Re: [Boost-users] [thread] more problems with condition

From: Frank Mori Hess (fmhess_at_[hidden])
Date: 2008-04-19 19:19:46

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On Saturday 19 April 2008 10:23, Frank Mori Hess wrote:
> On Saturday 19 April 2008 06:48, Anteru wrote:
> > Well, I still have problems with the conditions, even with the latest
> > SVN. The problem seems to be that inside a block like:
>
> Does the attached patch help?  I do my development on Linux, so it's
> completely untested.

Actually, I no longer think my earlier patch was useful.  But what if the 
last notify_one() happens between the WaitForSingleObject() call in 
do_wait() and the start_wait_loop() call in the next iteration of the 
while loop?  I don't understand the boost.thread code 100%, but it seems 
like it could be missed.  The attached patch should eliminate that 
possibility.

- -- 
Frank

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Index: boost/thread/win32/condition_variable.hpp
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=2D-- boost/thread/win32/condition_variable.hpp	(revision 44607)
+++ boost/thread/win32/condition_variable.hpp	(working copy)
@@ -164,7 +164,6 @@
                                  detail::win32::handle_manager& local_wake=
_sem,
                                  detail::win32::handle_manager& sem)
             {
=2D                boost::mutex::scoped_lock internal_lock(internal_mutex);
                 if(!local_wake_sem)
                 {
                     start_wait_loop_first_time(locker,local_wake_sem);
@@ -184,15 +183,18 @@
=20
                 relocker<lock_type> locker(lock);
            =20
+                boost::unique_lock<boost::mutex> internal_lock(internal_mu=
tex);
                 while(!woken)
                 {
                     start_wait_loop(locker,local_wake_sem,sem);
+                    internal_lock.unlock();
                    =20
                     if(!this_thread::interruptible_wait(sem,wait_until))
                     {
                         return false;
                     }
                =20
+                    internal_lock.lock();
                     unsigned long const woken_result=3Ddetail::win32::Wait=
=46orSingleObject(local_wake_sem,0);
                     BOOST_ASSERT(woken_result=3D=3Ddetail::win32::timeout =
|| woken_result=3D=3D0);
=20

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