Caveat: I've had little occasion to do much with udp sockets. See also Perl Cookbook (I hope that is a sanctioned link)

However, udp is connectionless, so you do not need an accept loop. Essentially you want to wait for upto a specified number of seconds for a datagram to arrive and do something else if not. So,

my $hSocket = IO::Socket::INET->new(
    LocalPort=>$intListenPort, 
    Proto=>$strProtocol
) or die "Can't create UDP socket: $@";
ioctl($hSocket, 0x8004667e, pack("I", 1));

my( $gotone, $datagram, $flags) = 0;
my $endtime = time() + $timeout;
while( time() < $endtime ) {
    sleep 1 and next unless $hSocket->recv($datagram,42,$flags );
    ## Got a datagram.
    ...
    $gotone = 1;
    last;
}
if( $gotone ) {
    ## We processed a datagram within the timelimit
}
else {
    ## we didn't
}
[download]

There are probably better ways of structuring that. And you could probably use select or IO::Select to achieve a similar thing.

Or threads.