i'm currently working on a daemonized process that collects UDP packets and processes them for database insertion. i'm running into an issue with blocking IO.

I've been using IO::Select and IO::Socket to create the needed sockets, and check if they're available for reading, but one of the collection sockets ( the UDP socket ) blocks if the UDP buffer has been emptied.

i've looked at the  select function, and ( after the annoying vector packing, etc ) it can be used to return the number of packets in the message buffer, so something like this can be achieved: 

if ($nfound = select($rout = $rin, undef, undef, $time_left)) {
  for (1 .. $nfound) {
    $sock->recv($msg, $MAX_SIZE) or warn "Socket error!: $@\n";
    }

[download]
so that once all the messages have been collected from the buffer, the program can move on and do other things.

my question: is there a similar method in IO::Select ( or IO::Socket )? i've read through the perldoc for both, and haven't seen one ( but i may be experiencing tunnel vision ).

the code i've been using ( that blocks ): 

my $incoming = IO::Socket::INET->new( LocalPort => $MSGPORT,
                                      Proto     => 'udp',
                                      Timeout   => 1);

## some more code...

    while ( $incoming->recv( $msg, $MAX_SIZE ) ) {

        my ( $port, $addr ) = unpack_sockaddr_in( $incoming->peername 
+);
        push @messages, [ $addr, $msg ];
        last if @messages > $MAX_INC_Q_SIZE;
    }

[download]

which works fine, until the message buffer only contains  $MAX_INC_Q_SIZE - 1 messages. then, the socket sits and waits for that one last message before exiting the collect loop and processing.

In reply to IO::Select vs select function by geektron

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