Re: [Boost-users] boost::exception_detail::error_info_base does not have virtual destructor

Subject: Re: [Boost-users] boost::exception_detail::error_info_base does not have virtual destructor
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2011-03-17 15:35:21

AMDG

On 03/17/2011 11:17 AM, Ted Byers wrote:
> I must respectfully disagree.
>
> There are two ways to look at this 'should'.  First, there is what is
> required or permitted by the standard.  Second, there is what is useful in
> managing a  software development project.  When I am trying to help my
> juniors develop good programming habits, one of the things I want them to do
> is always provide a virtual destructor whenever they make one or more member
> functions virtual.  That lets a team comprised of many more junior
> programmers than really really old guys like me avoid a lot of subtle bugs.
> And I don't see a significant down side to making a destructor virtual.
> Hence, when I am mentoring junior programmers, I routinely advise them to
> make destructors virtual whenever they need one of the other member
> functions to be virtual, whenever the issue arises.
>

a) This is in Boost. If a junior programmer
were maintaining it, this would be the
least of his worries.
b) Boost.Exception uses a different idiom
which is even more safe. i.e. use shared_ptr.
c) The virtual functions in question are
an implementation detail used in a
very restricted context. From a user's
perspective, it's a concrete class, plain
and simple.
d) Emil is strongly against changing the
code to eliminate warnings that don't
represent real problems, and prefers
suppressing them explicitly. I have
to say that I have a lot of sympathy
for his view, since beyond a certain
point, if you try to eliminate all warnings,
fixing problems turns into working
around compiler quirks. In my
experience, eliminating all warnings
on all compilers, results in less readable
and maintainable code as we dance around
all the constructs that any compiler thinks
/might/ be a problem under /some/
circumstances.

> Are you aware of a significant downside to making destructors virtual as a
> matter of habit?

Well, I almost never use virtual destructors,
because I rarely use virtual functions to begin with.

In Christ,
Steven Watanabe