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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 -- S Y S T E M . A D D R E S S _ T O _ A C C E S S _ C O N V E R S I O N S  --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2009, 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 generic
  37    type Object (<>) is limited private;
  38
  39 package System.Address_To_Access_Conversions is
  40    pragma Preelaborate;
  41    pragma Elaborate_Body;
  42    --  This pragma Elaborate_Body is there to ensure the requirement of what is
  43    --  at the moment a dummy null body. The reason this null body is there is
  44    --  that we used to have a real body, and it causes bootstrap problems with
  45    --  old compilers if we try to remove the corresponding file.
  46
  47    pragma Compile_Time_Warning
  48      (Object'Unconstrained_Array,
  49       "Object is unconstrained array type" & ASCII.LF &
  50       "To_Pointer results may not have bounds");
  51
  52    --  Capture constrained status, suppressing warnings, since this is
  53    --  an obsolescent feature to use Constrained in this way (RM J.4).
  54
  55    pragma Warnings (Off);
  56    Xyz : Boolean := Object'Constrained;
  57    pragma Warnings (On);
  58
  59    type Object_Pointer is access all Object;
  60    for Object_Pointer'Size use Standard'Address_Size;
  61
  62    pragma No_Strict_Aliasing (Object_Pointer);
  63    --  Strictly speaking, this routine should not be used to generate pointers
  64    --  to other than proper values of the proper type, but in practice, this
  65    --  is done all the time. This pragma stops the compiler from doing some
  66    --  optimizations that may cause unexpected results based on the assumption
  67    --  of no strict aliasing.
  68
  69    function To_Pointer (Value : Address)        return Object_Pointer;
  70    function To_Address (Value : Object_Pointer) return Address;
  71
  72    pragma Import (Intrinsic, To_Pointer);
  73    pragma Import (Intrinsic, To_Address);
  74
  75 end System.Address_To_Access_Conversions;