Coroutine::cancel

Cancel coroutine execution.

Coroutine::cancel ​

(PHP 8.6+, True Async 1.0)

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

Cancels the coroutine execution. The coroutine will receive an AsyncCancellation exception at the next suspension point (suspend, await, delay, etc.).

Cancellation works cooperatively -- the coroutine is not interrupted instantly. If the coroutine is inside protect(), cancellation is deferred until the protected section completes.

Parameters ​

cancellation : The exception serving as the cancellation reason. If null, a default AsyncCancellation is created.

Examples ​

Example #1 Basic cancellation ​

php
<?php

use function Async\spawn;
use function Async\suspend;
use function Async\await;

$coroutine = spawn(function() {
    try {
        Async\delay(10000);
    } catch (\Async\AsyncCancellation $e) {
        echo "Cancelled: " . $e->getMessage() . "\n";
    }
});

suspend();

$coroutine->cancel();

await($coroutine);

Example #2 Cancellation with reason ​

php
<?php

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

$coroutine = spawn(function() {
    Async\delay(10000);
});

$coroutine->cancel(new \Async\AsyncCancellation("Timeout exceeded"));

try {
    await($coroutine);
} catch (\Async\AsyncCancellation $e) {
    echo $e->getMessage() . "\n"; // "Timeout exceeded"
}

Example #3 Cancellation before start ​

php
<?php

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

$coroutine = spawn(function() {
    return "should not complete";
});

// Cancel before the scheduler starts the coroutine
$coroutine->cancel();

try {
    await($coroutine);
} catch (\Async\AsyncCancellation $e) {
    echo "Coroutine cancelled before start\n";
}

See Also ​