From: ts <decoux@...>
Date: 2002-11-06T01:05:02+09:00
Subject: Re: UDPSocket - bidirectional communication through one socket?

>>>>> "W" == Wejn  <lists+rubytalk@box.cz> writes:

W>   I'm trying to write threaded application which will communicate
W> (in both directions) through UDP (first thread for reading, second
W> for writing).

 Well, probably UDP is not the best ...

W>   My problem is that I'm unable to get it to work ... I admit I'm not expert
W> in this field, but it simply hangs on recvfrom(). The problem is that select()
W> reports 'read data ready' even if there are NO data and thus it remains
W> locked :( I tried to wrap it in timeout(){} block ... but the result
W> is still the same ... it locks after first recvfrom(). :(

 How do you use ::select ?

W> Is there anybody who got this to work properly? Please, speak up ... :)

pigeon% cat b.rb
#!/usr/bin/ruby
require 'socket'
$count = 4

m = Thread.new do
   a = UDPSocket.new
   a.bind('pigeon', 6666)
   mesg = 0
   while true
      if IO.select([a], nil, nil, 0)
         p a.recvfrom(1024)[0]
         mesg += 1
         break if mesg == $count
      else
         p "..."
         sleep 0.5
      end
   end
end

Thread.new do
   b = UDPSocket.new
   $count.times do |i|
      sleep 1
      b.send("hello #{i}", 0, 'pigeon', 6666)
   end
end.join

m.join
pigeon% 

pigeon% b.rb
"..."
"..."
"hello 0"
"..."
"..."
"hello 1"
"..."
"..."
"hello 2"
"..."
"..."
"hello 3"
pigeon% 



Guy Decoux