$SIG{HUP} = sub { print "Framework handler!\n"; };

##</code><code>##

$SIG{HUP} = sub { print "FooApp handler!\n"; };

##</code><code>##

my $old_handler = $SIG{HUP};
$SIG{HUP} = sub {
    print "Framework handler!\n";
    $old_handler->(@_) if defined $old_handler;
}