<?php

declare(strict_types=1);

/**

* This example shows how to use locks across threads.

*

* Once executed, it prints out "12345678". The numbers printed out are to show the order of the code execution.

*

* Note that this example works only on Swoole 6.0.0 or later, with ZTS (Zend Thread Safety) enabled.

*

* How to run this script:

* docker run --rm -v "$(pwd):/var/www" -ti phpswoole/swoole:6.0-zts php ./examples/locks/lock-across-threads.php

*/

use Swoole\Thread;

use Swoole\Thread\Lock;

if (version_compare(SWOOLE_VERSION, '6.0.0', '<')) {

fwrite(STDERR, 'Error: Swoole 6.0.0 or higher is required. Current version: ' . SWOOLE_VERSION . PHP_EOL);

exit(1);

}

$args = Thread::getArguments();

if (!isset($args)) { // The main thread.

$lock = new Lock();

$threads = [];

$threads[] = new Thread(__FILE__, 1, $lock);

$threads[] = new Thread(__FILE__, 2, $lock);

foreach ($threads as $thread) {

$thread->join();

}

echo '8', PHP_EOL;

} else {

$i = $args[0];

$lock = $args[1];

if ($i === 1) { // First child thread.

echo '1';

assert($lock->lock() === true, 'Lock the lock for the first time successfully.');

usleep(5000); // Sleep for 5 milliseconds.

echo '4';

assert($lock->unlock() === true, 'Unlock the lock successfully.');

echo '5';

} else { // Second child thread.

echo '2';

assert($lock->trylock() === false, 'Failed to lock a locked lock.');

echo '3';

assert($lock->lock() === true, 'Lock the lock for the second time successfully.');

echo '6';

assert($lock->unlock() === true, 'Unlock the lock successfully.');

echo '7';

}

}