LISTEN

Section: Linux Programmer's Manual (2)
Updated: 23 July 1993
Index Return to Main Contents
 

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 VALUE

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.  

ERRORS

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.
 

HISTORY

The listen function call appeared in BSD 4.2.  

BUGS

If the socket is of type af_inet, and the backlog argument is greater than 128 it is silently truncated to 128. For portable applications don't rely on this value since BSD (and at least some BSD derived systems) limit the backlog to 5.  

SEE ALSO

accept(2), connect(2), socket(2)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
HISTORY
BUGS
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 12:25:27 GMT, March 22, 2025