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Check state activity in Stateflow



in(state_name) returns 1 (true) if the state state_name is active. Otherwise, the operator returns 0 (false).


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Set the value of airflow to the number of fans that are turned on.

airflow = in(FAN1.On) + in(FAN2.On);

Stateflow chart that uses the in operator in a state.


To determine the state activity, a Stateflow® chart performs a localized search of the state hierarchy. The chart does not perform an exhaustive search for all states and does not stop after finding the first match. To improve the chances of finding a unique search result:

  • Use dot notation to qualify the name of the state.

  • Give states unique names.

  • Use states and boxes as enclosures to limit the scope of the path resolution search.

Additionally, a chart cannot use the in condition to trigger actions based on the activity of states in other charts.

For more information, see Resolution of State Activity.

Introduced before R2006a