(PHP 5 >= 5.2.0, PHP 7, PHP 8)
posix_initgroups — Calculate the group access list
$username, int $group_id): boolCalculates the group access list for the user specified in name.
usernameThe user to calculate the list for.
group_idTypically the group number from the password file.
成功时返回 true， 或者在失败时返回 false。