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# socket_listen

(PHP 4 >= 4.1.0)

socket_listen -- Listens for a connection on a socket

## Description

bool socket_listen ( resource socket [, int backlog])

Warning
This function is EXPERIMENTAL. The behaviour of this function, the name of this function, and anything else documented about this function may change without notice in a future release of PHP. Use this function at your own risk.

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`.

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 `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.

socket_listen() is applicable only to sockets of type `SOCK_STREAM` or `SOCK_SEQPACKET`.

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.

See also socket_accept(), socket_bind(), socket_connect(), socket_create() and socket_strerror().

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