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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) 1992-2014, 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. --
-- --
------------------------------------------------------------------------------
-- This is the body of this package using POSIX barriers
with Interfaces.C; use Interfaces.C;
package body Ada.Synchronous_Barriers is
--------------------
-- POSIX barriers --
--------------------
function pthread_barrier_init
(barrier : not null access pthread_barrier_t;
attr : System.Address := System.Null_Address;
count : unsigned) return int;
pragma Import (C, pthread_barrier_init, "pthread_barrier_init");
-- Initialize barrier with the attributes in attr. The barrier is opened
-- when count waiters arrived. If attr is null the default barrier
-- attributes are used.
function pthread_barrier_destroy
(barrier : not null access pthread_barrier_t) return int;
pragma Import (C, pthread_barrier_destroy, "pthread_barrier_destroy");
-- Destroy a previously dynamically initialized barrier
function pthread_barrier_wait
(barrier : not null access pthread_barrier_t) return int;
pragma Import (C, pthread_barrier_wait, "pthread_barrier_wait");
-- Wait on barrier
--------------
-- Finalize --
--------------
overriding procedure Finalize (Barrier : in out Synchronous_Barrier) is
Result : int;
begin
Result := pthread_barrier_destroy (Barrier.POSIX_Barrier'Access);
pragma Assert (Result = 0);
end Finalize;
overriding procedure Initialize (Barrier : in out Synchronous_Barrier) is
Result : int;
begin
Result :=
pthread_barrier_init
(barrier => Barrier.POSIX_Barrier'Access,
attr => System.Null_Address,
count => unsigned (Barrier.Release_Threshold));
pragma Assert (Result = 0);
end Initialize;
----------------------
-- Wait_For_Release --
----------------------
procedure Wait_For_Release
(The_Barrier : in out Synchronous_Barrier;
Notified : out Boolean)
is
Result : int;
PTHREAD_BARRIER_SERIAL_THREAD : constant := -1;
-- Value used to indicate the task which receives the notification for
-- the barrier open.
begin
Result :=
pthread_barrier_wait
(barrier => The_Barrier.POSIX_Barrier'Access);
pragma Assert
(Result = 0 or else Result = PTHREAD_BARRIER_SERIAL_THREAD);
Notified := (Result = PTHREAD_BARRIER_SERIAL_THREAD);
end Wait_For_Release;
end Ada.Synchronous_Barriers;