Re: [Boost-users] generalize boost macros

That's exactly my problem.

namespace std { // declare missing log2, cannot say constexpr: compilererror inline float128_t log2(const float128_t& arg) noexcept { return log2q(arg); } }

There's no conceivable way we can implement that as a constexpr algorithm.

// also not constexpr inline float128_t myfunc(const float128_t& arg) noexcept { // log2_e not available // constexpr float128_t factor = boost::math::constants::log2_e();

// compiler generates a function call to log2 const float128_t factor = std::log2(boost::math::constants::e());

return arg*factor; }

log2(e) == 1/log(2) So: constexpr float128_t log2_e = 1 / boost::math::constants::ln_two(); does actually work just fine. Note that we cannot provide every single conceivable constant, so you can also define your own: namespace boost {    namespace math {       namespace constants {          BOOST_DEFINE_MATH_CONSTANT(log2_e, 1.4426950408889634073599246810018921374266459541529859341, "1.4426950408889634073599246810018921374266459541529859341354494069311092191811850798855266228935063444969975183096");       }    } } Which is also constepxr for float128_t. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus