gcc/ada/a-synbar-posix.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --             A D A . S Y N C H R O N O U S _ B A R R I E R S              --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- This specification is derived from the Ada Reference Manual for use with --
  12 -- GNAT. The copyright notice above, and the license provisions that follow --
  13 -- apply solely to the  contents of the part following the private keyword. --
  14 --                                                                          --
  15 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  16 -- terms of the  GNU General Public License as published  by the Free Soft- --
  17 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  18 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  19 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  20 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  21 --                                                                          --
  22 -- As a special exception under Section 7 of GPL version 3, you are granted --
  23 -- additional permissions described in the GCC Runtime Library Exception,   --
  24 -- version 3.1, as published by the Free Software Foundation.               --
  25 --                                                                          --
  26 -- You should have received a copy of the GNU General Public License and    --
  27 -- a copy of the GCC Runtime Library Exception along with this program;     --
  28 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  29 -- <http://www.gnu.org/licenses/>.                                          --
  30 --                                                                          --
  31 -- GNAT was originally developed  by the GNAT team at  New York University. --
  32 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This is the spec of this package using POSIX barriers
  37
  38 with System;
  39 private with Ada.Finalization;
  40 private with Interfaces.C;
  41
  42 package Ada.Synchronous_Barriers is
  43    pragma Preelaborate (Synchronous_Barriers);
  44
  45    subtype Barrier_Limit is Positive range 1 .. Positive'Last;
  46
  47    type Synchronous_Barrier (Release_Threshold : Barrier_Limit) is
  48       limited private;
  49
  50    procedure Wait_For_Release
  51      (The_Barrier : in out Synchronous_Barrier;
  52       Notified    : out Boolean);
  53
  54 private
  55    --  POSIX barrier data type
  56
  57    SIZEOF_PTHREAD_BARRIER_T : constant :=
  58      (if System.Word_Size = 64 then 32 else 20);
  59    --  Value defined according to the linux definition in pthreadtypes.h. On
  60    --  other system, e.g. MIPS IRIX, the object is smaller, so it works
  61    --  correctly although we are wasting some space.
  62
  63    type pthread_barrier_t_view is (size_based, align_based);
  64
  65    type pthread_barrier_t (Kind : pthread_barrier_t_view := size_based) is
  66       record
  67          case Kind is
  68             when size_based =>
  69                size : Interfaces.C.char_array (1 .. SIZEOF_PTHREAD_BARRIER_T);
  70             when align_based =>
  71                align : Interfaces.C.long;
  72          end case;
  73       end record;
  74    pragma Unchecked_Union (pthread_barrier_t);
  75
  76    type Synchronous_Barrier (Release_Threshold : Barrier_Limit) is
  77      new Ada.Finalization.Limited_Controlled with
  78         record
  79            POSIX_Barrier : aliased pthread_barrier_t;
  80         end record;
  81
  82    overriding procedure Initialize (Barrier : in out Synchronous_Barrier);
  83    overriding procedure Finalize   (Barrier : in out Synchronous_Barrier);
  84 end Ada.Synchronous_Barriers;