Re: [boost] Is there any interest in a library that provides containers with virtual destructors?

From: Victor A. Wagner Jr. (vawjr_at_[hidden])
Date: 2005-10-25 23:35:53

At 10:04 2005-10-25, Andy Tompkins wrote:
>I have read a few times that people sometimes wish that std::vector (or
>other containers) had a virtual destructor.  I have recently wished
>for the same thing and I fairly quickly write a class called
>virtual_vector something like:
>
>template <class Type, class Allo = std::allocator<Type> >
>class virtual_vector {
>public:
>   ~virtual_vector();
>   ...
>private:
>   std::vector<Type, Alloc> m_vector;
>};
>
>All the public methods of std::vector are present in virtual_vector and
>are just forwarded on m_vector.
>
>This allows one to write something like:
>
>struct person {
>   string first_name;
>   string last_name;
>};
>class people : public virtual_vector<person>
>{
>public:
>   //extra methods
>};
>
>Is this useful?

unless I mis-read (or mis-understood...far more likely) a lot of 
books on how C++ works, I don't believe there is any reason for what 
_you've_ shown to need a virtual destructor.  Until your derived 
class needs a non-trivial destructor it won't matter one way or 
another.  Specifically, simply adding methods shouldn't create the 
need for a non-trivial destructor.

>Has this been done already?
>
>Thanks in advance for any comments?
>   Andy Tompkins
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Victor A. Wagner Jr.      http://rudbek.com
The five most dangerous words in the English language:
               "There oughta be a law"