the address family the socket belongs to and/or the applications involved.