Re: [boost] Request For a feature - Templated virtual functions

Subject: Re: [boost] Request For a feature - Templated virtual functions
From: Gokulakannan Somasundaram (gokul007_at_[hidden])
Date: 2009-02-12 07:33:23

On Thu, Feb 12, 2009 at 4:00 PM, Mathias Gaunard <
mathias.gaunard_at_[hidden]> wrote:

> Gokulakannan Somasundaram wrote:
>
>  Thanks for pointing me to Boost.Variant. But let me just try to clarify my
>> understanding on Boost Variant. It is a kind of union data type, where we
>> store the data and its type together. Whenever we retrieve the data, it
>> does
>> a switch-case lookup and type-casts the data to that type. In my opinion,
>> the switch-case is equivalent to a virtual table lookup. They should be
>> having more or less the same runtime penalty.
>>
>
> Indeed.
> A switch-case is actually faster than a virtual table lookup, however.
>
>
> I did a small test in my system and the virtual function method proved to
be slightly better than using boost::variant. The difference can be ignored,
but then there is no use in switching to boost::variant. The method i
suggest is simple, it just replaces the virtual function overloading with
templates and hence it would provide better performance and better
maintenance.

Thanks,
Gokul.