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   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) 2002-2009, 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 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
  52 with Ada.Exceptions; use Ada.Exceptions;
  53
  54 package GNAT.Exception_Actions is
  55
  56    type Exception_Action is access
  57      procedure (Occurence : 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), and abort execution
 114    --  of the application.
 115
 116 end GNAT.Exception_Actions;