(PHP 4 >= 4.0.2, PHP 5, PHP 7, PHP 8)
posix_seteuid — Set the effective UID of the current process
$user_id): boolSet the effective user 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.
user_idThe user id.
成功時(shí)返回 true， 或者在失敗時(shí)返回 false。