From: Stefano Crocco <stefano.crocco@...>
Date: 2012-11-18T21:53:40+09:00
Subject: Re: A basic question about Threads

On Sunday 18 November 2012 Assaf Shomer wrote
> Ruby (and generally code) beginner question:
> 
> I'm reading about threads in the pickaxe book.
> To understand what's going on I was trying to run the following code:
> ===============
> threads=[]
> 3.times do |i|
>   threads[i]=Thread.new do
>     puts i
>   end
> end
> ===============
> 
> It ran ok, but nothing appeared on the console. I was expecting each of
> the three threads to print 'their' position in the thread array.
> The point of this exercise was to look at threads while they are working
> concurrently, before calling the thread.join method.
> 
> I guess I'm misunderstanding the concept because this doesn't work.
> 
> my questions are:
> 1. what's wrong with the above code
> 2. can I write a program that will create M threads each of which
> loops from 1 to N and all of them print concurrently to the console
> something like "Thread #{m} is now on number #{n}"
> 
> Thanks.
> 
> --
> Posted via http://www.ruby-forum.com/.

I'm not an expert using threads, but it seems that the program terminates 
before the threads have a chance to do anything. Try putting a sleep 1 after 
the cycle and you'll see what you expect.

Stefano