$SIG{ALRM} = \&timed_out;
eval {
    alarm (10);
    $buf = <>;
    alarm(0);           # Cancel the pending alarm if user responds.
};
if ($@ =~ /GOT TIRED OF WAITING/) {
    print "Timed out. Proceeding with default\n";
    ....
}

sub timed_out {
    die "GOT TIRED OF WAITING";
}

##</code><code>##

C:\>perl -e "print join ' ', keys %SIG"
STOP NUM05 NUM06 ALRM NUM07 NUM24 NUM16 NUM17 NUM18 NUM19 ILL CHLD SEGV PIPE CLD
 ABRT CONT INT QUIT KILL BREAK TERM NUM01 FPE NUM10 NUM12