sunos man page for listen

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)