On 23/08/2021 00:36, Ivan Matek via Boost wrote:
On Sun, Aug 22, 2021 at 10:29 PM Robert Ramey via Boost < boost@lists.boost.org> wrote:
Yes.... but the function should really return the same value in both constexpr and runtime usage.
LOL - for me, the whole point of this is to use a different value depending on whether or not the value is known at compile time. Maybe someone wants to opine on this.
I think it would help discussion if you or John could provide a complete use case when different result is desired for a function depending on if it is running at compile time or not?
I could be wrong, but I don't believe that that would be a valid use case, like you, the intended usage is to optimize runtime and compile time usage, ie: constexpr int f(int i) { if(std::is_constant_evaluated()) { // constexpr friendly code here } else { // Maybe use a function that's super fast but not constexpr safe } } John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus