Re: [boost] [exception] warning about non-virtual destructor - resolution?

Subject: Re: [boost] [exception] warning about non-virtual destructor - resolution?
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2012-04-15 08:53:07

On 14/04/12 23:13, Daniel James wrote:

> In this case the warning fires because it's triggered by the delete
> command, which is not covered by the system header pragma in the
> exception headers. This is different to the old warning which was
> triggered by the destructor. This might actually be a problem for
> other libraries as well. 'checked_delete' is used by 'shared_ptr' and
> is supposed to be safe for the case when the destructor isn't virtual,
> so this might result in warnings for valid uses of 'shared_ptr'. So,
> for g++ 4.7 and up, the correct solution *might* be to use the new
> pragmas to disable the warning in checked_delete. But it might not,
> I'm not familiar enough with checked_delete to know if that would be
> appropriate.

Calling delete on a pointer to a polymorphic type with a non-virtual 
destructor might be a bug. It would be a bad idea for shared_ptr to 
disable this warning for any other type than error_info.

The simplest solution is to make the destructor of error_info virtual, 
since it doesn't add any significant overhead, especially compared to 
how bloated Boost.Exception is as a whole...

It would also have the advantage of not relying on fragile 
compiler-specific warning suppression mechanisms.

As a rule, rewriting the code so that the warning doesn't happen is much 
more valuable than disabling the warning.