Root state

Every statechart has a root state, which is the initial state of the statechart. The initial transition leads from the (invisible) root state directly into the state that is the target of the initial transition when the object starts its behavior.

A <state>_active pointer is generated for every component state of an And state. This member is the low‑level active state (leaf state) used for taking events. The received event first tries to be consumed by the <state>_active state. If it cannot, it then tries to be consumed by the parent.

A <state>_subState pointer is generated for each Or state (parent state). This member is the active child state in the parent. It is used for exiting from the parent state. When the parent state exits, its active child state also exits.

By default, the root state is both a component state and an Or state. Therefore, both rootState_subState and rootState_active members are generated for it in the object.