listen()

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(2), and then the connections are accepted with accept(2). The listen(2) 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

The listen(2) call 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(2).

BUGS

The backlog is currently limited (silently) to 5 or the value in the registry entry HKLM\SYSTEM\Current\CurrentControlSet\Services\FtpSvc\ListenBacklog to a maximum of 5 for NT 4.0 Workstation, 100 on NT 3.51 (Workstation & Server) and 200 on NT 4.0 Server.

SEE ALSO

accept(2)

connect(2)

socket(2)