Re: is such exception handling approach good?

From:

"Ben Voigt [C++ MVP]" <rbv@nospam.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Wed, 26 Dec 2007 09:06:45 -0600

Message-ID:

<etWJ1C9RIHA.5404@TK2MSFTNGP03.phx.gbl>

"George" <George@discussions.microsoft.com> wrote in message
news:0E97223C-EC26-4D82-A277-C8FD589BD67D@microsoft.com...

Thanks Ben,

Actually, any try-finally block *can* be expressed as RAII. The term
"smart
pointer" may not be applicable if the resource isn't memory, but the same
technique works.

I agree that smart pointer could only works for memory, other types of
resources can not utilize it. But what do you mean same technique? You
mean
you have some ways to let smart pointer work for resources other than
memory?

The technique is

One C++ object for each resource instance that needs to be freed.
Free that resource in the destructor.
Compose these objects to make more complicated objects that require multiple
resources, but now needn't worry about freeing them (because C++
automatically calls base and member destructors).

regards,
George

"Ben Voigt [C++ MVP]" wrote:

"ajk" <ak@workmail.com> wrote in message
news:ddism3hhe474amlfoevcohcgbf6m2oe2bq@4ax.com...

On Sat, 22 Dec 2007 20:05:33 -0500, "Larry Smith"
<no_spam@_nospam.com> wrote:

so your requirement is that all member variables must be smart
pointers? not that great.

Actually it is. It promotes encapsulation of resources and it's very
clean
compared to your "Init()" alternative. Someone earlier mentioned
appendix
E
of Stroustrup's book. He himself shoots your technique down.

what i mean is that not all can expressed as smart pointers, nm but
quoting instead of thinking yourself I suppose it is no point in
continuing this discussion. merry xmas

Actually, any try-finally block *can* be expressed as RAII. The term
"smart
pointer" may not be applicable if the resource isn't memory, but the same
technique works.