Re: [boost] [interprocess] basic_multiallocation_iterator, operator * and -> question

From: Steven Watanabe (steven_at_[hidden])
Date: 2007-10-27 17:06:38

AMDG

Ion Gaztañaga <igaztanaga <at> gmail.com> writes:

> You are right. I'm returning the address of a temporary! I think 
> conceptually the iterator is wrong. I should return char & for 
> operator*() instead of char *. char *should be returned by operator->.
> 
> However this makes the code uglier:
> 
> multiallocation_iterator it = ...
> 
> for(...)
>     //placement new
>     new(&*it++) T();
> 
> instead of
> 
> for(...)
>     //placement new
>     new(*it++) T();
> 
> If I want basic_multiallocation_iterator to be a well-formed iterator I 
> need to define operator->() so I think I'll need to change the interface 
> of this class (I doubt anyone is using it). Give me some time to change 
> it and pass the tests again.

It isn't /necessary/.

template<class T, class pointer>
struct arrow_proxy {
    arrow_proxy(const T& t) : impl(t) {}
    pointer operator->() const { return(&impl); }
    T impl;
}

arrow_proxy<value_type, pointer> operator->() {
    return(arrow_proxy<value_type, pointer>(**this));
}

In Christ,
Steven Watanabe