Pointer to boost :: thread

Question

I have a thread controlled issue.

My problem is that I want to create a ThreadManager class that should manage the entire thread created and, of course, destroy this thread.

class DerivedInterface { public: DerivedInterface():id("Test"){}; virtual ~DerivedInterface(){}; virtual void run() = 0; virtual std::string getId() = 0; const std::string id ; }; class Object : public DerivedInterface { public: Object():id("VirtualDae"){}; ~Object(){} void run() { std::cout<<"i'M IN RUN"<<std::endl; bool flag = true; while(flag){ //allocate x resources try{ //do some process on resources boost::this_thread::sleep(boost::posix_time::milliseconds(100)); //clean resources } catch(boost::thread_interrupted const& ) { //clean resources std::cout << "Worker thread interrupted" << std::endl; flag = false; } catch(std::exception x){ std::cout<<"exx"<<x.what()<<std::endl; } } } std::string getId(){ return id; } const std::string id ; }; class ThreadManager { public: void createThread(DerivedInterface& t) { boost::thread t1(&DerivedInterface::run, &t); insert(&t1); } } /* * This method insert the pointer of the thread in a * map */ void insert(boost::thread* t1) { boost::mutex::scoped_lock lock(m_mutex); int size = threadsMap.size()+1; std::cout<<"Size :"<<size<<std::endl; threadsMap.insert(std::make_pair(size, t1)); } /* * This method return the pointer of the thread * inserted in a map */ boost::thread* get(int key){ boost::mutex::scoped_lock lock(m_mutex); if(threadsMap.find(key)!=threadsMap.end()){ std::cout<<"non null get"<<std::endl; return threadsMap[key]; }else{ std::cout<<" null get"<<std::endl; return NULL; } } /* * This method stop the thread corrisponding * to the position pos as parameter in the map */ void stop(int pos){ std::cout<<"Stop"<<std::endl; boost::thread* thread = get(pos); std::cout<<"thread null"<<std::endl; if(thread != NULL) { std::cout<<"thread not null"<<std::endl; thread->interrupt(); std::cout << "Worker thread finished" << std::endl; } } private: boost::shared_ptr<boost::thread> _mThread; typedef std::map<int, boost::thread*> ThreadMapT; ThreadMapT threadsMap; std::map<int,boost::thread*>::iterator it; boost::mutex m_mutex; boost::thread_group g; }; int main(){ ThreadManager manager; Object v; // manager.createThread(v); std::cout<<"Interrupt"<<std::endl; boost::thread *t1= manager.get(1); t1->interrupt(); // boost::posix_time::time_duration timeout = boost::posix_time::milliseconds(10000); if (manager.get(1)->timed_join(timeout)) { //finished std::cout << "Worker thread finished" << std::endl; } else { //Not finished; std::cout << "Worker thread not finished" << std::endl; } } 

t1.interrupt or manager.stop returns a segmantation error.

 Program terminated with signal 11, Segmentation fault. #0 0x00007f3e1d095993 in boost::thread::get_thread_info() const () from libboost_thread.so.1.51.0 (gdb) where #0 0x00007f3e1d095993 in boost::thread::get_thread_info() const () from libboost_thread.so.1.51.0 #1 0x00007f3e1d0965c6 in boost::thread::interrupt() () from libboost_thread.so.1.51.0 #2 0x00000000004088a9 in main () 

The boost :: thread pointer is not null, so what happens? Thank you in advance.

Whey Can't I do something like this?

 boost::thread *t1 = new boost::thread(&DerivedInterface::run, &t); 

Answer 1

 void createThread(DerivedInterface& t) { boost::thread t1(&DerivedInterface::run, &t); insert(&t1); } 

In the above t1 object is created on the stack, then the pointer to t1 inserted into the map, and then t1 goes out of scope and is destroyed, so that all existing pointers to it become invalid.

You can fix this by moving shared_ptr<thread> instead of thread* :

 void insert(boost::shared_ptr<boost::thread>); void createThread(DerivedInterface& t) { boost::shared_ptr<boost::thread> t1(new boost::thread(&DerivedInterface::run, &t)); insert(t1); } 

Or, using r-value references in C ++ 11:

 void insert(boost::thread&& t1); void createThread(DerivedInterface& t) { boost::thread t1(&DerivedInterface::run, &t); insert(std::move(t1)); } 

Alternatively, use boost::thread_group , which does this for you.