I want to use thread_group for multi-thread, and maybe using it like this: void thread2(); void thread1(boost::thread_group& tg) { // create an other thread in the thread_group tg.create_thread(thread2); // do some work for(;;) { //... } } void thread2() { // do some work for(;;) { //... } } int main() { boost::thread_group tg; tg.create_thread(boost::bind(thread1, boost::ref(tg))); tg.join_all(); return 0; } I am puzzling about the join_all() function. Whether is it safe to invoke boost::thread_group::create_thread in an other thread and the join_all will wait for all the tow thread? I saw the source code of thread_group. It used a std::list to keep thread objects, and used a shared_mutex for synchronization. It lock on create_thread and shared lock on join_all. Is that mean if it run on "tg.join_all()" in main thread before "tg.create_thread(thread2);" in thread1, the "tg.create_thread(thread2);" will lead to a dead-lock because the "tg.join_all()" wait for thread1 finish, and thread1 wait for "tg.join_all()" finish on "tg.create_thread(thread2);" If it is so, how can I implement such a function? Thank you. -- View this message in context: http://old.nabble.com/Question-about-the-boost%3A%3Athread_group-tp27220440p... Sent from the Boost - Users mailing list archive at Nabble.com.