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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;
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