From: Aleksi Niemela <aleksi.niemela@...>
Date: 2000-09-24T05:51:14+09:00
Subject: [ruby-list:25130] Re: How to check all Thread fin ?

Sakae Kobayashi:
> deadlock 0x810104c: 2:0 (main) - /usr/local/lib/ruby/1.6/thread.rb:178
> /usr/local/lib/ruby/1.6/thwait.rb:103:in `pop': Thread: 
> deadlock (fatal)

Yashi pointed me to this thread as it seems we have some interesting
behaviour here. I'm not sure if this is the patch actually fixes the bug,
but at least I didn't manage to get any error messages afterwards.

Index: thwait.rb
===================================================================
RCS file: /home/cvs/ruby/lib/thwait.rb,v
retrieving revision 1.4
diff -u -r1.4 thwait.rb
--- thwait.rb   2000/09/21 06:37:23     1.4
+++ thwait.rb   2000/09/23 20:44:45
@@ -44,7 +44,7 @@
   
   Exception2MessageMapper.extend_to(binding)
   def_exception("ErrNoWaitingThread", "No threads for waiting.")
-  def_exception("ErrNoFinshedThread", "No finished threads.")
+  def_exception("ErrNoFinishedThread", "No finished threads.")
   
   def ThreadsWait.all_waits(*threads)
     tw = ThreadsWait.new(*threads)
@@ -99,8 +99,9 @@
     @threads.concat threads.flatten
     for th in threads
       Thread.start do
-       th = th.join
-       @wait_queue.push th
+       t = th
+       t = t.join
+       @wait_queue.push t
       end
     end
   end
@@ -131,3 +132,4 @@
 end
 
 ThWait = ThreadsWait
+


====================

And if you wonder why the bug happens, please try this patch and run Sakae
Kobayashi's example again. Tell me if you see some surprises :).


Index: thwait.rb
===================================================================
RCS file: /home/cvs/ruby/lib/thwait.rb,v
retrieving revision 1.4
diff -u -r1.4 thwait.rb
--- thwait.rb   2000/09/21 06:37:23     1.4
+++ thwait.rb   2000/09/23 20:46:32
@@ -44,7 +44,7 @@
   
   Exception2MessageMapper.extend_to(binding)
   def_exception("ErrNoWaitingThread", "No threads for waiting.")
-  def_exception("ErrNoFinshedThread", "No finished threads.")
+  def_exception("ErrNoFinishedThread", "No finished threads.")
   
   def ThreadsWait.all_waits(*threads)
     tw = ThreadsWait.new(*threads)
@@ -99,8 +99,10 @@
     @threads.concat threads.flatten
     for th in threads
       Thread.start do
-       th = th.join
-       @wait_queue.push th
+       t = th
+       put "surprise" if t != th
+       t = t.join
+       @wait_queue.push t
       end
     end
   end
@@ -131,3 +133,4 @@
 end
 
 ThWait = ThreadsWait
+


=============

    - Aleksi