# example
{
    # this scope is here just to localize the signal handler

    local $SIG{ALRM} = sub { die "timeout\n" };
    alarm $TIMEOUT;

    eval {
        # iffy code

        1;
    } or do {
        die $@ unless $@ eq "timeout\n"; # propagate other exceptions

        # handle timeout
    };
    alarm 0; # free alarm
}