listen - Listen for socket connections and limits the
backlog of incoming connections
int backlog );
Interfaces documented on this reference page conform to
industry standards as follows:
listen(): XNS4.0, XNS5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Specifies the unique name for the socket. Specifies the
maximum number of outstanding connection requests.
The listen() function identifies the socket that receives
the connections, marks the socket as accepting connections,
and limits the number (backlog) of outstanding connection
requests in the system queue.
The maximum queue length (backlog) that the listen() function
can specify is indicated by the somaxconn kernel
attribute in the socket subsystem. Use the sysconfig -q
socket somaxconn to obtain this value from the kernel. See
sys_attrs_socket(5) for more information.
The socket in use may require that the process have appropriate
privileges to use the listen() function.
Upon successful completion, the listen() function returns
a value of 0 (zero). Otherwise, a value of -1 is returned
and errno is set to indicate the error.
If the listen() function fails, errno may be set to one of
the following values: The requested address is protected
and the current process does not have permission to access
it. The socket parameter is not valid. The socket is not
bound to a local address, and the protocol does not support
listening on an unbound socket. The socket is
already connected; or the socket is shut down. Insufficient
resources are available in the system to complete
the call. The socket parameter refers to a file, not a
socket. The referenced socket is not a type that supports
the listen() function.
Functions: accept(2), connect(2), socket(2)
Network Programmer's Guide
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