When directed at a process whose UID is not identical to that
of the sending process, signal number zero may fail because
you lack permission to send the signal, even though the process is alive.
-You may be able to determine the cause of failure using C<$!>.
+You may be able to determine the cause of failure using C<%!>.
- unless (kill 0 => $pid or $! == $!{EPERM}) {
+ unless (kill 0 => $pid or $!{EPERM}) {
warn "$pid looks dead";
}
sleep 2; # to avoid dup signals
}
-=head2 Deferred Signals (Safe signals)
+=head2 Deferred Signals (Safe Signals)
In Perls before Perl 5.7.3 by installing Perl code to deal with
signals, you were exposing yourself to danger from two things. First,