28 Numerics library [numerics]

The library-defined partial specializations of mathematical constant variable templates are initialized with the nearest representable values of e, $\log {}_{2}e$, $\log {}_{10}e$, π, $\frac{1}{\pi }$, $\frac{1}{\sqrt{\pi }}$, ln2, ln10, $\sqrt{2}$, $\sqrt{3}$, $\frac{1}{\sqrt{3}}$, the Euler-Mascheroni γ constant, and the golden ratio φ constant $\frac{1+\sqrt{5}}{2}$, respectively.

Pursuant to [namespace.std], a program may partially or explicitly specialize a mathematical constant variable template provided that the specialization depends on a program-defined type.

A program that instantiates a primary template of a mathematical constant variable template is ill-formed.