Need a statement of applicability.
A thread will terminate when it completes its assigned method, or when it raises an exception, or when it has been explicitly terminated (how is this done)
Joining a thread causes the joining thread to await the joined thread’s termination before continue. Useful for executing in parallel and then proceeding after the dispatched work is complete, but does not notify the joining task if the termination was premature.
In C++ 2020, methods are provided to instruct one or more threads to terminate. This is not premature termination since the requested thread terminates itself.
C++ 2020 provides callbacks in the form of stop_callback to notify the setting thread when a thread of interest has been terminated. It also provides stop_token for a thread to query it is being instructed to terminate.
Any thread can re-throw an exception to be caught by the creator of the terminating thread, (but the parent may have terminated first).
The semantics of C++ is that all children of the main program will terminate if the main program terminates. It is necessary to join the main program to all its children to ensure that children are not silently terminated prematurely.
To avoid the vulnerability or mitigate its ill effects, C++ software developers can:
Use the avoidance mechanisms of ISO/IEC 24772-1 clause 6.63.5.
Use low-level operating system primitives or other APIs where available to check that a required thread is still active.
Ensure that the main program joins all created threads that need to complete normally.