$SIG{HUP} = \&doSigHup;

##</code><code>##

use POSIX ();
$sigset=POSIX::SigSet->new();
$action=POSIX::SigAction->new('doSigHup',$sigset,&POSIX::SA_NODEFER);
POSIX::sigaction(&POSIX::SIGHUP, $action);