about libev
libev is an event loop: you register interest in certain events (such as a file descriptor being readable or a timeout occurring), and it will manage these event sources and provide your program with events.
那么什么是libev呢，从网上摘录一段:
libev 是高性能事件循环/事件模型的网络库，并且包含大量新特性。
它是继lievent和event perl module之后的一套全新网络库。它追求的目标：速度更快，bug更少，特性更多，体积更小。 www.2cto.com
它和libevent很像，按照作者的介绍，可以作为libevent的替代者，能够提供更高的性能。并不需要复杂的配置。
看起来和之前提到的libevent大有渊源，但是这个扩展的作者显然比较活跃，一周内提交了3个版本。
代码示例
timer的使用
stop();
// stop the watcher if further calls cause more than 10 iterations
ev::iteration() >= 10 and $w->stop();
});
// 创建一个已停止的timer，手工start才有效
$w_stopped = evtimer::createstopped(10, 5, function($w) {
echo callback of a timer created as stopped\n;
// stop the watcher after 2 iterations
ev::iteration() >= 2 and $w->stop();
});
// loop until ev::stop() is called or all of watchers stop
ev::run();
// start and look if it works
$w_stopped->start();
echo run single iteration\n;
ev::run(ev::run_once);
echo restart the second watcher and try to handle the same events, but don't block\n;
$w2->again();
ev::run(ev::run_nowait);
$w = new evtimer(10, 0, function() {});
echo running a blocking loop\n;
ev::run();
echo end\n;
?>
输出内容
2 seconds elapsed
is called every second, is launched after 2 seconds
iteration = 1
is called every second, is launched after 2 seconds
iteration = 2
is called every second, is launched after 2 seconds
iteration = 3
is called every second, is launched after 2 seconds
iteration = 4
is called every second, is launched after 2 seconds
iteration = 5
run single iteration
callback of a timer created as stopped
restart the second watcher and try to handle the same events, but don't block
running a blocking loop
is called every second, is launched after 2 seconds
iteration = 8
is called every second, is launched after 2 seconds
iteration = 9
is called every second, is launched after 2 seconds
iteration = 10
end
i/o事件
例1
例2
stop();
// stop write watcher
$w->stop();
$in = head / http/1.1\r\n;
$in .= host: google.co.uk\r\n;
$in .= connection: close\r\n\r\n;
if (!socket_write($socket, $in, strlen($in))) {
trigger_error(failed writing $in to socket, e_user_error);
}
$read_watcher = new evio($socket, ev::read, function ($w, $re)
use ($socket, $e_nonblocking) {
// socket is readable. recv() 20 bytes using non-blocking mode
$ret = socket_recv($socket, $out, 20, msg_dontwait);
if ($ret) {
echo $out;
} elseif ($ret === 0) {
// all read
$w->stop();
socket_close($socket);
return;
}
// caught einprogress, eagain, or ewouldblock
if (in_array(socket_last_error(), $e_nonblocking)) {
return;
}
$w->stop();
socket_close($socket);
});
ev::run();
});
$result = socket_connect($socket, $address, $service_port);
ev::run();
?>
输出
http/1.1 301 moved permanently
location: http://www.google.co.uk/
content-type: text/html; charset=utf-8
date: sun, 23 dec 2012 16:08:27 gmt
expires: tue, 22 jan 2013 16:08:27 gmt
cache-control: public, max-age=2592000
server: gws
content-length: 221
x-xss-protection: 1; mode=block
x-frame-options: sameorigin
connection: close
http://www.bkjia.com/phpjc/477830.htmlwww.bkjia.comtruehttp://www.bkjia.com/phpjc/477830.htmltecharticleev is a pecl extension providing inteface to libev library high performance full-featured event loop written in c. about libev libev is an event loop: you register interest in certa...