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### 2826. `string_view` iterators use old wording

Section: 21.4.3.3 [string.view.iterators] Status: C++17 Submitter: Alisdair Meredith Opened: 2016-11-17 Last modified: 2017-07-30

Priority: 0

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Discussion:

The wording for `basic_string_view` was written before the definition of a contiguous iterator was added to C++17 to avoid repeating redundant wording.

Suggested modification of 21.4.3.3 [string.view.iterators] p1 (stealing words from `valarray begin`/`end`):

> -1- A constant random-access iterator type such that, for a `const_iterator it`, if `&*(it + N)` is valid, then `&*(it + N) == (&*it) + N` A type that meets the requirements of a constant random access iterator (24.2.7) and of a contiguous iterator (24.2.1) whose `value_type` is the template parameter `charT`.

[2017-01-27 Telecon]

Priority 0

Proposed resolution:

This wording is relative to N4606.

1. Modify 21.4.3.3 [string.view.iterators] as indicated:

   >     using const_iterator = implementation-defined;

   > > -1- A constant random-access iterator type such that, for a `const_iterator it`, if `&*(it + N)` is valid, then `&*(it + N) == (&*it) + N` type that meets the requirements of a constant random access iterator (23.3.5.7 [random.access.iterators]) and of a contiguous iterator (23.3.1 [iterator.requirements.general]) whose `value_type` is the template parameter `charT`.

   > > -2- For a `basic_string_view str`, any operation that invalidates a pointer in the range `[str.data(), str.data() + str.size())` invalidates pointers, iterators, and references returned from `str`'s methods.

   > > -3- All requirements on container iterators (22.2 [container.requirements]) apply to `basic_string_view::const_iterator` as well.