man/man3socket/listen.3socket

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 Copyright 1989 AT&T
 Copyright (C) 1999, Sun Microsystems,
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 LISTEN 3SOCKET "Nov 8, 1999"
 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 sockets. 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.