Re: Basic C++ question

[Lars Gullik Bjønnes]

Baruch Even <[EMAIL PROTECTED]> writes:

| On Fri, 20 Oct 2000, Lior Silberman wrote:
| 
| > I know this _feels_ bad, but I think the most efficient implementation
| > will be to handle the temporary ourselves:
| > 
| > Menu* Menu::expand (Buffer* buf)
| >     {
| >     Menu *resulting_menu = new Menu();
| >     ...
| >     // add stuff to the new menu
| >     ...
| >     return resulting_menu;
| >     }
| > 
| > Which can be used as:
| > 
| > Menu *tmp = menu.expand();
| > ...
| > ...
| > delete tmp;
| 
| At least if we go this way we should use auto_ptr<Menu> as in:
| {
|    auto_ptr<Menu> tmp( menu.expand() );
|    ...
|    ...
| }
| 
| This is also better since we reduce the risk of exceptions and/or returns
| before the delete.

If we want to do this exception safe we have to do something like:

build_men(Menu & m) {
        Menu me;
        ...; // populate me
        m.swap(me);
}

to avoid half populated objects, and objects in unknown state.

        Lgb