Section: Linux Programmer's Manual (2)
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listen - listen for connections on a socket
int listen(int sockfd, int backlog);
To accept connections, a socket is first created with
a willingness to accept incoming connections and a queue limit for incoming
connections are specified with
and then the connections are
call applies only to sockets of type
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
or, if the underlying protocol supports retransmission, the request may be
ignored so that retries succeed.
The behaviour of the
parameter on TCP sockets changed with Linux 2.2.
Now it specifies the queue length for
established sockets waiting to be accepted, instead of the number of incomplete
connection requests. The maximum length of the queue for incomplete sockets
can be set using the
When syncookies are enabled there is no logical maximum
length and this sysctl setting is ignored.
for more information.
On success, zero is returned. On error, -1 is returned, and
is set appropriately.
Another socket is already listening on the same port.
is not a valid descriptor.
is not a socket.
The socket is not of a type that supports the
function call first appeared in 4.2BSD.
If the socket is of type
argument is greater
than the constant
(128 in Linux 2.0 & 2.2), it is silently truncated
- RETURN VALUE
- CONFORMING TO
- SEE ALSO
linux.jgfs.net manual pages