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listen(3xnet) [sunos man page]

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(5) 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(5), standards(5) SunOS 5.10 10 Jun 2002 listen(3XNET)

Check Out this Related Man Page

LISTEN(2)						     Linux Programmer's Manual							 LISTEN(2)

NAME
listen - listen for connections on a socket SYNOPSIS
#include <sys/socket.h> int listen(int s, int backlog); DESCRIPTION
To accept connections, a socket is first created with socket(2), a willingness to accept incoming connections and a queue limit for incom- ing connections are 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 may receive an error with an indication of ECONNREFUSED or, if the underlying protocol supports retransmission, the request may be ignored so that retries succeed. NOTES
The behaviour of the backlog parameter on TCP sockets changed with Linux 2.2. Now it specifies the queue length for completely 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 tcp_max_syn_backlog sysctl. When syncookies are enabled there is no logical maximum length and this sysctl setting is ignored. See tcp(7) for more information. RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately. ERRORS
EADDRINUSE Another socket is already listening on the same port. 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 listen operation. CONFORMING TO
Single Unix, 4.4BSD, POSIX 1003.1g draft. The listen function call first appeared in 4.2BSD. BUGS
If the socket is of type AF_INET, and the backlog argument is greater than the constant SOMAXCONN (128 in Linux 2.0 & 2.2), it is silently truncated to SOMAXCONN. Don't rely on this value in portable applications since BSD (and some BSD-derived systems) limit the backlog to 5. SEE ALSO
accept(2), connect(2), socket(2) BSD Man Page 1993-07-23 LISTEN(2)
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