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OpenSwoole\Coroutine::cancel

Latest version: pecl install openswoole-25.2.0 | composer require openswoole/core:22.1.5

Declaration

<?php
OpenSwoole\Coroutine::cancel(int $cid): bool

Parameters

cid

Coroutine ID, the coroutine ID you want to cancel/terminate. You cannot cancel the current coroutine.

Return

Returns true if the coroutine was successfully cancelled and false if there was a problem, use OpenSwoole\Util::getLastErrorCode() to see what went wrong.

Experimental feature, not recommended for production use

Description

Cancel the execution (terminate) of a coroutine based on a coroutine ID. You can get the ID of a coroutine with Coroutine::getCid(), this allows you to then cancel that coroutine but you can't cancel (terminate) the current coroutine you are in.

Coroutine cancel error codes (get with OpenSwoole\Util::getLastErrorCode()):

OpenSwoole\Constant::ERROR_CO_CANNOT_CANCEL
OpenSwoole\Constant::ERROR_CO_NOT_EXISTS
OpenSwoole\Constant::ERROR_CO_CANCELED

You can use OpenSwoole\Coroutine::isCanceled() to check if a coroutine has been cancelled.

Since v4.7.0


Examples

You should not cancel the current coroutine or non-existing coroutines.

<?php
use OpenSwoole\Coroutine;

co::run(function()
{
    assert(Coroutine::cancel(Coroutine::getCid()) === false);
    assert(OpenSwoole\Util::getLastErrorCode() === OpenSwoole\Constant::ERROR_CO_CANNOT_CANCEL);

    assert(Coroutine::cancel(999) === false);
    assert(OpenSwoole\Util::getLastErrorCode() === OpenSwoole\Constant::ERROR_CO_NOT_EXISTS);
});

Cancel a coroutine after Co::suspend/Co::yield

<?php
use OpenSwoole\Coroutine;
use OpenSwoole\Coroutine\System;

co::run(function()
{
    $cid = Coroutine::getCid();

    go(function() use ($cid)
    {
        System::usleep(2000);
        assert(Coroutine::cancel($cid) === true);
    });

    $retval = Coroutine::yield();
    echo "Done\n";
    assert($retval === false);
    assert(OpenSwoole\Util::getLastErrorCode() === OpenSwoole\Constant::ERROR_CO_CANCELED);
});

Cancel a coroutine related to AsyncIO

<?php
use OpenSwoole\Coroutine;
use OpenSwoole\Event;
use OpenSwoole\Coroutine\System;
use function OpenSwoole\co::run;

co::run(function()
{
    $cid = Coroutine::getCid();

    Event::defer(function() use ($cid)
    {
        assert(Coroutine::cancel($cid) === true);
    });

    $retval = System::gethostbyname('openswoole.com');
    echo "Done\n";
    assert($retval === false);
    assert(OpenSwoole\Util::getLastErrorCode() === OpenSwoole\Constant::ERROR_AIO_CANCELED);
});

Last updated on September 21, 2022
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