From: m_seki@...
Date: 2000-10-23T11:44:38+09:00
Subject: [ruby-list:25576] Re: [ruby-talk:5747] Q on Queue


咳です。

英語で書けないのです。

Subject: [ruby-talk:5747] Q on Queue

feldt> I just started looking at Ruby's thread support so I might be missing
feldt> something vital but:
feldt> 
feldt> * In Queue#push:
feldt> 
feldt>   1  def push(obj)
feldt>   2   Thread.critical = true
feldt>   3   @que.push obj
feldt>   4   begin
feldt>   5    t = @waiting.shift
feldt>   6    t.wakeup if t
feldt>   7   rescue ThreadError
feldt>   8    retry
feldt>   9   ensure
feldt>   10   Thread.critical = false
feldt>   11  end
feldt>   12  t.run if t
feldt>   13 end
feldt> 
feldt> does anything prevent the scheduler from scheduling a thread t2 that are
feldt> waiting after t1 (that have been waked up and is about to be run) so that
feldt> it gets the next object in the queue before t1?
feldt> 
feldt> That is:
feldt> @waiting = [t1,t2]
feldt> push o1 wakes up t1
feldt> interrupted at line 11
feldt> push o2 wakes up t2
feldt> t2 pops o1
feldt> t1 pops o2

Queueなのですが、一つのスレッドで
  q.pop # --> o2
  q.pop # --> o1
の順に取り出せたら問題かも知れないけど、
二つのスレッドがどちらが先に取り出せるかは不定だと思うのですが、
どうでしょうか ?
つまり、上は問題ないと思うのですが…