Sticking with stuff that's in the standard, "constexpr" is, among other things, a more strongly-suggested "inline". Also, inlining is likely if you compile wit

Sticking with stuff that's in the standard, "constexpr" is, among other things, a more strongly-suggested "inline". Also, inlining is likely if you compile with -02/-03 and declare the function with internal visibility (in an anonymous namespace or with "static", although the latter is deprecated in favor of the former in C++).