Version 1.2 of ais/ai-00421.txt

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!standard H.06(01)          05-04-17 AI95-00421/02
!class amendment 05-03-28
!status work item
!status received
!priority High
!difficulty Easy
!subject Sequential activation and attachment
The mechanism of activation and attachment of handlers described in AI-265 is clarified.
The second and third paragraphs of the dynamic semantics of H.6 described in AI-265 are unclear.
(See summary.)
Replace the second and third paragraphs of the dynamic semantics section of H.6 (as defined by AI-265) with
If the partition elaboration policy is Sequential, all task activations for library-level tasks and all interrupt handler attachments for library-level interrupt handlers are deferred. The handler attachments occur after the elaboration of all library_items. Then the Environment task is suspended and all deferred activations are completed. The Environment task then calls the main program.
If any deferred task activation fails, Tasking_Error is raised in the Environment task at the beginning of the sequence of statements of the main program. If a number of dynamic interrupt handler attachments for the same interrupt are deferred then the most recent call of Attach_Handler or Exchange_Handler determines which handler is attached.
Add a new Note:
If any task activation fails the Environment task is unable to handle Tasking_Error and will become completed immediately. With the standard partition elaboration policy this exception could be handled within a library unit.
The essence of AI-265 was OK, just a bit vague. It is now clear that the sequential order is: library items, handler attachments, library task activations, main program.
None (there isn't one in AI-265, either).
!ACATS test
The ACATS test for AI-265 should cover this change, too.


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