86 lines
4.3 KiB
Markdown
86 lines
4.3 KiB
Markdown
[cmp.weakord]
|
||
|
||
# 17 Language support library [[support]](./#support)
|
||
|
||
## 17.12 Comparisons [[cmp]](cmp#weakord)
|
||
|
||
### 17.12.2 Comparison category types [[cmp.categories]](cmp.categories#cmp.weakord)
|
||
|
||
#### 17.12.2.3 Class weak_ordering [cmp.weakord]
|
||
|
||
[1](#1)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L5019)
|
||
|
||
The weak_ordering type is typically used
|
||
as the result type of a three-way comparison operator ([[expr.spaceship]](expr.spaceship "7.6.8 Three-way comparison operator"))
|
||
for a type that admits
|
||
all of the six two-way comparison operators ([[expr.rel]](expr.rel "7.6.9 Relational operators"), [[expr.eq]](expr.eq "7.6.10 Equality operators"))
|
||
and for which equality need not imply substitutability[.](#1.sentence-1)
|
||
|
||
[ð](#lib:weak_ordering)
|
||
|
||
namespace std {class weak_ordering {int *value*; // *exposition only*// exposition-only constructorsconstexpr explicit weak_ordering(*ord* v) noexcept : *value*(int(v)) {} // *exposition only*public:// valid valuesstatic const weak_ordering less; static const weak_ordering equivalent; static const weak_ordering greater; // conversionsconstexpr operator partial_ordering() const noexcept; // comparisonsfriend constexpr bool operator==(weak_ordering v, *unspecified*) noexcept; friend constexpr bool operator==(weak_ordering v, weak_ordering w) noexcept = default; friend constexpr bool operator< (weak_ordering v, *unspecified*) noexcept; friend constexpr bool operator> (weak_ordering v, *unspecified*) noexcept; friend constexpr bool operator<=(weak_ordering v, *unspecified*) noexcept; friend constexpr bool operator>=(weak_ordering v, *unspecified*) noexcept; friend constexpr bool operator< (*unspecified*, weak_ordering v) noexcept; friend constexpr bool operator> (*unspecified*, weak_ordering v) noexcept; friend constexpr bool operator<=(*unspecified*, weak_ordering v) noexcept; friend constexpr bool operator>=(*unspecified*, weak_ordering v) noexcept; friend constexpr weak_ordering operator<=>(weak_ordering v, *unspecified*) noexcept; friend constexpr weak_ordering operator<=>(*unspecified*, weak_ordering v) noexcept; }; // valid values' definitionsinline constexpr weak_ordering weak_ordering::less(*ord*::*less*); inline constexpr weak_ordering weak_ordering::equivalent(*ord*::*equivalent*); inline constexpr weak_ordering weak_ordering::greater(*ord*::*greater*);}
|
||
|
||
[ð](#lib:operator_partial_ordering,weak_ordering)
|
||
|
||
`constexpr operator partial_ordering() const noexcept;
|
||
`
|
||
|
||
[2](#2)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L5075)
|
||
|
||
*Returns*: *value* == 0 ? partial_ordering::equivalent :*value* < 0 ? partial_ordering::less : partial_ordering::greater
|
||
|
||
[ð](#lib:operator==,weak_ordering)
|
||
|
||
`constexpr bool operator==(weak_ordering v, unspecified) noexcept;
|
||
constexpr bool operator< (weak_ordering v, unspecified) noexcept;
|
||
constexpr bool operator> (weak_ordering v, unspecified) noexcept;
|
||
constexpr bool operator<=(weak_ordering v, unspecified) noexcept;
|
||
constexpr bool operator>=(weak_ordering v, unspecified) noexcept;
|
||
`
|
||
|
||
[3](#3)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L5098)
|
||
|
||
*Returns*: v.*value* @ 0 for operator@[.](#3.sentence-1)
|
||
|
||
[ð](#lib:operator%3c,weak_ordering_)
|
||
|
||
`constexpr bool operator< (unspecified, weak_ordering v) noexcept;
|
||
constexpr bool operator> (unspecified, weak_ordering v) noexcept;
|
||
constexpr bool operator<=(unspecified, weak_ordering v) noexcept;
|
||
constexpr bool operator>=(unspecified, weak_ordering v) noexcept;
|
||
`
|
||
|
||
[4](#4)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L5115)
|
||
|
||
*Returns*: 0 @ v.*value* for operator@[.](#4.sentence-1)
|
||
|
||
[ð](#lib:operator%3c=%3e,weak_ordering)
|
||
|
||
`constexpr weak_ordering operator<=>(weak_ordering v, unspecified) noexcept;
|
||
`
|
||
|
||
[5](#5)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L5126)
|
||
|
||
*Returns*: v[.](#5.sentence-1)
|
||
|
||
[ð](#lib:operator%3c=%3e,weak_ordering_)
|
||
|
||
`constexpr weak_ordering operator<=>(unspecified, weak_ordering v) noexcept;
|
||
`
|
||
|
||
[6](#6)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L5137)
|
||
|
||
*Returns*: v < 0 ? weak_ordering::greater : v > 0 ? weak_ordering::less : v[.](#6.sentence-1)
|