> > I'll look into this idea, but some of what my processChunk() does are > > calls into an external library that I can't control so my options are > > limited there. As far as I can tell, this is an issue for any code that > > just takes > a long time. > > Yes, if this it's a call into an external API that provides no mechanism to > cancel > the call prematurely, you have no option for graceful shutdown and have to > kill the threads forcefully. > > I guess in the code handling your application exit, you can wait a little bit > for > all threads in the pool, and after an "unreasonable" > amount of time has passed (half a second?), kill them all forcefully. > Bit of a big hammer, but I don't know of any way to query for the threads > currently used by a specific ::map call (maybe someone else does though).
Yeah, and that seems to be the rub with the QtConcurrent functions, I don't get any sort of handle to the threads it is spawning off, unless maybe I can get at them via the global thread pool? I'm just starting to look at that. Other than trying to call cancel() on the associated QFutureWatcher, which does work eventually as long as your function called by map() actually returns, there doesn't seem to be a way to stop those concurrent threads. With the way my code exists at the moment, I've got the main application running in the UI thread. I intentionally spawn off Thread A and move my processingManager object over to that thread, and when that object gets a processing request, it calls QtConcurrent::map() which spawns off Threads B, C, D, etc... and I don't seem to have any control over those threads. I know when I had the infinite loop bug in my processChunk() call, killing off Thread A (the processingManager's thread) and deleting the processingManager itself didn't seem to forcefully terminate Threads B through whatever - they just kept on running forever. I'm going to try writing up a small test app to double check this. I was doing all this in the main application, which has a whole lot of other stuff going on, so maybe my issue was somewhere else... Sean This e-mail, including any attached files, may contain confidential information, privileged information and/or trade secrets for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message. _______________________________________________ Interest mailing list Interest@qt-project.org https://lists.qt-project.org/listinfo/interest
