gcc/ada/g-except.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                      G N A T . E X C E P T I O N S                       --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --           Copyright (C) 2000-2001 Ada Core Technologies, Inc.            --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This package provides an interface for raising predefined exceptions
  36 --  with an exception message. It can be used from Pure units. This unit
  37 --  is for internal use only, it is not generally available to applications.
  38
  39 package GNAT.Exceptions is
  40 pragma Pure (Exceptions);
  41
  42    type Exception_Type is limited null record;
  43    --  Type used to specify which exception to raise.
  44
  45    --  Really Exception_Type is Exception_Id, but Exception_Id can't be
  46    --  used directly since it is declared in the non-pure unit Ada.Exceptions,
  47
  48    --  Exception_Id is in fact simply a pointer to the type Exception_Data
  49    --  declared in System.Standard_Library (which is also non-pure). So what
  50    --  we do is to define it here as a by reference type (any by reference
  51    --  type would do), and then Import the definitions from Standard_Library.
  52    --  Since this is a by reference type, these will be passed by reference,
  53    --  which has the same effect as passing a pointer.
  54
  55    --  This type is not private because keeping it by reference would require
  56    --  defining it in a way (e.g a tagged type) that would drag other run time
  57    --  files, which is unwanted in the case of e.g ravenscar where we want to
  58    --  minimize the number of run time files needed by default.
  59
  60    CE : constant Exception_Type;  -- Constraint_Error
  61    PE : constant Exception_Type;  -- Program_Error
  62    SE : constant Exception_Type;  -- Storage_Error
  63    TE : constant Exception_Type;  -- Tasking_Error
  64    --  One of these constants is used in the call to specify the exception
  65
  66    procedure Raise_Exception (E : Exception_Type; Message : String);
  67    pragma Import (Ada, Raise_Exception, "__gnat_raise_exception");
  68    pragma No_Return (Raise_Exception);
  69    --  Raise specified exception with specified message
  70
  71 private
  72    pragma Import (C, CE, "constraint_error");
  73    pragma Import (C, PE, "program_error");
  74    pragma Import (C, SE, "storage_error");
  75    pragma Import (C, TE, "tasking_error");
  76    --  References to the exception structures in the standard library
  77
  78 end GNAT.Exceptions;