E.2.1 Shared Passive Library Units

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A shared passive library unit is used for managing global data shared between active partitions. The restrictions on shared passive library units prevent the data or tasks of one active partition from being accessible to another active partition through references implicit in objects declared in the shared passive library unit.


The form of a pragma Shared_Passive is as follows:

pragma Shared_Passive[(library_unit_name)];

Legality Rules

A shared passive library unit is a library unit to which a Shared_Passive pragma applies. The following restrictions apply to such a library unit:

  • it shall be preelaborable (see 10.2.1);
  • it shall depend semantically only upon declared pure or shared passive library units;
  • it shall not contain a library-level declaration of an access type that designates a class-wide type, task type, or protected type with entry_declarations.

Notwithstanding the definition of accessibility given in 3.10.2, the declaration of a library unit P1 is not accessible from within the declarative region of a shared passive library unit P2, unless the shared passive library unit P2 depends semantically on P1.

Static Semantics

A shared passive library unit is preelaborated.

Post-Compilation Rules

A shared passive library unit shall be assigned to at most one partition within a given program.

Notwithstanding the rule given in 10.2, a compilation unit in a given partition does not need (in the sense of 10.2) the shared passive library units on which it depends semantically to be included in that same partition; they will typically reside in separate passive partitions.

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