package Sigmund;

use base qw( Tie::Hash );

my $realSig= \%::SIG;

sub TIEHASH {
    return bless {}, shift;
}

sub STORE {
    my( $self, $key, $value )= @_;
    my $prev= $realSig->{$key};
    # Replace this next line with whatever you like:
    warn "Changing $key signal handler.\n";
    $realSig->{$key}= $value;
    return $prev;
}

sub FETCH {
    my( $self, $key )= @_;
    return $realSig->{$key};
}

*::SIG= {};
tie %::SIG, __PACKAGE__;

1;