TaskGroup::cancel

(PHP 8.6+, True Async 1.0)

public TaskGroup::cancel(?Async\AsyncCancellation $cancellation = null): void

Cancels all running coroutines and queued tasks. Implicitly calls seal(). Queued tasks are never started.

Coroutines receive an AsyncCancellation and terminate. Cancellation happens asynchronously — use awaitCompletion() to guarantee completion.

Parameters

cancellation

The exception serving as the cancellation reason. If null, a standard AsyncCancellation with the message “TaskGroup cancelled” is used.

Examples

Example #1 Cancellation with waiting for completion

<?php

use Async\TaskGroup;

spawn(function() {
    $group = new TaskGroup();

    $group->spawn(function() {
        Async\delay(10000);
        return "long task";
    });

    $group->cancel();
    $group->awaitCompletion();

    echo "all tasks cancelled\n";
});

Example #2 Cancellation with a reason

<?php

use Async\TaskGroup;

spawn(function() {
    $group = new TaskGroup();
    $group->spawn(fn() => Async\delay(10000));

    $group->cancel(new \Async\AsyncCancellation("Timeout exceeded"));
    $group->awaitCompletion();
});

See Also

• TaskGroup::seal — Seal without cancellation
• TaskGroup::awaitCompletion — Wait for completion
• TaskGroup::dispose — Dispose of the group scope