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13.11.2 Unchecked Storage Deallocation

Unchecked storage deallocation of an object designated by a value of an access type is achieved by a call to an instance of the generic procedure Unchecked_Deallocation.
Static Semantics
The following language-defined generic library procedure exists:
          type Object(<>) is limited private;
          type Name   is access  Object;
       procedure Ada.Unchecked_Deallocation(X : in out Name);
       pragma Convention(Intrinsic, Ada.Unchecked_Deallocation);
       pragma Preelaborate(Ada.Unchecked_Deallocation);
Dynamic Semantics
Given an instance of Unchecked_Deallocation declared as follows:
       procedure Free is
           new Ada.Unchecked_Deallocation(
               object_subtype_name, access_to_variable_subtype_name);
Procedure Free has the following effect:
After Free(X), the object designated by X, and any subcomponents thereof, no longer exist; their storage can be reused for other purposes.
Bounded (Run-Time) Errors
It is a bounded error to free a discriminated, unterminated task object. The possible consequences are:
In the first two cases, the storage for the discriminants (and for any enclosing object if it is designated by an access discriminant of the task) is not reclaimed prior to task termination.
Erroneous Execution
Evaluating a name that denotes a nonexistent object is erroneous. The execution of a call to an instance of Unchecked_Deallocation is erroneous if the object was created other than by an allocator for an access type whose pool is Name'Storage_Pool.
Implementation Advice
For a standard storage pool, Free should actually reclaim the storage.


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