posix_setgid(3) [php man page]

POSIX_SETGID(3) 							 1							   POSIX_SETGID(3)

posix_setgid - Set the GID of the current process

SYNOPSIS

       bool posix_setgid (int  $gid)

DESCRIPTION

	Set  the real group 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. The appropriate order of function calls is posix_setgid(3) first, posix_setuid(3) last.

       Note

	       If the caller is a super user, this will also set the effective group id.

PARAMETERS

	      o $gid
		- The group id.

RETURN VALUES

	Returns TRUE on success or FALSE on failure.

EXAMPLES

       Example #1

	      posix_setgid(3) example

	       This example will print out the effective group id, once it is changed.

	      <?php
	      echo 'My real group id is '.posix_getgid(); //20
	      posix_setgid(40);
	      echo 'My real group id is '.posix_getgid(); //40
	      echo 'My effective group id is '.posix_getegid(); //40
	      ?>

SEE ALSO

       posix_getgrgid(3), posix_getgid(3).

PHP Documentation Group 													   POSIX_SETGID(3)