// C++N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf
#define msg "C++N4606(231)18.3.2.7 numeric_limits specializations[numeric.special]p493.cpp"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.

#include <iostream>
#include <cstdlib>

namespace std {
template<> class numeric_limits<float> {
public:
static constexpr bool is_specialized = true;
inline static constexpr float min() noexcept { return 1.17549435E-38F; }
inline static constexpr float max() noexcept { return 3.40282347E+38F; }
inline static constexpr float lowest() noexcept { return -3.40282347E+38F; }
static constexpr int digits = 24;
static constexpr int digits10 = 6;
static constexpr int max_digits10 = 9;
static constexpr bool is_signed = true;
static constexpr bool is_integer = false;
static constexpr bool is_exact = false;
static constexpr int radix = 2;
inline static constexpr float epsilon() noexcept { return 1.19209290E-07F; }
inline static constexpr float round_error() noexcept { return 0.5F; }
static constexpr int min_exponent = -125;
static constexpr int min_exponent10 = - 37;
static constexpr int max_exponent = +128;
static constexpr int max_exponent10 = + 38;
static constexpr bool has_infinity = true;
static constexpr bool has_quiet_NaN = true;
static constexpr bool has_signaling_NaN = true;
static constexpr float_denorm_style has_denorm = denorm_absent;
static constexpr bool has_denorm_loss = false;
inline static constexpr float infinity() noexcept { return value ; }
inline static constexpr float quiet_NaN() noexcept { return value ; }
inline static constexpr float signaling_NaN() noexcept { return value ; }
inline static constexpr float denorm_min() noexcept { return min(); }
static constexpr bool is_iec559 = true;
static constexpr bool is_bounded = true;
static constexpr bool is_modulo = false;
static constexpr bool traps = true;
static constexpr bool tinyness_before = true;
static constexpr float_round_style round_style = round_to_nearest;
};

int main() {
  std::cout<< msg << std::endl;
  return EXIT_SUCCESS;
}

$ ./cppwa17.sh p493
$ clang++ p493.cpp -std=c++17 -Wall
p493.cpp:35:60: error: use of undeclared identifier 'value'; did you mean 'money_base::value'?
inline static constexpr float infinity() noexcept { return value ; }
                                                           ^~~~~
                                                           money_base::value
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/locale:2595:43: note: 'money_base::value' declared here
    enum part {none, space, symbol, sign, value};
                                          ^
p493.cpp:36:61: error: use of undeclared identifier 'value'; did you mean 'money_base::value'?
inline static constexpr float quiet_NaN() noexcept { return value ; }
                                                            ^~~~~
                                                            money_base::value
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/locale:2595:43: note: 'money_base::value' declared here
    enum part {none, space, symbol, sign, value};
                                          ^
p493.cpp:37:65: error: use of undeclared identifier 'value'; did you mean 'money_base::value'?
inline static constexpr float signaling_NaN() noexcept { return value ; }
                                                                ^~~~~
                                                                money_base::value
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/locale:2595:43: note: 'money_base::value' declared here
    enum part {none, space, symbol, sign, value};
                                          ^
p493.cpp:50:30: error: use of undeclared identifier 'epsilon'
  static constexpr float e = epsilon();
                             ^
p493.cpp:51:34: error: static_assert expression is not an integral constant expression
  static_assert(1.19209290E-07F==e, "1.19209290E-07F==e");
                ~~~~~~~~~~~~~~~~~^
p493.cpp:52:13: error: use of undeclared identifier 'epsilon'
  float f = epsilon();
            ^
6 errors generated.

$ g++-7 p493.cpp -std=c++17  -Wall
p493.cpp:11:18: error: redefinition of 'class std::numeric_limits<float>'
 template<> class numeric_limits<float> {
                  ^~~~~~~~~~~~~~~~~~~~~
In file included from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/string_view:40:0,
                 from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/bits/basic_string.h:48,
                 from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/string:52,
                 from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/bits/locale_classes.h:40,
                 from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/bits/ios_base.h:41,
                 from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/ios:42,
                 from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/ostream:38,
                 from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/iostream:39,
                 from p493.cpp:6:
/usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/limits:1594:12: note: previous definition of 'class std::numeric_limits<float>'
     struct numeric_limits<float>
            ^~~~~~~~~~~~~~~~~~~~~
p493.cpp: In function 'int main()':
p493.cpp:50:30: error: 'epsilon' was not declared in this scope
   static constexpr float e = epsilon();
                              ^~~~~~~
p493.cpp:51:3: error: non-constant condition for static assertion
   static_assert(1.19209290E-07F==e, "1.19209290E-07F==e");
   ^~~~~~~~~~~~~