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+------------------------------------------------------------------------------
+-- --
+-- GNAT RUN-TIME COMPONENTS --
+-- --
+-- A D A . S Y N C H R O N O U S _ B A R R I E R S --
+-- --
+-- B o d y --
+-- --
+-- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
+-- --
+-- This specification is derived from the Ada Reference Manual for use with --
+-- GNAT. The copyright notice above, and the license provisions that follow --
+-- apply solely to the contents of the part following the private keyword. --
+-- --
+-- 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- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
+-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
+-- --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception, --
+-- version 3.1, as published by the Free Software Foundation. --
+-- --
+-- You should have received a copy of the GNU General Public License and --
+-- a copy of the GCC Runtime Library Exception along with this program; --
+-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
+-- <http://www.gnu.org/licenses/>. --
+-- --
+-- GNAT was originally developed by the GNAT team at New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
+-- --
+------------------------------------------------------------------------------
+
+package body Ada.Synchronous_Barriers is
+
+ protected body Synchronous_Barrier is
+
+ -- The condition "Wait'Count = Release_Threshold" opens the barrier when
+ -- the required number of tasks is reached. The condition "Keep_Open"
+ -- leaves the barrier open while there are queued tasks. While there are
+ -- tasks in the queue no new task will be queued (no new protected
+ -- action can be started on a protected object while another protected
+ -- action on the same protected object is underway, RM 9.5.1 (4)),
+ -- guaranteeing that the barrier will remain open only for those tasks
+ -- already inside the queue when the barrier was open.
+
+ entry Wait (Notified : out Boolean)
+ when Keep_Open or else Wait'Count = Release_Threshold
+ is
+ begin
+ -- If we are executing the entry it means that the required number of
+ -- tasks have been queued in the entry. Keep_Open barrier will remain
+ -- true until all queued tasks are out.
+
+ Keep_Open := Wait'Count > 0;
+
+ -- The last released task will close the barrier and get the Notified
+ -- token.
+
+ Notified := Wait'Count = 0;
+ end Wait;
+ end Synchronous_Barrier;
+
+ ----------------------
+ -- Wait_For_Release --
+ ----------------------
+
+ procedure Wait_For_Release
+ (The_Barrier : in out Synchronous_Barrier;
+ Notified : out Boolean)
+ is
+ begin
+ The_Barrier.Wait (Notified);
+ end Wait_For_Release;
+
+end Ada.Synchronous_Barriers;