...
    $SIG{ALRM} = sub { die 'timeout' };
    ...
    do_work();

sub do_work {
    ...
    eval { ... } ...
    die $@ if 'timeout' eq $@;
    ...
}

##</code><code>##

    my $timed_out = 1;
    TIMEOUT_BLOCK_WITH_UNIQUE_LABEL: {
        local $SIG{ALRM} = sub {
            last TIMEOUT_BLOCK_WITH_UNIQUE_LABEL;
        };
        my $err;
        eval {
            alarm( $seconds );
            do_work();
            1
        } or do {
            $err = $@ || 'Unknown error';
        }
        alarm( 0 );
        die $err
            if $err;
        $timed_out = 0;
    }