From: Dave Thomas <dave@...>
Date: 2008-02-10T13:19:38+09:00
Subject: Synced IO seems not to be thread-safe

Take the following code:

STDOUT.sync = true
threads = (1..4).map do |number|
   Thread.new(number) do |i|
     print "#{i}\n"
   end
end
threads.each { |t|  t.join }


Run like this:

ruby t.rb >t.op

And inspect the output

$ od -c t.op
0000000    2  \n
0000002

You get something different every time :)

dave[RUBY3/Book 22:18:25] ruby t.rb >t.op
dave[RUBY3/Book 22:18:26] od -c t.op
0000000    2  \n  \0  \0   4  \n
0000006

Without the STDOUT.sync, the problem goes away.



Dave