ultrix man page for listen

listen(2)							System Calls Manual							 listen(2)

Name
       listen - listen for connections on a socket

Syntax
       listen(s, backlog)
       int s, backlog;

Description
       To accept connections, a socket is first created with a call, a backlog for incoming connections is specified with and then the connections
       are accepted with the call.  The call is needed only for sockets of type SOCK_STREAM or SOCK_SEQPACKET.

       The backlog parameter defines the maximum length the queue of pending connections may grow to.  If a connection request	arrives  with  the
       queue full, the client receives an error with an indication of ECONNREFUSED.

Restrictions
       The backlog is currently limited to 8.

Return Values
       A 0 return value indicates success.  A -1 indicates an error.

Diagnostics
       The call fails under the following conditions:

       [EBADF]	      The argument s is not a valid descriptor.

       [ENOTSOCK]     The argument s is not a socket.

       [EOPNOTSUPP]   The socket is not of a type that supports the operation

See Also
       accept(2), connect(2), socket(2)

																	 listen(2)