(PHP 4, PHP 5)
posix_setuid — Set the UID of the current process
Set the real user ID of the current process. This is a privileged function that needs appropriate privileges (usually root) on the system to be able to perform this function.
The user id.
成功时返回 TRUE， 或者在失败时返回 FALSE.
Example #1 posix_setuid() example This example will show the current user id and then set
it to a different value.
<?php
echo posix_getuid()."
"; //10001
echo posix_geteuid()."
"; //10001
posix_setuid(10000);
echo posix_getuid()."
"; //10000
echo posix_geteuid()."
"; //10000
?>