Function listen

Place a socket in a state where it is listening for an incoming connection.

int listen(SOCKET socket, int backlogsize);

Parameters

socket

Bound and unconnected socket returned by socket.

backlogsize

Maximum number of pending connections allowed.

return value

Returns 0 if successful, otherwise SOCKET_ERROR. If an error occurred, call xn_getlasterror and xn_geterror_string to return the error value. Section Error Codes further describes each error. Possible values for this function are:

Value	Meaning
EINVAL	The socket has not been bound.
EISCONN	The socket is already connected or listening.
EMFILE	Out of ports.
ENOTINITIALIZED	RTIP-32 has not been initialized (xn_rtip_init has not been called).
ENOTSOCK	Invalid socket descriptor.
EOPNOTSUPPORT	Socket type not supported for this function.

This function establishes a queue for an incoming connection on a socket. After calling listen, server applications call accept to establish a connection with a client and an associated socket and then create a new thread for the connection. The listen call allows a backlog of client connection requests to be queued up for processing by the server. Without listen, the client connection requests would be rejected.

If backlogsize contains an invalid value (less than 1 or greater than CFG_TCP_MAX_CONN), backlogsize is set to the nearest valid value.

This function is for TCP only.

Left Socket API

Function ioctlsocket

Down Function ntohl