Re: exceptions in destructors

From:
"Alf P. Steinbach" <alfps@start.no>
Newsgroups:
comp.lang.c++.moderated
Date:
Tue, 18 Aug 2009 03:48:42 CST
Message-ID:
<h6ap62$k8u$1@news.eternal-september.org>
* Pete Becker:

Alf P. Steinbach wrote:

* Pete Becker:

Ron wrote:

On Aug 15, 8:12 am, Brendan <catph...@catphive.net> wrote:

   Foo foo();


This doesn't create an object. It declares a function called foo
that returns a Foo.

Try it again with:
     Foo foo;


Same result, right?


What I actually said, before the misleading snippage, was:

    Same result, right? Good catch, though. <g>


I apologize for quoting only the question and not the praise of Ron and the
following emoticon.

In my defense, I didn't realize that snipping the praise and following emoticon,
  could be misleading.

Also in my defense, but this may reflect badly on me, I still fail to see any
misleading impression that snipping the praise and emoticon could give (in
particular since that, as I understand it, wasn't relevant to my article)?

I wasn't looking for an explanation of why it was the same. Especially
not this one:

Yes.

The original example was ...

  struct Foo {
     ~Foo() {
       try {
         throw exception();
       } catch (exception e) {
       }
     }
  };

... and as you can see neither the Foo constructor nor its destructor
has any side-effect.


This is quite misleading, since side effects (other than exiting or
throwing exceptions), even if they were present, wouldn't affect the
exception handling in the original example.


The explanation I gave, quoted in full above, about why defining an automatic
Foo object (instead of declaring a routine) doesn't affect the observable
behavior, is both correct and complete, and not at all misleading.

Excluding from consideration, from the meaning of "side-effect", those that can
affect the program's behavior, one must however conclude, as you do, that the
remaining possible side-effects can't affect the program's behavior.

To the degree that the wording in the paragraph quoted above makes that absurd
assumption seem less than completely absurd, *it* is misleading; sorry.

Cheers & hth.,

- Alf

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