1------------------------------------------------------------------------------ 2-- -- 3-- GNAT LIBRARY COMPONENTS -- 4-- -- 5-- G N A T . C U R R E N T _ E X C E P T I O N -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1996-2010, AdaCore -- 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 routines for obtaining the current exception 33-- information in Ada 83 style. In Ada 83, there was no official method 34-- for obtaining exception information, but a number of vendors supplied 35-- routines for this purpose, and this package closely approximates the 36-- interfaces supplied by DEC Ada 83 and VADS Ada. 37 38-- The routines in this package are associated with a particular exception 39-- handler, and can only be called from within an exception handler. See 40-- also the package GNAT.Most_Recent_Exception, which provides access to 41-- the most recently raised exception, and is not limited to static calls 42-- from an exception handler. 43 44package GNAT.Current_Exception is 45 pragma Pure; 46 47 ----------------- 48 -- Subprograms -- 49 ----------------- 50 51 -- Note: the lower bound of returned String values is always one 52 53 function Exception_Information return String; 54 -- Returns the result of calling Ada.Exceptions.Exception_Information 55 -- with an argument that is the Exception_Occurrence corresponding to 56 -- the current exception. Returns the null string if called from outside 57 -- an exception handler. 58 59 function Exception_Message return String; 60 -- Returns the result of calling Ada.Exceptions.Exception_Message with 61 -- an argument that is the Exception_Occurrence corresponding to the 62 -- current exception. Returns the null string if called from outside an 63 -- exception handler. 64 65 function Exception_Name return String; 66 -- Returns the result of calling Ada.Exceptions.Exception_Name with 67 -- an argument that is the Exception_Occurrence corresponding to the 68 -- current exception. Returns the null string if called from outside 69 -- an exception handler. 70 71 -- Note: all these functions return useful information only if 72 -- called statically from within an exception handler, and they 73 -- return information about the exception corresponding to the 74 -- handler in which they appear. This is NOT the same as the most 75 -- recently raised exception. Consider the example: 76 77 -- exception 78 -- when Constraint_Error => 79 -- begin 80 -- ... 81 -- exception 82 -- when Tasking_Error => ... 83 -- end; 84 -- 85 -- -- Exception_xxx at this point returns the information about 86 -- -- the constraint error, not about any exception raised within 87 -- -- the nested block since it is the static nesting that counts. 88 89 ----------------------------------- 90 -- Use of Library Level Renaming -- 91 ----------------------------------- 92 93 -- For greater compatibility with existing legacy software, library 94 -- level renaming may be used to create a function with a name matching 95 -- one that is in use. For example, some versions of VADS Ada provided 96 -- a function called Current_Exception whose semantics was identical to 97 -- that of GNAT. The following library level renaming declaration: 98 99 -- with GNAT.Current_Exception; 100 -- function Current_Exception 101 -- renames GNAT.Current_Exception.Exception_Name; 102 103 -- placed in a file called current_exception.ads and compiled into the 104 -- application compilation environment, will make the function available 105 -- in a manner exactly compatible with that in VADS Ada 83. 106 107private 108 pragma Import (Intrinsic, Exception_Information); 109 pragma Import (intrinsic, Exception_Message); 110 pragma Import (Intrinsic, Exception_Name); 111 112end GNAT.Current_Exception; 113