// If one of the callbacks throws an exception we must stop the loop

$loop->stop();

Event loop abstraction layer that libraries can use for evented I/O.

In order for async based libraries to be interoperable, they need to use the

same event loop. This component provides a common `LoopInterface` that any

library can target. This allows them to be used in the same loop, with one

single `run` call that is controlled by the user.

In addition to the interface there are some implementations provided:

* `stream_select`: This is the only implementation which works out of the box

with PHP. It does a simple `select` system call. It's not the most performant

of loops, but still does the job quite well.

* `libevent`: This uses the `libevent` pecl extension. `libevent` itself

supports a number of system-specific backends (epoll, kqueue).

All of the loops support these features:

* File descriptor polling

* One-off timers

* Periodic timers

Here is an async HTTP server built with just the event loop.

$loop = React\EventLoop\Factory::create();

$server = stream_socket_server('tcp://127.0.0.1:8080');

stream_set_blocking($server, 0);

$loop->addReadStream($server, function ($server) use ($loop) {

$conn = stream_socket_accept($server);

$data = "HTTP/1.1 200 OK\r\nContent-Length: 3\r\n\r\nHi\n";

$loop->addWriteStream($conn, function ($conn) use (&$data, $loop) {

$written = fwrite($conn, $data);

if ($written === strlen($data)) {

fclose($conn);

$loop->removeStream($conn);

} else {

$data = substr($data, 0, $written);

}

});

});

$loop->addPeriodicTimer(5, function () {

$memory = memory_get_usage() / 1024;

$formatted = number_format($memory, 3).'K';

echo "Current memory usage: {$formatted}\n";

});

$loop->run();

**Note:** The factory is just for convenience. It tries to pick the best

available implementation. Libraries `SHOULD` allow the user to inject an

instance of the loop. They `MAY` use the factory when the user did not supply

a loop.

"php": ">=5.3.3"

"target-dir": "React/EventLoop",

"extra": {

"branch-alias": {

"dev-master": "0.2"

}

}