>> In looking, it seems to me that making
>> std::chrono::system_clockusable in
>> constexpr contexts is pretty simple and invokes marking one function as
>> constexpr: now.
>
> Please don't.

+1

Also this strikes me as a good way to violate ODR.

Cheers,
Jeremy

On Mar 6 2025, at 4:00 pm, Thiago Macieira via Std-Proposals
<std-proposals_at_[hidden]> wrote:

> On Thursday, 6 March 2025 13:43:47 Pacific Standard Time Nikolaos D.
> Bougalis
> via Std-Proposals wrote:
>> In looking, it seems to me that making
>> std::chrono::system_clockusable in
>> constexpr contexts is pretty simple and invokes marking one function as
>> constexpr: now.
>
> Please don't. Your software should not depend on the time it was
> compiled at
> and should not change depending on that.
>
> std::chrono::system_clock::time_point now = {};
> if (!std::is_constant_evaluated()))
> now = std::chrono::system_clock::now();
>
>> Less exotic use cases include the ability to generate time-based
>> UUIDs at
>> compile time, to seed random number generators at compile time, potentially
>> warn when old code is compiled (not that there's anything wrong with that!)
>
> Please make your software reproducible: it should be bitwise exactly
> identical
> if it is compiled by the same compiler.
>
> --
> Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
> Principal Engineer - Intel DCAI Platform & System Engineering
>
>
>
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>