listen(2) [opendarwin man page]

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

listen(3SOCKET) 					     Sockets Library Functions						   listen(3SOCKET)

NAME

       listen - listen for connections on a socket

SYNOPSIS

       cc [ flag ... ] file ... -lsocket  -lnsl  [ library ... ]
       #include <sys/types.h>
       #include <sys/socket.h>

       int listen(int s, int backlog);

DESCRIPTION

       To  accept  connections, a socket is first created with	socket(3SOCKET), a backlog for incoming connections is specified with listen() and
       then the connections are accepted with  accept(3SOCKET). 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 will receive an error with an indication of ECONNREFUSED for  AF_UNIX sock-
       ets.  If  the  underlying protocol supports retransmission,  the connection request may be ignored so that retries may succeed. For AF_INET
       and AF_INET6sockets, the TCP will retry the connection. If the  backlog is not cleared by the time the tcp times out, the connect will fail
       with ETIMEDOUT.

RETURN VALUES

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

ERRORS

       The call fails if:

       EBADF	     The argument s is not a valid file descriptor.

       ENOTSOCK      The argument s is not a socket.

       EOPNOTSUPP    The socket is not of a type that supports the operation listen().

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       accept(3SOCKET), connect(3SOCKET), socket(3SOCKET), attributes(5), socket.h(3HEAD)

NOTES

       There is currently no backlog limit.

SunOS 5.11							    8 Nov 1999							   listen(3SOCKET)