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) 2000-2009, Free Software Foundation, 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 3,  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.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This package provides an interface for raising predefined exceptions with
33--  an exception message. It can be used from Pure units. This unit is for
34--  internal use only, it is not generally available to applications.
35
36pragma Compiler_Unit;
37
38package System.Pure_Exceptions is
39   pragma Pure;
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
70private
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
77end System.Pure_Exceptions;
78