[constexpr.functions] (original) (raw)
16 Library introduction [library]
16.4 Library-wide requirements [requirements]
16.4.6 Conforming implementations [conforming]
16.4.6.7 Constexpr functions and constructors [constexpr.functions]
This document explicitly requires that certain standard library functions areconstexpr ([dcl.constexpr]).
An implementation shall not declare any standard library function signature as constexpr except for those where it is explicitly required.
Within any header that provides any non-defining declarations of constexpr functions or constructors an implementation shall provide corresponding definitions.