On 20 Oct 2000, Jean-Marc Lasgouttes wrote:
>
> The method Menu::expand in Menubackend.C has the following signature:
>
> /// Expands some special entries of the menu
> /** The entries with the following kind are exanded to a
> sequence of Command MenuItems: Lastfiles, Documents,
> ViewFormats, ExportFormats, UpdateFormats
> */
> void expand(Menu & tomenu, Buffer *) const;
>
> It would have been more reasonable to have something like
> Menu const expand(Buffer *) const;
>
> The reason I did not do it is that I was not sure what would happen:
> if you create a temporary object in a function, and return it at the
> end, is the object copied or do you return it without copy? This can
> have some importance if the object is a big vector (think 'table of
> contents').
>
> So what is the right way to return this kind of big objects?
If it's a large object that has long c-tor time the best method is to
return a const refernce as in: Menu const & expand(Buffer *) const;
This will make sure that a copy will only occur when it's really
necessary, and the object can still be used again as in:
menu.expand( ).shrink( )
That's the general idea, I've no idea how Menu::expand works currently.
--
Baruch Even
http://techst02.technion.ac.il/~sbaruch/ (My Site)
http://www.redrival.com/jindor/ (My brothers AD&D site)
" Learn to laugh ... it's the path to true love! "
- The Angel in the movie Michael
