1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--              G N A T . E X C E P T I O N _ A C T I O N S                 --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2002-2012, 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 support for callbacks on exceptions
33
34--  These callbacks are called immediately when either a specific exception,
35--  or any exception, is raised, before any other actions taken by raise, in
36--  particular before any unwinding of the stack occurs.
37
38--  Callbacks for specific exceptions are registered through calls to
39--  Register_Id_Action. Here is an example of code that uses this package to
40--  automatically core dump when the exception Constraint_Error is raised.
41
42--      Register_Id_Action (Constraint_Error'Identity, Core_Dump'Access);
43
44--  Subprograms are also provided to list the currently registered exceptions,
45--  or to convert from a string to an exception id.
46
47--  This package can easily be extended, for instance to provide a callback
48--  whenever an exception matching a regular expression is raised. The idea
49--  is to register a global action, called whenever any exception is raised.
50--  Dispatching can then be done directly in this global action callback.
51
52with Ada.Exceptions; use Ada.Exceptions;
53
54package GNAT.Exception_Actions is
55
56   type Exception_Action is access
57     procedure (Occurrence : Exception_Occurrence);
58   --  General callback type whenever an exception is raised. The callback
59   --  procedure must not propagate an exception (execution of the program
60   --  is erroneous if such an exception is propagated).
61
62   procedure Register_Global_Action (Action : Exception_Action);
63   --  Action will be called whenever an exception is raised. Only one such
64   --  action can be registered at any given time, and registering a new action
65   --  will override any previous action that might have been registered.
66   --
67   --  Action is called before the exception is propagated to user's code.
68   --  If Action is null, this will in effect cancel all exception actions.
69
70   procedure Register_Id_Action
71     (Id     : Exception_Id;
72      Action : Exception_Action);
73   --  Action will be called whenever an exception of type Id is raised. Only
74   --  one such action can be registered for each exception id, and registering
75   --  a new action will override any previous action registered for this
76   --  Exception_Id. Program_Error is raised if Id is Null_Id.
77
78   function Name_To_Id (Name : String) return Exception_Id;
79   --  Convert an exception name to an exception id. Null_Id is returned
80   --  if no such exception exists. Name must be an all upper-case string,
81   --  or the exception will not be found. The exception name must be fully
82   --  qualified (but not including Standard). It is not possible to convert
83   --  an exception that is declared within an unlabeled block.
84   --
85   --  Note: All non-predefined exceptions will return Null_Id for programs
86   --  compiled with pragma Restriction (No_Exception_Registration)
87
88   function Registered_Exceptions_Count return Natural;
89   --  Return the number of exceptions that have been registered so far.
90   --  Exceptions declared locally will not appear in this list until their
91   --  block has been executed at least once.
92   --
93   --  Note: The count includes only predefined exceptions for programs
94   --  compiled with pragma Restrictions (No_Exception_Registration).
95
96   type Exception_Id_Array is array (Natural range <>) of Exception_Id;
97
98   procedure Get_Registered_Exceptions
99     (List : out Exception_Id_Array;
100      Last : out Integer);
101   --  Return the list of registered exceptions.
102   --  Last is the index in List of the last exception returned.
103   --
104   --  An exception is registered the first time the block containing its
105   --  declaration is elaborated. Exceptions defined at library-level are
106   --  therefore immediately visible, whereas exceptions declared in local
107   --  blocks will not be visible until the block is executed at least once.
108   --
109   --  Note: The list contains only the predefined exceptions if the program
110   --  is compiled with pragma Restrictions (No_Exception_Registration);
111
112   procedure Core_Dump (Occurrence : Exception_Occurrence);
113   --  Dump memory (called a core dump in some systems) if supported by the
114   --  OS (most unix systems and VMS), and abort execution of the application.
115   --  Under Windows this procedure will not dump the memory, it will only
116   --  abort execution.
117
118end GNAT.Exception_Actions;
119