User`s guide

4 Stateflow 4.1 Release Notes
4-6
Upgrading from an Earlier Release
This section describes the upgrade issues involved in moving from Stateflow
4.0.2 (Release 12.0) or earlier to Stateflow 4.1 (Release 12.1).
Transition Actions into Junctions Disallowed
Transition actions are now permitted only on transitions that terminate on
states. For the following reasons, transition actions are no longer permitted on
transitions that terminate on junctions; condition actions should be used
instead:
•The semantics of transition actions for transitions into junctions are complex
and easily misunderstood and misused.
•The complex semantics of these transition actions also result in generated
code that is inefficient. Eliminating these transition actions not only
simplifies Stateflow diagrams but also results in generated code that is much
more efficient.
If your current model has these transition actions, they are flagged with an
error that refers you to Appendix D of the online Stateflow User’s Guide,
“Obsolete Features,” for a workaround. In most cases, replacing these
transition actions with condition actions gives identical chart behavior.