The effective gid of this process. If you are on a machine that supports membership in multiple groups simultaneously, gives a space separated list of groups you are in. The first number is the one returned by getegid()
, and the subsequent ones by getgroups()
, one of which may be the same as the first number.
Similarly, a value assigned to $)
must also be a space-separated list of numbers. The first number sets the effective gid, and the rest (if any) are passed to setgroups()
. To get the effect of an empty list for setgroups()
, just repeat the new effective gid; that is, to force an effective gid of 5 and an effectively empty setgroups()
list, say $) = "5 5"
.
You can change both the effective gid and the real gid at the same time by using POSIX::setgid()
(use only a single numeric argument). Changes to $)
require a check to $!
to detect any possible errors after an attempted change.
$<
, $>
, $(
and $)
can be set only on machines that support the corresponding set[re][ug]id() routine. $(
and $)
can be swapped only on machines supporting setregid()
.
Mnemonic: parentheses are used to group things. The effective gid is the group that's right for you, if you're running setgid.