socket_set_nonblock()

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

Sets nonblocking mode for file descriptor fd

说明

socket_set_nonblock(resource $socket): bool

The socket_set_nonblock() function sets the O_NONBLOCK flag on the socket specified by the$socketparameter.

When an operation(e.g. receive, send, connect, accept,...)is performed on a non-blocking socket, the script will not pause its execution until it receives a signal or it can perform the operation. Rather, if the operation would result in a block, the called function will fail.

参数

$socket: A valid socket resource created with socket_create() or socket_accept().

返回值

成功时返回TRUE，或者在失败时返回FALSE。

范例

socket_set_nonblock() example

<?php
$socket = socket_create_listen(1223);
socket_set_nonblock($socket);
socket_accept($socket);
?>

This example creates a listening socket on all interfaces on port 1223 and sets the socket to O_NONBLOCK mode.socket_accept() will immediately fail unless there is a pending connection exactly at this moment.

参见

socket_set_block()Sets blocking mode on a socket resource
socket_set_option()Sets socket options for the socket
stream_set_blocking()为资源流设置阻塞或者阻塞模式

Beware, when using this function within a loop (i.e. a demon with a socket). The socket_accept(), for example, emits a warning each time there is no incoming connection available to be read. My php error log file got huge in a matter of seconds, eventually crashing the server.
Of course, i used the @ before the function to take care of that problem.
[EDITOR: One can (and should) use socket_select to detect a new connection on a socket (it's a "readable" event)]