NAME

listen − listen for connections on a socket

SYNOPSIS

cc [ flag ... ] file ... −lsocket −lnsl [ library ... ]

#include <sys/types.h>
#include <sys/sockets.h>

int listen(int s, int backlog);

MT-LEVEL

Unsafe

DESCRIPTION

To accept connections, a socket is first created with socket(3N), a backlog for incoming connections is specified with listen() and then the connections are accepted with accept(3N).  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. 

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(). 

SEE ALSO

accept(3N), connect(3N), socket(3N)

NOTES

There is currently no backlog limit. 

This interface is unsafe in multithreaded applications.  Unsafe interfaces should be called only from the main thread. 

SunOS 5.2  —  Last change: 22 Jan 1993