Undocumented resource_usage parameter of pcntl_wait[pid] function

[mumumu]

https://www.php.net/manual/en/function.pcntl-waitpid.php
https://www.php.net/manual/en/function.pcntl-wait.php

pcntl_wait[pid] take a parameter array &$resource_usage = [], which stores struct rusage [*1] value.

[*1] https://man7.org/linux/man-pages/man2/getrusage.2.html

[philip]

Commit that added this: php/php-src@7e0e888