this is dangerous because it’s easy to create a dangling reference if not
consumed immediately, e.g.

template<typename T>
std::string print_vector( const vector<T> & v )
{
    const auto& stream = copy( begin(v), end(v),
ostream_iterator<int>( stringstream{}, ", " ) ).stream();
    return stream.str(); // dangling
}


On Sun, 31 Jan 2021 at 18:26, Marco Fantozzi via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> Hello,
>
> I'm new to the newsletter, so I might not be in line with standard
> netiquette here... In case please make me aware of my shortcomings, thanks
> :-)
>
>
> I noticed that it is not possible to retrieve the output stream used by a
> std::ostream_iterator,
> even if it would be useful in a few contexts like the following example:
>
> std::string print_vector( const std::vector<int> & v )
> {
> std::stringstream s;
> copy( begin(v), end(v), std::ostream_iterator<int>( s, ", " ) );
> return s.str();
> }
>
> If there was a method ostream_iterator<...>::stream() that returns the
> reference to the stream captured by the iterator,
> it would be possible to make the above code more concise:
>
> template<typename T>
> std::string print_vector( const vector<T> & v )
> {
> return copy( begin(v), end(v), ostream_iterator<int>( stringstream{},
> ", " ) ).stream().str();
> }
>
> Naturally the extension should apply to all input/output iterator facades
> in the STL
>
> Thanks
>
> --
> Trinetra
> --
> Std-Proposals mailing list
> Std-Proposals_at_[hidden]
> https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals
>