[FR-devel] Yet another Win32 thread bug - how to reproduce

[Laurent Julliard]

Lyle,

I thought the popen_test.rb file I posted before was working but 
actually it wasn't. I have reshaped popen_test.rb to make the thread 
problem even more visible on Win32. Here is the new program:

(please other FR developpers tell me if this program runs correctly 
and which Ruby platform/version do you use)

----- beginning of script -----------

command = "ruby -e 'loop { STDOUT.sync=true;sleep 5; puts 'Ding!'}'"

f = IO.popen(command)

th1 = Thread.new {
  loop {
    begin
      text = f.sysread(100)
      print text
    rescue EOFError
      puts "Remote program stopped"
      exit
    end
  }
}

th2 = Thread.new(0) { |i|
  loop { sleep 1; puts i=i+1 }
}

th1.join
th2.join

----- end of script -----------


On Linux (Ruby 1.6.6.) the output is exactly what one would expect:

1
2
3
4
Ding!
5
6
7
8
9
Ding!
10

On Win32 (Ruby 1.7.3+ from CVS including the recent fix for mswin32 
threads) the (wrong) output is :

Ding!1

Ding!2

Ding!3


What happens is that the sysread call in th1 which is a blocking read 
most of the time prevents th2 from running or it rather looks like th2 
is given a chance to print something only when th1 does print 
something itself once every 5 seconds.

I think this the root cause of all our troubles at least in FreeRIDE 
and may be in FOX addInput() as well. Do you think it's a real bug or 
is there something wrong in my program?

Laurent