Why is there no std :: make_raw_storage_iterator?
I'm wondering why it std::raw_storage_iterator
doesn't have companions std::make_raw_storage_iterator
like std::move_iterator
and std::make_move_iterator
. The class template std::raw_storage_iterator
has two template parameters. So I think it is actually more useful to provide a make function for std::raw_storage_iterator
than std::move_iterator
that only has to specify one template parameter.
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With @ dyps suggestions, a sane implementation is indeed possible:
template <typename OutputIt>
auto make_raw_storage_iterator( OutputIt out ) {
return std::raw_storage_iterator<OutputIt, std::remove_pointer_t<decltype(&*out)>>(out);
}
( Demo with example cppreference)
This is guaranteed to work with §20.7.10 / 1, which imposes requirements on template arguments raw_storage_iterator
, requires:
OutputIterator
is required to beoperator*
returned by the object for which it isoperator&
defined and returns a pointer toT
[..]
Where T
is the second argument, the type of the output range value. Thus, given the underlying output iterator, we have sufficient information to determine the intended specialization raw_storage_iterator
.
The reason this was not suggested is undoubtedly nothing more than an oversight - consider that make_reverse_iterator
or make_unique
not even were provided prior to C ++ 14. Feel free to take the first step.
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