Control Boundaries for Activation Groups

This example shows how control boundaries are defined between activation groups.

Figure 1 shows two activation groups and the control boundaries established by the various calls. Invocations of procedures P2, P3, and P6 are potential control boundaries. For example, when you are running procedure P7, procedure P6 is the control boundary. When you are running procedures P4 or P5, procedure P3 becomes the control boundary.

Figure 1. Control Boundaries. The shaded procedures are control boundaries.

Note: Control boundaries are defined between all activation groups, including the default activation groups. For example, if a call stack entry associated with the teraspace default activation group immediately precedes a call stack entry associated with an OPM default activation group there will be a control boundary between the two call stack entries.