The impact of High Performance View Passing on Gen component action blocks implemented as stubs

Document ID : KB000026302
Last Modified Date : 14/02/2018
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Summary:

It is sometimes the practice to implement Gen component action blocks as stubs in the consuming model, rather than the more usual method of external action blocks.

This document describes the impact of High Performance View Passing on each of those implementation types.

Instructions:

If a Gen component action block is implemented as an external action block in the consuming model, then the only valid option is to have the High Performance View Passing (HPVP)flag set to ON in both the consuming and implementation models. The reason for this is as follows:

GLOBDATA will always be generated in the implementation model (where the action block is a normal action block), irrespective of whether the HPVP flag is ON or OFF.

However GLOBDATA will only be generated for the external action block in the consuming model when the HPVP flag is ON.
Therefore, the only combination which will have both a matching HPVP flag and have GLOBDATA generated in both models is when the HPVP flag is ON.

If a Gen component action block is implemented as a stub in the consuming model then, as long as the HPVP flag for each action block is set to be the same value in both the consuming and implementation models, the generated code will match across the models i.e. HPVP can be either OFF in both models or ON in both models (in this case, because the action block is a normal action block in both models, GLOBDATA will be generated in both models regardless of the HPVP setting).

Additional Information:

For further details on this subject see the following references in the CA Gen 8.5 documentation:
'z/OS Implementation Toolset User Guide': Chapter 7 'Implementing External Action Blocks'