P1944 Add Constexpr Modifiers to Functions in cstring and cwchar Headers

[wg21bot]

P1944R0 Add Constexpr Modifiers to Functions in cstring and cwchar Headers (Daniil Goncharov, Antony Polukhin)

[brycelelbach]

Prague 2020-02 LEWGI Minutes

P1944R0 constexpr <cstring> and <cwchar>: Direction Review

Chair: Fabio Fracassi

Champion: Antony Polukhin

Minute Taker: Ben Craig

Start Review: 2020-02-13 09:16

Changing the definition of <cstuff> from namespace std { using ::stuff; } to defining our own version in <cstuff>

Start Polling: 09:28

POLL: We think this is important enough that we want to spend more time on this problem.

Strongly For	Weakly For	Neutral	Weakly Against	Strongly Against
8	6	1	1	0

Attendance: 19

# of Authors: 1

Author Position: SF

A: I don't think we should be using C interfaces like this.

That has strong consensus.

POLL: We want to add std::strtok(char*, char*, char**).

Strongly For	Weakly For	Neutral	Weakly Against	Strongly Against
2	4	5	4	0

Attendance: 19

# of Authors: 1

Author Position: N

That has no consensus.

Find the prior discussions on adding constexpr to <cstuff> headers, consult implementors, and add what you learn to the next revision.

Consult SG16 on this paper regarding locales.

End: 09:36

CONSENSUS: Bring a revision of P1944R0 (constexpr <cstring> and <cwchar>), with the guidance below, to LEWGI for further design review.

• Remove std::strtok(char*, char*, char**).
• Find the prior discussions on adding constexpr to <cstuff> headers, consult implementors, and add what you learn to the next revision.
• Consult SG16 on this paper regarding locales.

[wg21bot]

P1944R1 Add Constexpr Modifiers to Functions in cstring and cwchar Headers (Daniil Goncharov, Antony Polukhin)

[cor3ntin]

Mailing list review 5-19 October 2020

• We want to see at least one implementation in a standard library

• The paper should mention of and

• Do we need all of these functions? Is our time not better spent on improving higher level facilities? Some of these higher level facilities may need these C functions

• Author note that some of these functions are constant evaluated in clang https://releases.llvm.org/5.0.1/tools/clang/docs/LanguageExtensions.html#string-builtins - ditto for GCC but there are corner cases where it doesn't work

• This proposal for some implementations requires changing either the lib c or the compiler

• There is a requirement that &std::strlen == &::strlen

• Why do we have this requirement - can wee change it ? (Note from myself: SD-8 forbids observing the address of standard names) - some functions like memchr already deal with this problem

• This proposal is more work than assumed by the paper. If we do it we should know it will require some implementer work

Guidance: Implement the paper in a standard library / compiler, taking into account that the implementation may not be able to change the C headers. Talks to implementers on the best way to proceed

[brycelelbach]

Re-adding the mailing-list review tag so that this will automatically be triaged when a new revision comes: mailing list review managers, here are some saved queries that filter out things that are needs-revision, etc.

[cor3ntin]

On Wed, Oct 21, 2020, 00:55 Bryce Adelstein Lelbach aka wash < notifications@github.com> wrote:

Re-adding the mailing-list review tag so that this will automatically be triaged when a new revision comes: mailing list review managers, here are some saved queries https://github.com/cplusplus/LEWG/wiki/Chairing-Paper-Queries that filter out things that are needs-revision, etc.

I don't think we need another round of mailing review on this one. If and when it has implementation i think it needs to go to the room with implementers present

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/cplusplus/papers/issues/730#issuecomment-713185904, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAKX7656JB6VUIENGJVBS7LSLYIP3ANCNFSM4KISD55Q .

[brycelelbach]

Where does it go next? LEWG meeting review? LWG?

-- Bryce Adelstein Lelbach aka wash (he/him/his) US Programming Language Standards (PL22) Chair ISO C++ Library Evolution Chair CppCon and C++Now Program Chair C++ Core Compute Libraries (Thrust, CUB, libcu++) Lead @ NVIDIA

On Tue, Oct 20, 2020, 23:00 cor3ntin notifications@github.com wrote:

On Wed, Oct 21, 2020, 00:55 Bryce Adelstein Lelbach aka wash < notifications@github.com> wrote:

Re-adding the mailing-list review tag so that this will automatically be triaged when a new revision comes: mailing list review managers, here are some saved queries https://github.com/cplusplus/LEWG/wiki/Chairing-Paper-Queries that filter out things that are needs-revision, etc.

I don't think we need another round of mailing review on this one. If and when it has implementation i think it needs to go to the room with implementers present

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/cplusplus/papers/issues/730#issuecomment-713185904, or unsubscribe < https://github.com/notifications/unsubscribe-auth/AAKX7656JB6VUIENGJVBS7LSLYIP3ANCNFSM4KISD55Q

.

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/cplusplus/papers/issues/730#issuecomment-713324436, or unsubscribe https://github.com/notifications/unsubscribe-auth/AADBG4QSD3SIONNOJ3SGBULSLZ2G3ANCNFSM4KISD55Q .

[cor3ntin]

On Wed, 21 Oct 2020 at 08:06, Bryce Adelstein Lelbach aka wash < notifications@github.com> wrote:

Where does it go next? LEWG meeting review? LWG?

LEWG meeting sorry (with implementers present)

-- Bryce Adelstein Lelbach aka wash (he/him/his) US Programming Language Standards (PL22) Chair ISO C++ Library Evolution Chair CppCon and C++Now Program Chair C++ Core Compute Libraries (Thrust, CUB, libcu++) Lead @ NVIDIA

On Tue, Oct 20, 2020, 23:00 cor3ntin notifications@github.com wrote:

On Wed, Oct 21, 2020, 00:55 Bryce Adelstein Lelbach aka wash < notifications@github.com> wrote:

Re-adding the mailing-list review tag so that this will automatically be triaged when a new revision comes: mailing list review managers, here are some saved queries https://github.com/cplusplus/LEWG/wiki/Chairing-Paper-Queries that filter out things that are needs-revision, etc.

I don't think we need another round of mailing review on this one. If and when it has implementation i think it needs to go to the room with implementers present

— You are receiving this because you commented. Reply to this email directly, view it on GitHub <https://github.com/cplusplus/papers/issues/730#issuecomment-713185904 , or unsubscribe <

https://github.com/notifications/unsubscribe-auth/AAKX7656JB6VUIENGJVBS7LSLYIP3ANCNFSM4KISD55Q

.

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/cplusplus/papers/issues/730#issuecomment-713324436, or unsubscribe < https://github.com/notifications/unsubscribe-auth/AADBG4QSD3SIONNOJ3SGBULSLZ2G3ANCNFSM4KISD55Q

.

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/cplusplus/papers/issues/730#issuecomment-713327573, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAKX763V52XTTFN5SU4T6KDSLZ277ANCNFSM4KISD55Q .

[brycelelbach]

Thy will be done.

[brycelelbach]

Closing due to more than 1 year of inactivity. Please re-open if further work is expected.