On May 28, 2008, at 1:25 PM, vicente.botet wrote:
----- Original Message ----- From: "Anthony Williams" <anthony.ajw@gmail.com> To: <boost@lists.boost.org> Sent: Wednesday, May 28, 2008 5:04 PM Subject: Re: [boost] "joinable"
"vicente.botet" <vicente.botet@wanadoo.fr> writes:
just a question that could clarify my thoughts, can a non joinable thread be interruptible?
No, because you no longer have a handle with which to interrupt it.
I have thought about providing an "interrupt handle" which you can obtain either from a boost::thread object, or by calling boost::this_thread::get_interrupt_handle() or similar, in which case a detached thread would be interruptible.
Ok, the question now is *should* the joinable and interruptible features of a thead be disociated? IMO they should. We can need to interrupt a thread even if we are no interested when the thread finish.
If should be better if the the implementation is possible, but I don't think that this is a big problem for the user. Most of the applications could work without releasing the resources that are released when a thread is detached, and preserv attached the thread if they want to be able to interrupt it, isn't it?
This sounds like something that should be layered on top of boost::thread, not embedded in it. boost::thread is conceptually a unique-owner situation: A single handle (boost::thread) refers to a single resource (a thread of execution). An owner should be able to do things to that resource without worrying about interference from others. If you're looking at a function with a boost::thread in it, you don't want to have to do a whole program analysis to figure out if the thing might get interrupted out from under you. thread f(thread t) { ... // is it safe to play with t in here? ... return move(t); } I'm not saying you don't need the capability of multiple interruption handles. All I'm saying is this functionality should be put into another type, like shared_future (where one expects - and knowingly pays for - ownership/control to be shared). -Howard