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### 3257. Missing feature testing macro update from P0858

Section: 17.3.1 [support.limits.general] Status: C++20 Submitter: Antony Polukhin Opened: 2019-08-14 Last modified: 2021-02-25

Priority: 0

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Discussion:

P0858 "Constexpr iterator requirements" suggested to update the feature-testing macros `__cpp_lib_string_view` and `__cpp_lib_array_constexpr` to the date of adoption.

That did not happen.

[2019-09-02 Issue Prioritization]

Status to Tentatively Ready and priority to 0 after five positive votes on the reflector.

Proposed resolution:

This wording is relative to N4830.

1. Modify the Table 36 "Standard library feature-test macros" [tab:support.ft] in 17.3.1 [support.limits.general] as indicated:

   > Table 36: Standard library feature-test macros [tab:support.ft]
   > Macro name | Value | Header(s)
   > --- | --- | ---
   > `[…]`
   > `__cpp_lib_array_constexpr` | `2016803L` | `<iterator> <array>`
   > `[…]`
   > `__cpp_lib_string_view` | `201606803L` | `<string> <string_view>`
   > `[…]`