can a multithread program still be running after killing it in system monitor

Is it possible that a program which does not kill its threads properly before exiting still be running some piece of code somewhere even though it has been killed in system monitor? I am running ubuntu in a 开发者_开发技巧non virtual environment. My application is made with QT, it contains QThreads, a main thread and concurent functions.

If you kill the process then you kill all its threads. The only cause for concern would be if your application had spawned multiple processes - if that is the case then you may still have code executing on the machine.

This is all very speculative though as I don't know what operating system you code is running on, whether or not your application runs in a virtual environment, etc. Environment-specific factors are very relevant to the discussion, can you share a bit more about your application?

It is not possible, all modern heaviliy used operating systems manage these resources quite tightly. Threads cannot run without a process... They are all brantches from the original thread.

I don't know of any OS that doesn't fully terminate all it's threads when you kill the processes, it's possible to spawn child processes that live on after the main process has exited but in the case of threads i'd say it's not possible.