File : 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) 2000-2013, 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 -- --
19 -- --
20 -- --
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
36 pragma Compiler_Unit_Warning;
37
38 package 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
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;