Future::cancel

(PHP 8.6+, True Async 1.0)

public function cancel(?AsyncCancellation $cancellation = null): void

Cancels the Future. All coroutines awaiting this Future via await() will receive a CancelledException. If the $cancellation parameter is provided, it will be used as the cancellation reason.

Parameters

cancellation — a custom cancellation exception. If null, the default CancelledException is used.

Return value

The function does not return a value.

Examples

Example #1 Basic Future cancellation

<?php

use Async\Future;
use Async\FutureState;

$state = new FutureState();
$future = new Future($state);

// A coroutine awaiting the result
\Async\async(function() use ($future) {
    try {
        $result = $future->await();
    } catch (\Async\CancelledException $e) {
        echo "Future cancelled\n";
    }
});

// Cancel the Future
$future->cancel();

Example #2 Cancellation with a custom reason

<?php

use Async\Future;
use Async\FutureState;
use Async\AsyncCancellation;

$state = new FutureState();
$future = new Future($state);

\Async\async(function() use ($future) {
    try {
        $future->await();
    } catch (\Async\CancelledException $e) {
        echo "Reason: " . $e->getMessage() . "\n";
        // Reason: Timeout exceeded
    }
});

$future->cancel(new AsyncCancellation("Timeout exceeded"));

Documentation