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@gmail.com>
Filip Klasson <filkl784@student.liu.se> 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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