Talk:cpp/thread/stop source/request stop
From cppreference.com
This statement in the Notes section is not from the standard:
If the stop_source object has stop-state but a stop request has already been made, this function returns false. However there is no guarantee that another stop_source object which has just (successfully) requested stop is not still in the middle of invoking a stop_callback function.
I am not sure if it is true or not.