(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.
如果成功则返回 TRUE，失败则返回 FALSE。
Example#1 posix_setuid() example
This example will show the currrent user id and then set it to a different value.
<?php
echo posix_getuid()."\n"; //10001
echo posix_geteuid()."\n"; //10001
posix_setuid(10000);
echo posix_getuid()."\n"; //10000
echo posix_geteuid()."\n"; //10000
?>