Hello, I tried to modify the sample code from Bill Kempf for boost.thread, listing 4 that I got at the following link http://www.cuj.com/documents/s=8470/cuj0205kempf/list4.htm to embed the write function in a writeClass function-object. That is a test because in a program I need to pass a function object to one thread, and not a global function. I simply wrote this code: class writerClass { public: ~writerClass() { // for Debug std::cout << "writerClass dtor" << std::endl; } void operator() () { for (int n = 0; n < ITERS; ++n) { { boost::mutex::scoped_lock lock(io_mutex); std::cout << "sending: " << n << std::endl; } buf.put(n); } } }; and changed in the main() --> boost::thread thrd2(&writer); with --> boost::thread thrd2((writerClass())); Everything works the same, but I have the destructor of wirterClass called 4 times, when constructing thrd2!!! That's weird to me, but it's annoying because in my other program, the dtor destroys some member data, and the program crashes because of it. Why is the ~writerClass() called? is there maybe some exception thrown?? how can I solve the problem? thank you ricky P.S. if it can be useful, during the compilation I get a warning (MSVC 7.1), but I read that it can be safely ignored: warning C4275: non dll interface class "boost::noncopyable_::noncopyable" used as a base for dll interface class "boost::mutex" [...]\boost\noncopyable.hpp(22): see declaration of "boost::noncopyable_::noncopyable" [...]\boost\thread\mutex.hpp(33): see declaration of "boost::mutex"