listen - listen for connections on a socket
int listen (int s, int backlog);
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 each new connection is
accepted with accept(2). The listen call applies only to sockets of type
The backlog parameter defines the maximum length the queue of pending
connections. 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.
A 0 return value indicates success; -1 indicates an error.
The call fails 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
accept(2), connect(2), socket(2)
The backlog is currently limited (silently) to 1000.
The system actually enforces the limit of pending connections as
((3 * backlog) / 2) + 1
For example, a backlog of 32 will allow 49 outstanding connections.
ABI-compliant versions of the above call can be obtained from
PPPPaaaaggggeeee 1111 [ Back ]