diff --git a/ChangeLog b/ChangeLog
index e5ea44c824..7ff4007373 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Apr 28 23:53:15 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* lib/thwait.rb: revise rdoc.  a patch from Roger Pack in
+	  [ruby-core:27362].
+
 Wed Apr 28 23:21:42 2010  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* ext/json: Update to JSON 1.4.2.
diff --git a/lib/thwait.rb b/lib/thwait.rb
index 6785431c4d..e13ae074d5 100644
--- a/lib/thwait.rb
+++ b/lib/thwait.rb
@@ -3,37 +3,6 @@
 #   	$Release Version: 0.9 $
 #   	$Revision: 1.3 $
 #   	by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd.)
-#
-# --
-#  feature:
-#  provides synchronization for multiple threads.
-#
-#  class methods:
-#  * ThreadsWait.all_waits(thread1,...)
-#    waits until all of specified threads are terminated.
-#    if a block is supplied for the method, evaluates it for
-#    each thread termination.
-#  * th = ThreadsWait.new(thread1,...)
-#    creates synchronization object, specifying thread(s) to wait.
-#
-#  methods:
-#  * th.threads
-#    list threads to be synchronized
-#  * th.empty?
-#    is there any thread to be synchronized.
-#  * th.finished?
-#    is there already terminated thread.
-#  * th.join(thread1,...)
-#    wait for specified thread(s).
-#  * th.join_nowait(threa1,...)
-#    specifies thread(s) to wait.  non-blocking.
-#  * th.next_wait
-#    waits until any of specified threads is terminated.
-#  * th.all_waits
-#    waits until all of specified threads are terminated.
-#    if a block is supplied for the method, evaluates it for
-#    each thread termination.
-#
 
 require "thread.rb"
 require "e2mmap.rb"
@@ -50,6 +19,11 @@ require "e2mmap.rb"
 #     STDERR.puts "Thread #{t} has terminated."
 #   end
 #
+#   
+#   th = ThreadsWait.new(thread1,...)
+#   th.next_wait # next one to be done
+#    
+#
 class ThreadsWait
   RCS_ID='-$Id: thwait.rb,v 1.3 1998/06/26 03:19:34 keiju Exp keiju $-'
 
@@ -59,7 +33,7 @@ class ThreadsWait
 
   #
   # Waits until all specified threads have terminated.  If a block is provided,
-  # it is executed for each thread termination.
+  # it is executed for each thread as they terminate.
   #
   def ThreadsWait.all_waits(*threads) # :yield: thread
     tw = ThreadsWait.new(*threads)
@@ -82,18 +56,18 @@ class ThreadsWait
     join_nowait(*threads) unless threads.empty?
   end
 
-  # Returns the array of threads in the wait queue.
+  # Returns the array of threads that have not terminated yet.
   attr :threads
 
   #
-  # Returns +true+ if there are no threads to be synchronized.
+  # Returns +true+ if there are no threads in the pool still running.
   #
   def empty?
     @threads.empty?
   end
 
   #
-  # Returns +true+ if any thread has terminated.
+  # Returns +true+ if any thread has terminated and is ready to be collected.
   #
   def finished?
     !@wait_queue.empty?