gcc/ada/s-purexc.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --               S Y S T E M . P U R E _ E X C E P T I O N S                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --           Copyright (C) 2000-2002 Ada Core Technologies, Inc.            --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package provides an interface for raising predefined exceptions
  35 --  with an exception message. It can be used from Pure units. This unit
  36 --  is for internal use only, it is not generally available to applications.
  37
  38 package System.Pure_Exceptions is
  39 pragma Pure (Pure_Exceptions);
  40
  41    type Exception_Type is limited null record;
  42    --  Type used to specify which exception to raise
  43
  44    --  Really Exception_Type is Exception_Id, but Exception_Id can't be
  45    --  used directly since it is declared in the non-pure unit Ada.Exceptions,
  46
  47    --  Exception_Id is in fact simply a pointer to the type Exception_Data
  48    --  declared in System.Standard_Library (which is also non-pure). So what
  49    --  we do is to define it here as a by reference type (any by reference
  50    --  type would do), and then Import the definitions from Standard_Library.
  51    --  Since this is a by reference type, these will be passed by reference,
  52    --  which has the same effect as passing a pointer.
  53
  54    --  This type is not private because keeping it by reference would require
  55    --  defining it in a way (e.g a tagged type) that would drag other run time
  56    --  files, which is unwanted in the case of e.g ravenscar where we want to
  57    --  minimize the number of run time files needed by default.
  58
  59    CE : constant Exception_Type;  -- Constraint_Error
  60    PE : constant Exception_Type;  -- Program_Error
  61    SE : constant Exception_Type;  -- Storage_Error
  62    TE : constant Exception_Type;  -- Tasking_Error
  63    --  One of these constants is used in the call to specify the exception
  64
  65    procedure Raise_Exception (E : Exception_Type; Message : String);
  66    pragma Import (Ada, Raise_Exception, "__gnat_raise_exception");
  67    pragma No_Return (Raise_Exception);
  68    --  Raise specified exception with specified message
  69
  70 private
  71    pragma Import (C, CE, "constraint_error");
  72    pragma Import (C, PE, "program_error");
  73    pragma Import (C, SE, "storage_error");
  74    pragma Import (C, TE, "tasking_error");
  75    --  References to the exception structures in the standard library
  76
  77 end System.Pure_Exceptions;