(PHP 4 >= 4.0.2, PHP 5, PHP 7, PHP 8)
posix_setegid — Set the effective GID of the current process
$group_id): boolSet the effective group ID of the current process. This is a privileged function and needs appropriate privileges (usually root) on the system to be able to perform this function.
group_idThe group id.
成功時(shí)返回 true， 或者在失敗時(shí)返回 false。
示例 #1 posix_setegid() example
This example will print out the effective group id, once changed.
<?php
echo 'My real group id is '.posix_getgid(); //20
posix_setegid(40);
echo 'My real group id is '.posix_getgid(); //20
echo 'My effective group id is '.posix_getegid(); //40
?>