Doc #74479 [Opn->Csd]: usleep with large numbers

Edit report at https://bugs.php.net/bug.php?id=74479&edit=1 ID: 74479 Updated by: cmb@php.net Reported by: korchasa at gmail dot com Summary: usleep with large numbers -Status: Open +Status: Closed Type: Documentation Problem Package: Unknown/Other Function Operating System: Ubuntu 16.04.2 with 4.8.0-46 PHP Version: 5.6.30 Block user comment: N Private report: N New Comment: Automatic comment on behalf of cmbecker69@gmx.de Revision: http://git.php.net/?p=doc/en.git;a=commit;h=95bc76b545a00d436239af6d5516f75ff890df56 Log: Fix #74479: usleep with large numbers Previous Comments: ------------------------------------------------------------------------ [2020-08-11 12:28:30] cmb@php.net While usleep() has been removed from POSIX.1-2008, formerly that standard has been mandated that[1] | The useconds argument shall be less than one million. and | The usleep() function may fail if: | [EINVAL] | The time interval specified one million or more microseconds. So a general emulation for larger intervals is out of scope. Changing to doc issue. [1] <https://pubs.opengroup.org/onlinepubs/009695399/functions/usleep.html> ------------------------------------------------------------------------ [2017-04-20 15:00:32] daverandom@php.net This is a 32-bit integer overflow issue, it will happen regardless of platform because there is an explicit (unsigned int) cast when the underlying usleep(3) is called. https://lxr.room11.org/xref/php-src%40master/ext/standard/basic_functions.c#4520 I would argue that you shouldn't use usleep() to sleep for that kind of time anyway - if you are sleeping for 12 hours, sub-second precision doesn't really matter and is not reasonable to expect. However in 64-bit environments the expected behaviour could be emulated. ------------------------------------------------------------------------ [2017-04-20 14:32:05] korchasa at gmail dot com Description: ------------ usleep works strange on large numbers Test script: --------------- <?php $start = microtime(true); usleep(4294967296 + 1000000); echo round(microtime(true) - $start); Expected result: ---------------- 12h pause and 4296 in output or error message Actual result: -------------- 1 second pause and 1 in output ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=74479&edit=1