Annotated Ada Reference Manual (Ada 202y Draft 1) — Legal Information

C.6.5 The Package System.Atomic_Operations.Modular_Arithmetic

{AI12-0364-1} The language-defined generic package System.Atomic_Operations.Modular_Arithmetic provides operations to perform arithmetic atomically on objects of modular types.

Static Semantics

2/5

{AI12-0364-1} The generic library package System.Atomic_Operations.Modular_Arithmetic has the following declaration:

3/5

generic
type Atomic_Type is mod <> with Atomic;
package System.Atomic_Operations.Modular_Arithmetic
with Pure, Nonblocking is

4/5

   procedure Atomic_Add (Item  : aliased in out Atomic_Type;
                         Value : Atomic_Type)
      with Convention => Intrinsic;

5/5

   procedure Atomic_Subtract (Item  : aliased in out Atomic_Type;
                              Value : Atomic_Type)
      with Convention => Intrinsic;

6/5

   function Atomic_Fetch_And_Add
     (Item  : aliased in out Atomic_Type;
      Value : Atomic_Type) return Atomic_Type
      with Convention => Intrinsic;

7/5

   function Atomic_Fetch_And_Subtract
     (Item  : aliased in out Atomic_Type;
      Value : Atomic_Type) return Atomic_Type
      with Convention => Intrinsic;

8/5

function Is_Lock_Free (Item : aliased Atomic_Type) return Boolean
with Convention => Intrinsic;

9/5

end System.Atomic_Operations.Modular_Arithmetic;

10/5

{AI12-0364-1} The operations of this package are defined as follows:

11/5

procedure Atomic_Add (Item  : aliased in out Atomic_Type;
                      Value : Atomic_Type)
   with Convention => Intrinsic;

12/5

{AI12-0364-1} Atomically performs: Item := Item + Value;

13/5

procedure Atomic_Subtract (Item  : aliased in out Atomic_Type;
                           Value : Atomic_Type)
   with Convention => Intrinsic;

14/5

{AI12-0364-1} Atomically performs: Item := Item - Value;

15/5

function Atomic_Fetch_And_Add
  (Item  : aliased in out Atomic_Type;
   Value : Atomic_Type) return Atomic_Type
   with Convention => Intrinsic;

16/5

{AI12-0364-1} Atomically performs: Tmp := Item; Item := Item + Value; return Tmp;

17/5

function Atomic_Fetch_And_Subtract
  (Item  : aliased in out Atomic_Type;
   Value : Atomic_Type) return Atomic_Type
   with Convention => Intrinsic;

18/5

{AI12-0364-1} Atomically performs: Tmp := Item; Item := Item - Value; return Tmp;

Extensions to Ada 2012

18.a/5

{AI12-0364-1} This package is new.

Ada 2005 and 2012 Editions sponsored in part by Ada-Europe