connections

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

NAME

     listen -- listen for connections on a socket

SYNOPSIS

     #include <sys/socket.h>

     int
     listen(int s, int backlog);

DESCRIPTION

     To accept connections, a socket is first created with socket(2), a willingness 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 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 may receive an error with an indication of ECONNREFUSED, 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.

ERRORS

     Listen() will fail if:

     [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 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