Am 02.02.19 um 19:15 schrieb John Maddock via Boost-users:
This is not constexpr for float128_t and the compiler generates a function call. :-(
This works fine for me:
#include <boost/cstdfloat.hpp> #include <boost/math/constants/constants.hpp>
int main() { using boost::float128_t;
constexpr float128_t pi = boost::math::constants::pi<float128_t>();
return 0; }
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); } } // 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<float128_t>(); // compiler generates a function call to log2 const float128_t factor = std::log2(boost::math::constants::e<float128_t>()); return arg*factor; } thx Gero