Coroutine::cancel
(PHP 8.6+, True Async 1.0)
public Coroutine::cancel(?Async\AsyncCancellation $cancellation = null): void
取消协程的执行。协程将在下一个挂起点（suspend、await、delay 等）收到 AsyncCancellation 异常。
取消操作是协作式的——协程不会被立即中断。如果协程正在 protect() 内部，取消将被推迟到受保护区段完成后。
参数
- cancellation
- 作为取消原因的异常。如果为
null，则创建默认的AsyncCancellation。
示例
示例 #1 基本取消
<?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);
示例 #2 带原因的取消
<?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"
}
示例 #3 启动前取消
<?php
use function Async\spawn;
use function Async\await;
$coroutine = spawn(function() {
return "should not complete";
});
// 在调度器启动协程之前取消
$coroutine->cancel();
try {
await($coroutine);
} catch (\Async\AsyncCancellation $e) {
echo "Coroutine cancelled before start\n";
}
参见
- Coroutine::isCancelled – 检查是否已取消
- Coroutine::isCancellationRequested – 检查取消请求
- Cancellation – 取消概念
- protect() – 受保护区段