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cppdraft/pairs/spec.md

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+[pairs.spec]
+
+# 22 General utilities library [[utilities]](./#utilities)
+
+## 22.3 Pairs [[pairs]](pairs#spec)
+
+### 22.3.3 Specialized algorithms [pairs.spec]
+
+[🔗](#lib:operator==,pair)
+
+`template<class T1, class T2, class U1, class U2>
+  constexpr bool operator==(const pair<T1, T2>& x, const pair<U1, U2>& y);
+`
+
+[1](#1)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/utilities.tex#L1305)
+
+*Constraints*: x.first == y.first and x.second == y.second are
+valid expressions and
+each of decltype(x.first == y.first) anddecltype(x.second == y.second) models *boolean-  
+testable*[.](#1.sentence-1)
+
+[2](#2)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/utilities.tex#L1312)
+
+*Returns*: x.first == y.first && x.second == y.second[.](#2.sentence-1)
+
+[🔗](#lib:operator%3c=%3e,pair)
+
+`template<class T1, class T2, class U1, class U2>
+  constexpr common_comparison_category_t<synth-three-way-result<T1, U1>,
+                                         synth-three-way-result<T2, U2>>
+    operator<=>(const pair<T1, T2>& x, const pair<U1, U2>& y);
+`
+
+[3](#3)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/utilities.tex#L1326)
+
+*Effects*: Equivalent to:if (auto c = *synth-three-way*(x.first, y.first); c != 0) return c;return *synth-three-way*(x.second, y.second);
+
+[🔗](#lib:swap,pair)
+
+`template<class T1, class T2>
+  constexpr void swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
+template<class T1, class T2>
+  constexpr void swap(const pair<T1, T2>& x, const pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
+`
+
+[4](#4)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/utilities.tex#L1344)
+
+*Constraints*: 
+
+- [(4.1)](#4.1)
+
+  For the first overload,is_swappable_v<T1> is true andis_swappable_v<T2> is true[.](#4.1.sentence-1)
+
+- [(4.2)](#4.2)
+
+  For the second overload,is_swappable_v<const T1> is true andis_swappable_v<const T2> is true[.](#4.2.sentence-1)
+
+[5](#5)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/utilities.tex#L1357)
+
+*Effects*: Equivalent to x.swap(y)[.](#5.sentence-1)
+
+[🔗](#lib:make_pair)
+
+`template<class T1, class T2>
+  constexpr pair<unwrap_ref_decay_t<T1>, unwrap_ref_decay_t<T2>> make_pair(T1&& x, T2&& y);
+`
+
+[6](#6)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/utilities.tex#L1369)
+
+*Returns*: pair<unwrap_ref_decay_t<T1>,
+ unwrap_ref_decay_t<T2>>(std::forward<T1>(x), std::forward<T2>(y))
+
+[7](#7)
+
+[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/utilities.tex#L1377)
+
+[*Example [1](#example-1)*:
+
+In place of:return pair<int, double>(5, 3.1415926); // explicit types a C++ program may contain:return make_pair(5, 3.1415926); // types are deduced
+
+— *end example*]