http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49813
--- Comment #8 from vincenzo Innocente <vincenzo.innocente at cern dot ch> 2011-07-22 11:06:41 UTC --- what about other "new C99 functions" such as cexprMath.cpp:16:64: error: 'float std::nextafter(float, float)' is not 'constexpr' cexprMath.cpp:17:58: error: 'float std::trunc(float)' is not 'constexpr' cexprMath.cpp:18:48: error: 'float std::lgamma(float)' is not 'constexpr' cexprMath.cpp:19:46: error: 'float std::erfc(float)' is not 'constexpr' ? have not tested all (yet). from #include <cmath> struct foo { static constexpr float a = std::cos(3.); static constexpr float c = std::exp(3.); static constexpr float d = std::log(3.); static constexpr float e1 = std::asin(1.); static constexpr float h = std::sqrt(.1); static constexpr float p = std::pow(1.3,-0.75); static constexpr float es = std::sinh(1.); static constexpr float ec = std::cosh(1.); static constexpr float et = std::tanh(1.); static constexpr float zs = std::asinh(1.2); static constexpr float zc = std::acosh(1.2); static constexpr float zt = std::atanh(.5); static constexpr float pi1 =std::nextafter(std::cos(-1.f),0.f); static constexpr float three =std::trunc(std::cos(-1.f)); static constexpr float l0 = std::lgamma(0.45f); static constexpr float er = std::erfc(0.45f); }; as we are on the subject: if the argument of the function is invalid such as static constexpr float nan1 = std::asin(1.45f); static constexpr float nan2 = std::sqrt(-1.45f); I get exactly the same error as above which is a bit confusing cexprMath.cpp:20:48: error: call to non-constexpr function 'float std::asin(float)' cexprMath.cpp:20:48: error: field initializer is not constant cexprMath.cpp:21:49: error: call to non-constexpr function 'float std::sqrt(float)' cexprMath.cpp:21:49: error: field initializer is not constant (the test of the message has changed between 4.6 and 4.7)