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12.5.4 Formal Access Types

(1)

The class determined for a formal access type is the class of all access types.

Syntax

(2)
       formal_access_type_definition ::= access_type_definition

Legality Rules

(3)

For a formal access-to-object type, the designated subtypes of the formal and actual types shall statically match.

(4)

If and only if the general_access_modifier constant applies to the formal, the actual shall be an access-to-constant type. If the general_access_modifier all applies to the formal, then the actual shall be a general access-to-variable type (see 3.10).

(5)

For a formal access-to-subprogram subtype, the designated profiles of the formal and the actual shall be mode-conformant, and the calling convention of the actual shall be protected if and only if that of the formal is protected.

Examples

(6)

Example of formal access types:

(7)
       --  the formal types of the generic package
(8)
       generic
          type Node is private;
          type Link is access Node;
       package P is
          ...
       end P;
(9)
       --  can be matched by the actual types
(10)
       type Car;
       type Car_Name is access Car;
(11)
       type Car is
          record
             Pred, Succ : Car_Name;
             Number     : License_Number;
             Owner      : Person;
          end record;
(12)
       --  in the following generic instantiation
(13)
       package R is new P(Node => Car, Link => Car_Name);

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