This example will print out the effective group id, once it is
changed with posix_setegid().
<?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 ?>
Notes
posix_getegid() is different than
posix_getgid() because effective group ID can be changed by
a calling process using posix_setegid().
See Also
posix_getgrgid() for information on how
to convert this into a useable group name