Re: void pointer and map (fwd)

[Anitha Boyapati <anithab at sankhya dot com>]

On Fri, 21 Dec 2007, Ted Byers wrote:

> 
> First, I don't see the point of reinterpret cast here,
> or even use of a void pointer.  Unless this is a
> really dumbed down example, you probably ought to
> think about the types you'll be using for this.

It is really a badly tailored version of a bigger problem.
Actually, it all boils down to usage of types. With "Value", I need to 
able to represent both C++ data types (int, long, long long) as well as 
some of the user defined data types. Previously, I used a union for built 
in types and objects of user defined types  packed into Value. Now that 
gave me a performance hit.(Everytime a Value is initialised, all the 
constructors of user defined types have to be gone through unnecessarily 
while an instance of Value reprensents only one of the types) It was 
really slow. So came a void pointer and a reinterpret cast along with it.

I have one more question : Now that my code is heavily loaded with 
reinterpret_cast, does this have a performance problem ? In short, 
does exhaustive usage of reinterpret_cast hinder performance ? 
That will be good to know.

> 
> Second, why use a naked pointer instead of a smart
> pointer (such as that found in boost)?  You can use

This is something I was unaware of. Maybe I will give it a try.

> the latter wherever you'd be tempted to use a naked
> pointer, and it becomes all the easier to avoid the
> sort of problem you posted about.  With a smart
> pointer, you could even get rid of the destructor
> without losing anything, unless you need to make it
> virtual, should there be a chance another class could
> be derived from Value, which has a need for a
> non-trivial destructor.

 Nothing virtual in the structure. Thanks!
> 
> HTH
> 
> Ted
> 

-- 
Regards,
Anitha B
@S A N K H Y A