How to make the main thread wait till all other qthread?
Without an event loop and signals/slots, Qt threads don’t have a join () method, found in other threading implementation, but QThread::wait () is somewhat similar. The thread associated with this QThread object has finished execution (i.e. when it returns from QThread::run () ). This function will return true if the thread has finished.
How is a thread kept alive without spinning in a while loop?
The thread would typically wait on one of these objects being “signalled”, with these objects being signalled from something like an interrupt, or even another thread. But the principle is the same – the thread blocks as much as possible when it has no data to process so it does not waste CPU cycles spinning idly.
When does a thread put itself to sleep?
If no data is available, it actively puts itself to sleep for 5ms. This causes the scheduler to change this thread to the “waiting” state, and perform a context switch to another thread that is “ready to run”.
When does the main thread exit the program?
Execution begins sequentially one line at a time (jumping to other functions if they are called, and returning when they end). In the above example, the program will eventually exit. Now typically in an embedded system the main thread will typically not (or at least probably shouldn’t) exit:
If no data is available, it actively puts itself to sleep for 5ms. This causes the scheduler to change this thread to the “waiting” state, and perform a context switch to another thread that is “ready to run”.
The thread would typically wait on one of these objects being “signalled”, with these objects being signalled from something like an interrupt, or even another thread. But the principle is the same – the thread blocks as much as possible when it has no data to process so it does not waste CPU cycles spinning idly.
How to determine when a thread is in the running state?
Although I’m having a bit of trouble (probably too rusty with C++) determining when the Thread is in the Running state via get_state (), I did printf the State of the Thread in various scenarios. Here is what I have seen: Thread state is Running (1) after creation, then is WaitingMailbox (8) during while (1) loop
Execution begins sequentially one line at a time (jumping to other functions if they are called, and returning when they end). In the above example, the program will eventually exit. Now typically in an embedded system the main thread will typically not (or at least probably shouldn’t) exit: