From: Mark <okmooi@...>
Date: 2006-10-23T20:40:25+09:00
Subject: Trouble using puts and getc in different threads

Hi,

I was trying to do a little exercise: Display series of numbers
(1,2,3,4, 5....etc) in an infinite loop. The program should quit if
someone hits a specific key (ENTER in my case as the escape key
requires ugly solutions for non-buffered input). Sounds simple, right?
Not. I thought this should work:

$done = FALSE

Thread.new do
  STDIN.getc
  $done = TRUE
end

i = 0
while !$done
  i = i + 1
  puts i
end
puts "We're done here..."

It doesn't work. What I see is the loop running until i equals 60 then
the loop stops! When I press ENTER, the program stops (as expected).

If I replace STDIN.getc by a sleep(3) then the loop runs for 3 seconds
as expected and the program terminates.

My conclusion: using puts and getc in different threads causes
trouble. Why is this? How can this be fixed? Should I go about the
'loop until key pressed'-problem' in an entirely different way?

Thanx!
Mark