Chapter 21
Events and Signals
In the real world, things happen. Not only do things happen, but lots of things may happen at the same time, and at the most unexpected times. “Things that happen” are called events, and each one represents the specification of a significant occurrence that has a location in time and space.
In the context of state machines, you use events to model the occurrence of a stimulus that can trigger a state transition. Events may include signals, calls, the passing of time, or a change in state.
Events may be synchronous or asynchronous, so modeling ...
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