The system unit System.Atomic_Counters which provides an atomic
counter type, along with increment, decrement and test operations,
available to user programs.
Tested on x86_64-pc-linux-gnu, committed on trunk
2014-10-17 Robert Dewar <de...@adacore.com>
* gnat_rm.texi: Document System.Atomic_Counters.
* impunit.adb: Add System.Atomic_Counters (s-atocou.ads) to the
list of user- accessible units added as children of System.
* s-atocou.ads: Update comment.
Index: gnat_rm.texi
===================================================================
--- gnat_rm.texi (revision 216367)
+++ gnat_rm.texi (working copy)
@@ -661,6 +661,7 @@
* Interfaces.VxWorks.IO (i-vxwoio.ads)::
* System.Address_Image (s-addima.ads)::
* System.Assertions (s-assert.ads)::
+* System.Atomic_Counters (s-atocou.ads)::
* System.Memory (s-memory.ads)::
* System.Multiprocessors (s-multip.ads)::
* System.Multiprocessors.Dispatching_Domains (s-mudido.ads)::
@@ -19074,6 +19075,7 @@
* Interfaces.VxWorks.IO (i-vxwoio.ads)::
* System.Address_Image (s-addima.ads)::
* System.Assertions (s-assert.ads)::
+* System.Atomic_Counters (s-atocou.ads)::
* System.Memory (s-memory.ads)::
* System.Multiprocessors (s-multip.ads)::
* System.Multiprocessors.Dispatching_Domains (s-mudido.ads)::
@@ -20585,6 +20587,18 @@
by an run-time assertion failure, as well as the routine that
is used internally to raise this assertion.
+@node System.Atomic_Counters (s-atocou.ads)
+@section @code{System.Atomic_Counters} (@file{s-atocou.ads})
+@cindex @code{System.Atomic_Counters} (@file{s-atocou.ads})
+
+@noindent
+This package provides the declaration of an atomic counter type,
+together with efficient routines (using hardware
+synchronization primitives) for incrementing, decrementing,
+and testing of these counters. This package is implemented
+on most targets, including all Alpha, ia64, PowerPC, SPARC V9,
+x86, and x86_64 platforms.
+
@node System.Memory (s-memory.ads)
@section @code{System.Memory} (@file{s-memory.ads})
@cindex @code{System.Memory} (@file{s-memory.ads})
Index: impunit.adb
===================================================================
--- impunit.adb (revision 216367)
+++ impunit.adb (working copy)
@@ -367,6 +367,7 @@
--------------------------------------
("s-addima", F), -- System.Address_Image
+ ("s-atocou", F), -- System.Atomic_Counters
("s-assert", F), -- System.Assertions
("s-diflio", F), -- System.Dim.Float_IO
("s-diinio", F), -- System.Dim.Integer_IO
Index: s-atocou.ads
===================================================================
--- s-atocou.ads (revision 216367)
+++ s-atocou.ads (working copy)
@@ -6,7 +6,7 @@
-- --
-- S p e c --
-- --
--- Copyright (C) 2011-2013, Free Software Foundation, Inc. --
+-- Copyright (C) 2011-2014, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
@@ -37,8 +37,6 @@
-- - all x86 platforms
-- - all x86_64 platforms
--- Why isn't this package available to application programs???
-
package System.Atomic_Counters is
pragma Preelaborate;
@@ -59,20 +57,19 @@
function Decrement (Item : in out Atomic_Counter) return Boolean;
pragma Inline_Always (Decrement);
- -- Decrements value of atomic counter, returns True when value reach zero.
+ -- Decrements value of atomic counter, returns True when value reach zero
function Is_One (Item : Atomic_Counter) return Boolean;
pragma Inline_Always (Is_One);
- -- Returns True when value of the atomic counter is one.
+ -- Returns True when value of the atomic counter is one
procedure Initialize (Item : out Atomic_Counter);
pragma Inline_Always (Initialize);
-- Initialize counter by setting its value to one. This subprogram is
- -- intended to be used in special cases when counter object can't be
+ -- intended to be used in special cases when the counter object cannot be
-- initialized in standard way.
private
-
type Unsigned_32 is mod 2 ** 32;
type Atomic_Counter is limited record
