(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
socket_listen — Listens for a connection on a socket
After the socket socket has been created
using socket_create() and bound to a name with
socket_bind(), it may be told to listen for incoming
connections on socket.
socket_listen() is applicable only to sockets of
type SOCK_STREAM or
SOCK_SEQPACKET.
socketA Socket instance created with socket_create() or socket_addrinfo_bind()
backlog
A maximum of backlog incoming connections will be
queued for processing. 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 may succeed.
Note:
The maximum number passed to the
backlogparameter highly depends on the underlying platform. On Linux, it is silently truncated toSOMAXCONN. On win32, if passedSOMAXCONN, the underlying service provider responsible for the socket will set the backlog to a maximum reasonable value. There is no standard provision to find out the actual backlog value on this platform.
Returns true on success or false on failure. The error code can be retrieved with
socket_last_error(). This code may be passed to
socket_strerror() to get a textual explanation of the
error.
<?php
// create for tcp
$sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_bind($sock, '127.0.0.1',5000);
socket_listen($sock,1);
sleep(20);
?>
<fruit>
netstat -ntpl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:5000 0.0.0.0:* LISTEN 1839/php