Why can't swoole use sleep?

Because in swoole, using the sleep function will cause the process to fall into sleep blocking; only signals can interrupt the sleep process. Since swoole's signal is based on signalfd, sleep cannot be interrupted even if a signal is sent. The operating system will not reawaken the current process until the specified time.

The operating environment of this tutorial: Windows 10 system, Swoole 4 version, DELL G3 computer

Why swoole cannot be used with sleep

In In asynchronous IO programs, sleep/usleep/time_sleep_until/time_nanosleep must not be used. (sleep is used below to refer to all sleep functions)

• The sleep function will cause the process to fall into sleep blocking

• until the specified time has elapsed and the operating system Only then will the current process be reawakened

• During the sleep process, only signals can interrupt

• Since Swoole's signal processing is implemented based on signalfd , so sleep cannot be interrupted even if a signal is sent

The swoole_event_add, swoole_timer_tick, swoole_timer_after, swoole_process::signal, and asynchronous swoole_client provided by Swoole will stop working after the process sleeps. swoole_server can no longer handle new requests.

Instance program

$serv = new swoole_server("127.0.0.1", 9501);
$serv->set(['worker_num' => 1]);
$serv->on('receive', function ($serv, $fd, $from_id, $data) {
    sleep(100);
    $serv->send($fd, 'Swoole: '.$data);
});
$serv->start();

The sleep function is executed in the onReceive event, and the server cannot receive any more client requests within 100 seconds.

Recommended learning: swoole tutorial

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