1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- G N A T . E X C E P T I O N S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2000-2010, 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 an interface for raising predefined exceptions 33-- with an exception message. It can be used from Pure units. 34 35-- There is no prohibition in Ada that prevents exceptions being raised 36-- from within pure units. The raise statement is perfectly acceptable. 37 38-- However, it is not normally possible to raise an exception with a 39-- message because the routine Ada.Exceptions.Raise_Exception is not in 40-- a Pure unit. This is an annoying and unnecessary restriction and this 41-- package allows for raising the standard predefined exceptions at least. 42 43package GNAT.Exceptions is 44 pragma Pure; 45 46 type Exception_Type is limited null record; 47 -- Type used to specify which exception to raise 48 49 -- Really Exception_Type is Exception_Id, but Exception_Id can't be 50 -- used directly since it is declared in the non-pure unit Ada.Exceptions, 51 52 -- Exception_Id is in fact simply a pointer to the type Exception_Data 53 -- declared in System.Standard_Library (which is also non-pure). So what 54 -- we do is to define it here as a by reference type (any by reference 55 -- type would do), and then Import the definitions from Standard_Library. 56 -- Since this is a by reference type, these will be passed by reference, 57 -- which has the same effect as passing a pointer. 58 59 -- This type is not private because keeping it by reference would require 60 -- defining it in a way (e.g a tagged type) that would drag other run time 61 -- files, which is unwanted in the case of e.g ravenscar where we want to 62 -- minimize the number of run time files needed by default. 63 64 CE : constant Exception_Type; -- Constraint_Error 65 PE : constant Exception_Type; -- Program_Error 66 SE : constant Exception_Type; -- Storage_Error 67 TE : constant Exception_Type; -- Tasking_Error 68 -- One of these constants is used in the call to specify the exception 69 70 procedure Raise_Exception (E : Exception_Type; Message : String); 71 pragma Import (Ada, Raise_Exception, "__gnat_raise_exception"); 72 pragma No_Return (Raise_Exception); 73 -- Raise specified exception with specified message 74 75private 76 pragma Import (C, CE, "constraint_error"); 77 pragma Import (C, PE, "program_error"); 78 pragma Import (C, SE, "storage_error"); 79 pragma Import (C, TE, "tasking_error"); 80 -- References to the exception structures in the standard library 81 82end GNAT.Exceptions; 83