Ada Reference Manual (Ada 2022)
13.7.2 The Package System.Address_To_Access_Conversions
Static Semantics
The following language-defined generic library package exists:
generic
type Object(<>) is limited private;
package System.Address_To_Access_Conversions
with Preelaborate, Nonblocking, Global => in out synchronized is
type Object(<>) is limited private;
package System.Address_To_Access_Conversions
with Preelaborate, Nonblocking, Global => in out synchronized is
type Object_Pointer is access all Object;
function To_Pointer(Value : Address) return Object_Pointer
with Convention => Intrinsic;
function To_Address(Value : Object_Pointer) return Address
with Convention => Intrinsic;
function To_Pointer(Value : Address) return Object_Pointer
with Convention => Intrinsic;
function To_Address(Value : Object_Pointer) return Address
with Convention => Intrinsic;
end System.Address_To_Access_Conversions;
The To_Pointer and To_Address subprograms convert back and forth between values of types Object_Pointer and Address. To_Pointer(X'Address) is equal to X'Unchecked_Access for any X that allows Unchecked_Access. To_Pointer(Null_Address) returns null. For other addresses, the behavior is unspecified. To_Address(null) returns Null_Address. To_Address(Y), where Y /= null, returns Y.all'Address.
Implementation Permissions
An implementation may place restrictions on instantiations of Address_To_Access_Conversions.
