boost::thread Destructor being called multiple times
I was just curious as to why the class destructor are (apparently) being called multiple times. I have tried searching the archives to no avail (which prompted me to register and post to the mailinglist). #include <boost/thread/thread.hpp> struct TestingClass { TestingClass() { std::cout << "constructor called" << std::endl; } ~TestingClass() { std::cout << "destructor called" << std::endl; } void operator()() { std::cout << "operator() called" << std::endl; } } testclass; void testBoostThread() { boost::thread thrd (testclass); thrd.join(); } int main () { testBoostThread(); return 0; } The output: constructor called destructor called destructor called destructor called destructor called operator() called destructor called I would appreciate if someone can enlighten me on this. Will having the destructor called multiple times be a cause of concern? Will it cause some undefined symptoms? Is there a way to completely avoid this situation?
kaliwanagan wrote:
I was just curious as to why the class destructor are (apparently) being called multiple times. >
[...]
I would appreciate if someone can enlighten me on this. Will having the destructor called multiple times be a cause of concern? Will it cause some undefined symptoms? Is there a way to completely avoid this situation?
The multiple callings on destructor are not on same object. If you add a copy constructor, TestingClass(const TestingClass &) { std::cout << "constructor called" << std::endl; } you will see the constructor being called same times. You can use Boost.Bind to avoid multiple object-copying. struct TestingClass { ... void run() { std::cout << "run() called" << std::endl; } ... } ... void testBoostThread() { boost::thread thrd(boost::bind(&TestingClass::run, &testclass)); thrd.join(); }
Von: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] Im Auftrag von kaliwanagan Gesendet: Samstag, 25. August 2007 15:52 An: boost-users@lists.boost.org Betreff: [Boost-users] boost::thread Destructor being called multiple times
I was just curious as to why the class destructor are (apparently) being called multiple times. I have tried searching the archives to no avail (which prompted me to register and post to the mailinglist).
Boost::thread passes its function object around several times by value, so it gets coyp-constructed and destructed several times. I had the same problem, and used some sort of proxy-class until I realized that boost::bind creates exactly that kind of proxy-objects. So either use boost::bind or boost::mem_fn or std::mem_fun. Best Regards Markus
Hi I m using multiarray to stores edges of an graph. I m reading the data from a csv file. My line is L1,0,0,0,1 Now i m using stringtok and storing the values typedef boost::multi_array<string,2> my_array; typedef my_array::index index; int size =vect.size(); my_array edge(boost::extents[size][size]); boost::stringtok(edge[fir][sec],line,","); How do i use stringtok with multiarray.. Thanks Abhishek Vyas Tata Consultancy Services Mailto: abhishek.v@tcs.com Website: http://www.tcs.com ____________________________________________ Experience certainty. IT Services Business Solutions Outsourcing ____________________________________________ boost-users-bounces@lists.boost.org wrote on 08/27/2007 12:05:43 PM:
Von: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] Im Auftrag von kaliwanagan Gesendet: Samstag, 25. August 2007 15:52 An: boost-users@lists.boost.org Betreff: [Boost-users] boost::thread Destructor being called multiple times
I was just curious as to why the class destructor are (apparently) being called multiple times. I have tried searching the archives to no avail (which prompted me to register and post to the mailinglist).
Boost::thread passes its function object around several times by value, so it gets coyp-constructed and destructed several times. I had the same problem, and used some sort of proxy-class until I realized that boost::bind creates exactly that kind of proxy-objects. So either use boost::bind or boost::mem_fn or std::mem_fun.
Best Regards Markus _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
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participants (4)
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Abhishek V -
gchen -
kaliwanagan -
KLINIK Markus STD2-G (AREVA NP GmbH)