3. gen_fsm Behaviour
3 gen_fsm Behaviour
This section is to be read with the gen_fsm(3) manual page in STDLIB, where all interface functions and callback functions are described in detail.
3.1 Finite-State Machines
A Finite-State Machine (FSM) can be described as a set of relations of the form:
State(S) x Event(E) -> Actions(A), State(S')
These relations are interpreted as meaning:
If we are in state S and event E occurs, we are to perform actions A and make a transition to state S'.
For an FSM implemented using the gen_fsm behaviour, the state transition rules are written as a number of Erlang functions, which conform to the following convention:
StateName(Event, StateData) ->
