Hi Boost::signals are not thread-safe http://boost.org/doc/html/signals/s04.html#id2738867 "Boost.Signals will support thread safety in the future." I would like to know when this feature will be implemented, if somebody is working on it. I like very much the fact that Qt slot/signals are thread safe, it helps really a *lot* : "the slot is invoked when control returns to the event loop of the thread to which the object belongs. The slot is executed in the thread where the receiver object lives." http://doc.trolltech.com/4.1/threads.html Do you plan also to make Boost::signals executed in the thread where the receive object lives? Thanks in advance for your answers Regards, -- Tanguy Krotoff <tanguy.krotoff@wengo.fr> http://openwengo.org