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------------------------------------------------------------------------------
-- --
-- GNAT LIBRARY COMPONENTS --
-- --
-- G N A T . C U R R E N T _ E X C E P T I O N --
-- --
-- S p e c --
-- --
-- Copyright (C) 1996-2004 Ada Core Technologies, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides routines for obtaining the current exception
-- information in Ada 83 style. In Ada 83, there was no official method
-- for obtaining exception information, but a number of vendors supplied
-- routines for this purpose, and this package closely approximates the
-- interfaces supplied by DEC Ada 83 and VADS Ada.
-- The routines in this package are associated with a particular exception
-- handler, and can only be called from within an exception handler. See
-- also the package GNAT.Most_Recent_Exception, which provides access to
-- the most recently raised exception, and is not limited to static calls
-- from an exception handler.
package GNAT.Current_Exception is
pragma Pure (Current_Exception);
-----------------
-- Subprograms --
-----------------
-- Note: the lower bound of returnd String values is always one.
function Exception_Information return String;
-- Returns the result of calling Ada.Exceptions.Exception_Information
-- with an argument that is the Exception_Occurrence corresponding to
-- the current exception. Returns the null string if called from outside
-- an exception handler.
function Exception_Message return String;
-- Returns the result of calling Ada.Exceptions.Exception_Message with
-- an argument that is the Exception_Occurrence corresponding to the
-- current exception. Returns the null string if called from outside an
-- exception handler.
function Exception_Name return String;
-- Returns the result of calling Ada.Exceptions.Exception_Name with
-- an argument that is the Exception_Occurrence corresponding to the
-- current exception. Returns the null string if called from outside
-- an exception handler.
-- Note: all these functions return useful information only if
-- called statically from within an exception handler, and they
-- return information about the exception corresponding to the
-- handler in which they appear. This is NOT the same as the most
-- recently raised exception. Consider the example:
-- exception
-- when Constraint_Error =>
-- begin
-- ...
-- exception
-- when Tasking_Error => ...
-- end;
--
-- -- Exception_xxx at this point returns the information about
-- -- the constraint error, not about any exception raised within
-- -- the nested block since it is the static nesting that counts.
-----------------------------------
-- Use of Library Level Renaming --
-----------------------------------
-- For greater compatibility with existing legacy software, library
-- level renaming may be used to create a function with a name matching
-- one that is in use. For example, some versions of VADS Ada provided
-- a functin called Current_Exception whose semantics was identical to
-- that of GNAT. The following library level renaming declaration:
-- with GNAT.Current_Exception;
-- function Current_Exception
-- renames GNAT.Current_Exception.Exception_Name;
-- placed in a file called current_exception.ads and compiled into the
-- application compilation environment, will make the function available
-- in a manner exactly compatible with that in VADS Ada 83.
private
pragma Import (Intrinsic, Exception_Information);
pragma Import (intrinsic, Exception_Message);
pragma Import (Intrinsic, Exception_Name);
end GNAT.Current_Exception;
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