use strict;
use warnings;

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

sub do_work {
    my $var = 0;
    for (1 .. 1000000) {
        for (1 .. 1000000) {
            $var++;
        }
    }
}