(PHP 4 >= 4.1.0, PHP 5, PHP 7)

socket_listenListens for a connection on a socket


bool socket_listen ( resource $socket [, int $backlog = 0 ] )

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.



A valid socket resource created with socket_create().


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.


The maximum number passed to the backlog parameter highly depends on the underlying platform. On Linux, it is silently truncated to SOMAXCONN. On win32, if passed SOMAXCONN, 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.


성공 시 TRUE를, 실패 시 FALSE를 반환합니다. 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.


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User Contributed Notes 2 notes

renmengyang567 at gmail dot com
4 years ago
// create for tcp
$sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_bind($sock, '',5000);

netstat  -ntpl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0*               LISTEN      1839/php
Karuna Govind (karuna.kgx gmail)
15 years ago
To change the maximum allowed backlog by your system (*nix machines only), first you need to find the variable for this limit:

sudo sysctl -a | grep somaxconn

On ubuntu boxes, it returns net.core.somaxconn (you need to look for the 'somaxconn' variable, the full name will vary across different systems).

Update this to a large number as follows:

sudo sysctl -w net.core.somaxconn=1024

This will work straight away. no restart required.
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