LISTEN(3XNET) X/Open Networking Services Library Functions LISTEN(3XNET)

NAME

listen - listen for socket connections and limit the queue of
incoming connections

SYNOPSIS

cc [ flag ... ] file ... -lxnet [ library ... ]
#include <sys/socket.h>

int listen(int socket, int backlog);

DESCRIPTION

The listen() function marks a connection-mode socket, specified by
the socket argument, as accepting connections, and limits the number
of outstanding connections in the socket's listen queue to the value
specified by the backlog argument.


If listen() is called with a backlog argument value that is less than
0, the function sets the length of the socket's listen queue to 0.


The implementation may include incomplete connections in the queue
subject to the queue limit. The implementation may also increase the
specified queue limit internally if it includes such incomplete
connections in the queue subject to this limit.


Implementations may limit the length of the socket's listen queue.
If backlog exceeds the implementation-dependent maximum queue length,
the length of the socket's listen queue will be set to the maximum
supported value.


The socket in use may require the process to have appropriate
privileges to use the listen() function.

RETURN VALUES

Upon successful completions, listen() returns 0. Otherwise, -1 is
returned and errno is set to indicate the error.

ERRORS

The listen() function will fail if:

EBADF
The socket argument is not a valid file descriptor.


EDESTADDRREQ
The socket is not bound to a local address, and the
protocol does not support listening on an unbound
socket.


EINVAL
The socket is already connected.


ENOTSOCK
The socket argument does not refer to a socket.


EOPNOTSUPP
The socket protocol does not support listen().


The listen() function may fail if:

EACCES
The calling process does not have the appropriate
privileges.


EINVAL
The socket has been shut down.


ENOBUFS
Insufficient resources are available in the system to
complete the call.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO

accept(3XNET), connect(3XNET), socket(3XNET), attributes(7),
standards(7)

June 10, 2002 LISTEN(3XNET)