LISTEN(2) System Calls Manual LISTEN(2)
listen - listen for connections on a socket
int listen(s, backlog)
int s, backlog;
To accept connections, a socket is first created with socket(2), a
backlog for incoming connections is 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 will receive an error with an indication of ECON-
0 on success.
-1 on failure and sets errno to indicate the error.
EBADF s is not a valid descriptor.
ENOTSOCK s is not a socket.
EOPNOTSUPP The socket is not of a type that supports listen().
accept(2), connect(2), socket(2)
The backlog is currently limited (silently) to 5.
21 January 1990 LISTEN(2)