G++: a graphical language to specify real-time parallel applications

The G++ language belongs to the same family as Statecharts and GRAFCET. Like these languages, it is based on the state/transition model. The state and the transition concepts are presented in this paper. Temporal constraints, including timeouts and deadlines, can be expressed in G++. Like Statecharts, G++ allows a hierarchical organisation of states in two different ways: parallel decomposition (AND-state) and sequential decomposition (OR-state) of states. But G++, unlike Statecharts, also provides graphical constructs to express synchronisation and resource sharing between concurrent entities. In most applications, concurrent entities need to communicate. Communications can be built on top of the two basic interaction mechanisms. A small example (a respiration monitor) is used throughout the paper to illustrate the concepts and constructs