On Mar 7, 2025, at 7:58 PM, Jeremy Rifkin via Std-Proposals <std-proposals_at_[hidden]> wrote:
>
> Would the proposal here be to make constexpr std::chrono give the invocation time or some fixed now time for the whole compilation?
>
> I'm just imagining:
>
> consteval void who_needs_fast_compilation_anyway() {
> auto start = std::chrono::system_clock::now();
> while(std::chrono::system_clock::now() < start + std::chrono::minutes(1)) {}
> }
>
> Cheers,
> Jeremy


Fwiw, I have this proposal crudely prototyped on __DATE__ and __TIME__. I ran your example through it and got:


test.cpp:135:5: error: call to consteval function 'who_needs_fast_compilation_anyway' is not a constant expression
  135 | who_needs_fast_compilation_anyway();
      | ^
test.cpp:52:9: note: constexpr evaluation hit maximum step limit; possible infinite loop?
   52 | {
      | ^

which seems like a reasonable result to me. Garbage in / garbage out sort of thing...

Howard