Hi, When we have to create lot of threads dynamicaly it will be better to have a 'pool' of initialized threads (the initialization of a thread takes significant time). Please not that this has nothing to be with the thread_pool class. I'm looking for any work done related to this problem (libraries, emails, ...). Any hints or comments? Thanks in advance Vicente My first thoghts: The cached_threader class interface could be something like class cached_thread; class cached_threader { public: cached_thread launch(boost::function<void()>&); private: friend class cached_thread; void restore(cached_thread); } cached_thread will provide most of the boost::thread operation but some as detach seams not adapted. class cached_thread { friend class cached_threader; cached_threade launch(boost::function<void()>& f); public: cached_thread(); ~cached_thread(); // move support cached_thread(detail::thread_move_t<thread> x); cached_thread& operator=(detail::thread_move_t<cached_thread> x); operator detail::thread_move_t<cached_thread>(); detail::thread_move_t<cached_thread> move(); void swap(cached_thread& x); // ... } The destructor has the responsability to restore the cached_thread to its cached_threader pool. _____________________ Vicente Juan Botet Escriba