прослушивать соединения сокетов и ограничивать очередь входящих соединений (listen for socket connections and limit the queue of incoming connections)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
listen — listen for socket connections and limit the queue of
incoming connections
Синопсис (Synopsis)
#include <sys/socket.h>
int listen(int socket, int backlog);
Описание (Description)
The listen() function shall mark a connection-mode socket,
specified by the socket argument, as accepting connections.
The backlog argument provides a hint to the implementation which
the implementation shall use to limit the number of outstanding
connections in the socket's listen queue. Implementations may
impose a limit on backlog and silently reduce the specified
value. Normally, a larger backlog argument value shall result in
a larger or equal length of the listen queue. Implementations
shall support values of backlog up to SOMAXCONN, defined in
<sys/socket.h>.
The implementation may include incomplete connections in its
listen queue. The limits on the number of incomplete connections
and completed connections queued may be different.
The implementation may have an upper limit on the length of the
listen queue—either global or per accepting socket. If backlog
exceeds this limit, the length of the listen queue is set to the
limit.
If listen() is called with a backlog argument value that is less
than 0, the function behaves as if it had been called with a
backlog argument value of 0.
A backlog argument of 0 may allow the socket to accept
connections, in which case the length of the listen queue may be
set to an implementation-defined minimum value.
The socket in use may require the process to have appropriate
privileges to use the listen() function.
Возвращаемое значение (Return value)
Upon successful completions, listen() shall return 0; otherwise,
-1 shall be returned and errno set to indicate the error.
Ошибки (Error)
The listen() function shall 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 appropriate privileges.
EINVAL The socket has been shut down.
ENOBUFS
Insufficient resources are available in the system to
complete the call.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
accept(3p), connect(3p), socket(3p)
The Base Definitions volume of POSIX.1‐2017, sys_socket.h(0p)
