[0/3] : C++20 P0482R6 and C2X N2653: support for char8_t, mbrtoc8(), and c8rtomb().

Message ID	d6ac90a2-7bb3-3f21-abd7-8695a1cec835@honermann.net
Headers	DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 60B763858D35 sender: tom-AT-honermann.net) with ESMTPSA id 47D912009E for <libc-alpha@sourceware.org>; Sun, 27 Feb 2022 11:53:13 -0500 (EST) Message-ID: <d6ac90a2-7bb3-3f21-abd7-8695a1cec835@honermann.net> Date: Sun, 27 Feb 2022 11:53:12 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Content-Language: en-US Subject: [PATCH 0/3]: C++20 P0482R6 and C2X N2653: support for char8_t, mbrtoc8(), and c8rtomb(). To: libc-alpha <libc-alpha@sourceware.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: list From: Tom Honermann via Libc-alpha <libc-alpha@sourceware.org> Reply-To: Tom Honermann <tom@honermann.net> Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" <libc-alpha-bounces+patchwork=sourceware.org@sourceware.org>

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Subject: [PATCH 0/3]: C++20 P0482R6 and C2X N2653: support for char8_t,
 mbrtoc8(), and c8rtomb().
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Tom Honermann Feb. 27, 2022, 4:53 p.m. UTC

  This series of patches provides the following:
- A fix for bug 25744 [1].
- Implementations of the mbrtoc8 and c8rtomb functions adopted for
   C++20 via WG21 P0482R6 [2] and for C2X via WG14 N2653 [3].
- A char8_t typedef as adopted for C2X via WG14 N2653 [3].

These patches addresses feedback provided in response to a previous 
submission [4].

Patch 1: A fix and test for bug 25744 [1].
Patch 2: Definitions of the mbrtoc8 and c8rtomb functions and the
          char8_t typedef.
Patch 3: Tests for the mbrtoc8 and c8rtomb functions and the char8_t
          typedef.

The fix for bug 25744 [1] is included in this patch series because the 
tests for mbrtoc8 and c8rtomb depend on it for exercising the special 
case where a pair of Unicode code points is converted to/from a single 
double byte sequence. Such conversion cases exist for Big5-HKSCS.

N2653 was adopted by WG14 for C2X during their recent meeting. This 
patch series enables the new declarations in C2X mode and when 
_GNU_SOURCE is defined.

Thank you to Joseph Myers and Carlos O'Donell for their prior reviews of 
this patch series.

Tom.

[1]: Bug 25744
      "mbrtowc with Big5-HKSCS returns 2 instead of 1 when consuming the
      second byte of certain double byte characters"
      https://sourceware.org/bugzilla/show_bug.cgi?id=25744

[2]: WG21 P0482R6
      "char8_t: A type for UTF-8 characters and strings (Revision 6)"
      https://wg21.link/p0482r6

[3]: WG14 N2653
      "char8_t: A type for UTF-8 characters and strings (Revision 1)"
      http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2653.htm

[4]: "[PATCH 2/3]: C++20 P0482R6 and C2X N2653: Implement mbrtoc8,
      c8rtomb, char8_t"
      https://sourceware.org/pipermail/libc-alpha/2022-February/136558.html