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Date: 16 Sep 93 06:20:30 GMT
From: mcsun!sunic!news.lth.se!dag@uunet.uu.net  (Dag Bruck)
Subject: Re: Comparison of Ada and C++ exceptions?
Message-ID: <2790je$4en@nic.lth.se>
List-Id: <comp.lang.ada>

In <comp.lang.ada> Dale Stanbrough <dale@goanna.cs.rmit.edu.au> writes:
>Recently I had reason to look at C++'s exception handling. I noticed that
>each
>exception can have associated with it some data (user defined), such as a
>string, a pointer - in fact any object the programmer wants. 

The C++ exception is an object, and I have often wanted to pass along
some information that describes the problem.  Cf. the UNIX "exception"
type that is used for problems detected in math routines.

The exception-is-an-object idea also has the benefit that you can
group exceptions by inheritance.  If you have

	class MATHERROR ....
	class OVERFLOW : public MATHERROR ....
	class ZERODIVIDE : public MATHERROR ....
	class DOMAINERROR : public MATHERROR ....

You can either decide to catch overflows separately, or any math
error, or a combination thereof:

	catch (OVERFLOW) ....
	catch (MATHERROR) ....	-- other math errors

This is quite nice.

		-- Dag