boost/math/ccmath/isnan.hpp
// (C) Copyright Matt Borland 2021.
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_MATH_CCMATH_ISNAN
#define BOOST_MATH_CCMATH_ISNAN
#include <boost/math/special_functions/fpclassify.hpp>
#include <boost/math/ccmath/detail/config.hpp>
#ifdef BOOST_MATH_NO_CCMATH
#error "The header <boost/math/isnan.hpp> can only be used in C++17 and later."
#endif
namespace boost::math::ccmath {
template <typename T>
inline constexpr bool isnan BOOST_MATH_PREVENT_MACRO_SUBSTITUTION(T x)
{
if(BOOST_MATH_IS_CONSTANT_EVALUATED(x))
{
return x != x;
}
else
{
using boost::math::isnan;
if constexpr (!std::is_integral_v<T>)
{
return (isnan)(x);
}
else
{
return (isnan)(static_cast<double>(x));
}
}
}
}
#endif // BOOST_MATH_CCMATH_ISNAN