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_clock​ usable 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