ComponentsThreadPool::submit()

ThreadPool::submit() ​

(PHP 8.6+, True Async 1.0)

php
public ThreadPool::submit(callable $task, mixed ...$args): Async\Future

Adds a task to the pool's internal queue. A free worker picks it up, executes it, and resolves the returned Future with the return value. If the queue is full, the calling coroutine is suspended until a slot opens.

Parameters ​

ParameterTypeDescription
$taskcallableThe callable to execute in a worker thread. Deep-copied into the worker — closures capturing objects or resources will throw Async\ThreadTransferException.
...$argsmixedAdditional arguments passed to $task. Also deep-copied.

Return Value ​

Async\Future — resolves with the return value of $task, or rejects with any exception thrown by $task.

Exceptions ​

  • Async\ThreadPoolException — thrown immediately if the pool has been closed via close() or cancel().
  • Async\ThreadTransferException — thrown if $task or any argument cannot be serialized for transfer (e.g. stdClass, PHP references, resources).

Examples ​

Example #1 Basic submit and await ​

php
<?php

use Async\ThreadPool;
use function Async\spawn;
use function Async\await;

spawn(function() {
    $pool = new ThreadPool(workers: 2);

    $future = $pool->submit(function(int $n) {
        $sum = 0;
        for ($i = 0; $i < $n; $i++) {
            $sum += $i;
        }
        return $sum;
    }, 1_000_000);

    echo await($future), "\n"; // 499999500000

    $pool->close();
});

Example #2 Handling exceptions from a task ​

php
<?php

use Async\ThreadPool;
use function Async\spawn;
use function Async\await;

spawn(function() {
    $pool = new ThreadPool(workers: 2);

    $future = $pool->submit(function() {
        throw new \RuntimeException('something went wrong in the worker');
    });

    try {
        await($future);
    } catch (\RuntimeException $e) {
        echo "Caught: ", $e->getMessage(), "\n";
        // Caught: something went wrong in the worker
    }

    $pool->close();
});

Example #3 Submitting multiple tasks in parallel ​

php
<?php

use Async\ThreadPool;
use function Async\spawn;
use function Async\await;

spawn(function() {
    $pool = new ThreadPool(workers: 4);

    $futures = [];
    for ($i = 1; $i <= 8; $i++) {
        $futures[] = $pool->submit(function() use ($i) {
            return $i * $i;
        });
    }

    foreach ($futures as $f) {
        echo await($f), "\n";
    }

    $pool->close();
});

See Also ​