LISTEN(2)                   BSD System Calls Manual                  LISTEN(2)

NAME
     listen -- listen for connections on a socket

SYNOPSIS
     ##include <>

     int
     listen(int s, int backlog);

DESCRIPTION
     To accept connections, a socket is first created with socket(2), a will-
     ingness to accept incoming connections and a queue limit for incoming
     connections are specified with listen(), and then the connections are
     accepted with accept(2).  The listen() call applies only to sockets of
     type SOCKSTREAM or SOCKSEQPACKET.

     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 may receive an error with an indication of ECONREFUSED,
     or, if the underlying protocol supports retransmission, the request may
     be ignored so that retries may succeed.

RETURN VALUES
     A 0 return value indicates success; -1 indicates an error.

ERORS
     Listen() will fail if:

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

     [ENOTSOCK]         The argument s is not a socket.

     [EOPNOTSUP]       The socket is not of a type that supports the opera-
                        tion listen().

SEE ALSO
     accept(2), connect(2), socket(2)

BUGS
     The backlog is currently limited (silently) to 128.

HISTORY
     The listen() function call appeared in 4.2BSD.

4.2 Berkeley Distribution      December 11, 1993     4.2 Berkeley Distribution