[numeric.special]

# 17 Language support library [[support]](./#support)

## 17.3 Implementation properties [[support.limits]](support.limits#numeric.special)

### 17.3.5 Class template numeric_limits [[numeric.limits]](numeric.limits#numeric.special)

#### 17.3.5.3 numeric_limits specializations [numeric.special]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L1657)

All members shall be provided for all specializations[.](#1.sentence-1)

However, many values are only required to be meaningful under certain
conditions
(for example,epsilon() is only meaningful ifis_integer isfalse)[.](#1.sentence-2)

Any value that is not “meaningful” shall be set to 0 orfalse[.](#1.sentence-3)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L1670)

[*Example [1](#example-1)*: namespace std {template<> class numeric_limits<float> {public:static constexpr bool is_specialized = true; static constexpr float min() noexcept { return 1.17549435E-38F; }static constexpr float max() noexcept { return 3.40282347E+38F; }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; static constexpr float epsilon() noexcept { return 1.19209290E-07F; }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 infinity() noexcept { return *value*; }static constexpr float quiet_NaN() noexcept { return *value*; }static constexpr float signaling_NaN() noexcept { return *value*; }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; };} — *end example*]

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L1720)

The specialization forbool shall be provided as follows:

[🔗](#lib:numeric_limits%3cbool%3e)

namespace std {template<> class numeric_limits<bool> {public:static constexpr bool is_specialized = true; static constexpr bool min() noexcept { return false; }static constexpr bool max() noexcept { return true; }static constexpr bool lowest() noexcept { return false; }static constexpr int digits = 1; static constexpr int digits10 = 0; static constexpr int max_digits10 = 0; static constexpr bool is_signed = false; static constexpr bool is_integer = true; static constexpr bool is_exact = true; static constexpr int radix = 2; static constexpr bool epsilon() noexcept { return 0; }static constexpr bool round_error() noexcept { return 0; }static constexpr int min_exponent = 0; static constexpr int min_exponent10 = 0; static constexpr int max_exponent = 0; static constexpr int max_exponent10 = 0; static constexpr bool has_infinity = false; static constexpr bool has_quiet_NaN = false; static constexpr bool has_signaling_NaN = false; static constexpr bool infinity() noexcept { return 0; }static constexpr bool quiet_NaN() noexcept { return 0; }static constexpr bool signaling_NaN() noexcept { return 0; }static constexpr bool denorm_min() noexcept { return 0; }static constexpr bool is_iec559 = false; static constexpr bool is_bounded = true; static constexpr bool is_modulo = false; static constexpr bool traps = false; static constexpr bool tinyness_before = false; static constexpr float_round_style round_style = round_toward_zero; };}