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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) 1992-2005 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 2,  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.  See the GNU General Public License --
  21 -- for  more details.  You should have  received  a copy of the GNU General --
  22 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  23 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  24 -- Boston, MA 02110-1301, USA.                                              --
  25 --                                                                          --
  26 -- As a special exception,  if other files  instantiate  generics from this --
  27 -- unit, or you link  this unit with other files  to produce an executable, --
  28 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  29 -- covered  by the  GNU  General  Public  License.  This exception does not --
  30 -- however invalidate  any other reasons why  the executable file  might be --
  31 -- covered by the  GNU Public License.                                      --
  32 --                                                                          --
  33 -- GNAT was originally developed  by the GNAT team at  New York University. --
  34 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  35 --                                                                          --
  36 ------------------------------------------------------------------------------
  37
  38 generic
  39    type Object (<>) is limited private;
  40
  41 package System.Address_To_Access_Conversions is
  42    pragma Preelaborate;
  43    pragma Elaborate_Body;
  44    --  This pragma Elaborate_Body is there to ensure the requirement of what is
  45    --  at the moment a dummy null body. The reason this null body is there is
  46    --  that we used to have a real body, and it causes bootstrap problems with
  47    --  old compilers if we try to remove the corresponding file.
  48
  49    pragma Compile_Time_Warning
  50      (Object'Unconstrained_Array,
  51       "Object is unconstrained array type" & ASCII.LF &
  52       "To_Pointer results may not have bounds");
  53
  54    --  Capture constrained status, suppressing warnings, since this is
  55    --  an obsolescent feature to use Constrained in this way (RM J.4).
  56
  57    pragma Warnings (Off);
  58    Xyz : Boolean := Object'Constrained;
  59    pragma Warnings (On);
  60
  61    type Object_Pointer is access all Object;
  62    for Object_Pointer'Size use Standard'Address_Size;
  63
  64    pragma No_Strict_Aliasing (Object_Pointer);
  65    --  Strictly speaking, this routine should not be used to generate pointers
  66    --  to other than proper values of the proper type, but in practice, this
  67    --  is done all the time. This pragma stops the compiler from doing some
  68    --  optimizations that may cause unexpected results based on the assumption
  69    --  of no strict aliasing.
  70
  71    function To_Pointer (Value : Address)        return Object_Pointer;
  72    function To_Address (Value : Object_Pointer) return Address;
  73
  74    pragma Import (Intrinsic, To_Pointer);
  75    pragma Import (Intrinsic, To_Address);
  76
  77 end System.Address_To_Access_Conversions;