note 126692 added to function.pcntl-alarm

Beware that pcntl_signal will interrupt (u)sleep calls which will not be resumed once the handler is completed. It's a documented behaviour (https://www.php.net/manual/en/function.sleep.php) although it may look like a bug when encountered for the first time. From the docs: "If the call was interrupted by a signal, sleep() returns a non-zero value. On Windows, this value will always be 192 (the value of the WAIT_IO_COMPLETION constant within the Windows API). On other platforms, the return value will be the number of seconds left to sleep." ``` <?php $interval = 1; pcntl_async_signals(true); pcntl_signal(SIGALRM, function () use ($interval): void { echo 'SIGALRM called' . PHP_EOL; pcntl_alarm($interval); }); pcntl_alarm($interval); echo 'Sleep (will be interrupted) started' . PHP_EOL; sleep(100000000000); echo 'Sleep ended soon due to interrupt' . PHP_EOL; $sleepTimeout = 10; echo "Proper sleep for {$sleepTimeout} seconds" . PHP_EOL; $startedAt = time(); while ($sleepTimeout > 0 && ($sleepTimeout = sleep($sleepTimeout)) !== true) { echo "Sleep interrupted, {$sleepTimeout} seconds remaining" . PHP_EOL; } $elapsed = time() - $startedAt; echo "Sleep finished after {$elapsed} seconds" . PHP_EOL; ``` ---- Server IP: 45.112.84.4 Probable Submitter: 45.112.85.242 (proxied: 2a02:830a:b206:0:941d:5f10:af20:5f9d) ---- Manual Page -- https://php.net/manual/en/function.pcntl-alarm.php Edit -- https://main.php.net/note/edit/126692 Del: integrated -- https://main.php.net/note/delete/126692/integrated Del: useless -- https://main.php.net/note/delete/126692/useless Del: bad code -- https://main.php.net/note/delete/126692/bad+code Del: spam -- https://main.php.net/note/delete/126692/spam Del: non-english -- https://main.php.net/note/delete/126692/non-english Del: in docs -- https://main.php.net/note/delete/126692/in+docs Del: other reasons-- https://main.php.net/note/delete/126692 Reject -- https://main.php.net/note/reject/126692 Search -- https://main.php.net/manage/user-notes.php