Re: [boost] [thread] Assertion failed get_system_time_sentinel()

Subject: Re: [boost] [thread] Assertion failed get_system_time_sentinel()
From: Filip Klasson (filkl784_at_[hidden])
Date: 2009-03-31 02:15:53

Ok, thanks for the information. Just one question, Is it still a problem if
i access local variables if i join the thread in the destructor?

2009/3/30 Anthony Williams <anthony.ajw_at_[hidden]>

> Filip Klasson <filkl784_at_[hidden]> writes:
>
> > Here is an example that demonstrates the problem:
> >
> > //TestBoostTimeSentinel.cpp:
> > #include "Test.h"
> >
> > void main()
> > {
> >     for (int i=0; i<100; i++) {
> >         Test* a = new Test();
> >         delete a;
> >     }
> > }
>
> So you are creating an object and immediately destroying it.
>
> > Test::Test(void) : _executorThread(boost::shared_ptr<boost::thread>(new
> > boost::thread(&Test::start, this)))
> > {}
>
> The constructor starts a new thread.
>
> > Test::~Test(void)
> > {}
>
> But the destructor doesn't wait for it to finish.
>
> > void Test::start() {
> >     while (true) {
> >         boost::mutex::scoped_lock lock(_mutex);
> >         while (_prioQueue.empty()) {
> >             _emptyQueueCondition.wait(lock);
> >         }
> >     }
> > }
>
> and the thread body accesses local variables.
>
> This is undefined behaviour --- your threads are outliving the variables
> they are accessing. You need to join with the thread before you destroy
> the object. Since you start the thread in the constructor, it would make
> sense to call join in the destructor.
>
> Test::~Test(void)
> {
>    _executorThread->join();
> }
>
> Anthony
> --
> Author of C++ Concurrency in Action | http://www.manning.com/williams
> just::thread C++0x thread library   | http://www.stdthread.co.uk
> Just Software Solutions Ltd         |
> http://www.justsoftwaresolutions.co.uk
> 15 Carrallack Mews, St Just, Cornwall, TR19 7UL, UK. Company No. 5478976
>
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