Go ahead. Make sure we have test to demonstrate it's working properly,
and then I'd just have to make it work under Windows.
2005/9/26, Ilya A. Volynets-Evenbakh <ilya@total-knowledge.com>:
> Patch is rather small (attached). Mind if I put it in?
> With this patch one can define any destruction policy for their threads:
> 1. Thread object is destroyed externally. If it's in polite mode,
> destructor will terminate it
> 2. Thread object self-destructs: Derived object overrides onThreadExit()
> function and calls
> delete (this) in there.
>
>
> Ilya A. Volynets-Evenbakh wrote:
>
> > Well,
> > It's about time we go back to exploring this issue.
> >
> > I'm doing some testing in CPPSERv, and it's obvious that if we don't
> > make the changes,
> > nothing is going to work right.
> >
> > I think I'll go ahead and get rid of m_waiter lock alltogether and
> > replace it with pthread_join
> > for *nix, and put big fat error message for Winblows, so that everyone
> > who runs threaded code
> > knows to bug you to fix polite thread destruction there.
> >
> > OK?
> >
> >
> >
> > Alexey Parshin wrote:
> >
> >> It could be WaitForSingleObject(), but I'm not sure. I just never
> >> explored it.
> >>
> >> On 5/21/05, Ilya A. Volynets-Evenbakh <ilya@total-knowledge.com> wrote:
> >>
> >>
> >>> Alexey Parshin wrote:
> >>>
> >>>
> >>>
> >>>> Not that I know of ..
> >>>>
> >>>>
> >>>
> >>> Are you saing there is not way to say "block till thread completes"
> >>> natively??
> >>>
> >>>
> >>>
> >>>> However, in Windows CThread is an object, and I
> >>>> wonder how WaitForSingleObject would work with the thread.. It could
> >>>> be an idea.
> >>>>
> >>>>
> >>>>
> >>>
> >>> You really need to investigate that.
> >>>
> >>>
> >>>
> >>>> On 5/21/05, Ilya A. Volynets-Evenbakh <ilya@total-knowledge.com>
> >>>> wrote:
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>> I think polite mode (at least on Unix) should be handled by
> >>>>> pthread_join, and not the CWaiter.
> >>>>> Is there similar concept in Winblows?
> >>>>>
> >>>>>
> >>>>> Alexey Parshin wrote:
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>> I do use self-destruction sometimes. However that conception is
> >>>>>> limiting us too much. It
> >>>>>> should be another solution.
> >>>>>>
> >>>>>> In the worst possible case, we can drop onThreadExit() whatsoever.
> >>>>>>
> >>>>>> On 5/20/05, Ilya A. Volynets-Evenbakh <ilya@total-knowledge.com>
> >>>>>> wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> I've been thinking about CThread::onThreadExit() function,
> >>>>>>> and realized there is race condition there:
> >>>>>>>
> >>>>>>> thread a creates and starts thread b
> >>>>>>> thread b is executing
> >>>>>>> thread a calls b.terminate()
> >>>>>>> thread b finishes executing threadFunction
> >>>>>>> thread a destroyes thread b object.
> >>>>>>> thread b.onThreadExit() starts executing
> >>>>>>>
> >>>>>>> This will happen even in polite mode, I'm afraid, since
> >>>>>>> onThreadExit is called after m_waiter is unlocked.
> >>>>>>>
> >>>>>>> The only way to make sure this doesn't happen, that I can think
> >>>>>>> of right
> >>>>>>> now,
> >>>>>>> is to impose "self-destruction" paradigm on CThread-derived
> >>>>>>> objects.
> >>>>>>> i.e.
> >>>>>>> 1. CThread is always created on heap
> >>>>>>> 2. CThread objects are never explicitly deleted.
> >>>>>>> 3. there is onExitInternal() handler, that is called after normal
> >>>>>>> onThreadExit() is called,
> >>>>>>> and that does "delete this".
> >>>>>>>
> >>>>>>> This is serious change in usage paradigm, so before going ahead and
> >>>>>>> making such
> >>>>>>> a radical change, I want to know what you think about it all.
> >>>>>>>
> >>>>>>> oO(Perhaps HSquirrel is already using self-destuction paradigm
> >>>>>>> anyways,
> >>>>>>> like I do?)
> >>>>>>>
> >>>>>>> --
> >>>>>>> Ilya A. Volynets-Evenbakh
> >>>>>>> Total Knowledge. CTO
> >>>>>>> http://www.total-knowledge.com
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>
> >>>>> --
> >>>>> Ilya A. Volynets-Evenbakh
> >>>>> Total Knowledge. CTO
> >>>>> http://www.total-knowledge.com
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>
> >>> --
> >>> Ilya A. Volynets-Evenbakh
> >>> Total Knowledge. CTO
> >>> http://www.total-knowledge.com
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >>
> >>
> >
>
> --
> Ilya A. Volynets-Evenbakh
> Total Knowledge. CTO
> http://www.total-knowledge.com
>
>
>
> ? autom4te.cache
> ? buildd
> ? thread.diff
> ? updt.log
> Index: sptk3/CThread.h
> ===================================================================
> RCS file: /cvsroot/sptk/sptk2/sptk3/CThread.h,v
> retrieving revision 1.1
> diff -u -r1.1 CThread.h
> --- sptk3/CThread.h 25 Sep 2005 08:30:11 -0000 1.1
> +++ sptk3/CThread.h 26 Sep 2005 05:24:14 -0000
> @@ -39,7 +39,6 @@
> bool m_running; ///< Flag: is the thread running?
> bool m_politeMode; ///< Flag: does the thread uses the 'polite' mode for shutdown?
> std::string m_name; ///< Thread name
> - CWaiter m_waiter; ///< The synchronization object
> #ifndef _WIN32
> pthread_t m_thread; ///< Thread handle
> #else
> Index: src/CThread.cpp
> ===================================================================
> RCS file: /cvsroot/sptk/sptk2/src/CThread.cpp,v
> retrieving revision 1.8
> diff -u -r1.8 CThread.cpp
> --- src/CThread.cpp 25 Sep 2005 08:47:11 -0000 1.8
> +++ src/CThread.cpp 26 Sep 2005 05:24:14 -0000
> @@ -62,14 +62,7 @@
> }
>
> CThread::~CThread() {
> - //printf("CThread::~CThread() for %s started.\n",m_name);
> - if (m_running && m_politeMode) {
> - // wait till the thread is stopping
> - //printf("CThread::~CThread() for %s waiting politely.\n",m_name);
> - m_waiter.lock();
> - m_waiter.unlock();
> - }
> - //printf("CThread::~CThread() for %s ended.\n",m_name);
> + terminate();
> }
>
> void CThread::terminate() {
> @@ -77,9 +70,15 @@
> m_terminated = true;
>
> if (m_running && m_politeMode) {
> +#ifndef _WIN32
> // wait till the thread is stopping
> - m_waiter.lock();
> - m_waiter.unlock();
> + pthread_join(m_thread,0);
> +#else
> +#warning BIG FAT WARNING: Alexey Parshin still did not implement propper polite thread termination!
> +#warning Bug him _NOW_
> + fprintf(stderr, "BIG FAT WARNING: Alexey Parshin still did not implement propper polite thread termination!\n");
> + fprintf(stderr, "Bug him _NOW_\n");
> +#endif
> }
> }
>
> @@ -106,18 +105,9 @@
> void CThread::runThread() {
> m_terminated = false;
> m_running = true;
> -
> - if (m_politeMode)
> - m_waiter.lock();
> -
> threadFunction();
> -
> - if (m_politeMode)
> - m_waiter.unlock();
> -
> - destroyThread();
> -
> m_running = false;
> + destroyThread();
> }
>
> void CThread::run() {
>
>
>
--
Alexey Parshin,
http://www.sptk.net
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