Re: Specialization

[jimmaureenrogers@worldnet.att.net (Jim Rogers)]

"Sergey Koshcheyev" <serko84@hotmail.com> wrote in message news:<ad72e5$e9c$1@ns.felk.cvut.cz>...
> "Jim Rogers" <jimmaureenrogers@worldnet.att.net> wrote in message
> news:3CF6CF7D.8000704@worldnet.att.net...
> > Baugereau wrote:
> > > Ok so this is the difference of philosophy with STL's vector, which is
>  plain
> > > value-oriented.
> > > What I dislike here is the lack of locality of the elements, and the
>  need to
> > > "new" every time I add an element...
> > > Any comment?
> >
> > The difference is that in C++ you "new" the element before you add
> > it to the vector (in the constructor).
> 
> This is wrong, if you have a vector<BigObject> in C++ STL, then what is
> stored are BigObjects, not pointers to them. There are a few tricks that can
> be used to achieve this ("placement new", and also the fact that it is
> possible to call object destructors manually).

You got me there. My ignorant message assumed you were correct when you claimed
that the C++ STL did not need to allocate nodes in its container classes.

I have since done a little research on the web. I see that the STL container
classes do indeed allocate objects and copy them. This is clearly documented
in http://www.sgi.com/tech/stl/alloc.html 

After reading the above reference I see no significant difference between
the problems you encountered in Ada and the way the C++ STL is currently
implemented (regarding node allocation). Note that the SGI document states
that their allocator uses malloc rather than new. I am not sure this is
a big performance or safety advantage. It may be more flexible than the C++
new operator.

You clearly understand how to use the C++ STL. Have you ever implemented
the C++ STL before? I think you are only now encountering the low level
details which must exist in the C++ STL.

Jim Rogers