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<header data-kunai-mdinfo="{"meta": {"header": ["functional"], "namespace": ["std"], "class": ["move_only_function"], "id-type": ["function"], "cpp": ["cpp23"]}, "sources": [{"id": "020c6d3a9f3fdfa356323632915cbf9ceb8814ec", "source": "#include <cassert>\n#include <functional>\n#include <iostream>\n#include <numeric>\n#include <utility>\n\nstruct ident_functor {\n int operator()(int x) const\n { return x; }\n};\n\nint ident_func(int x)\n{ return x; }\n\nstruct X {\n int value;\n\n int add_member_func(int x) const\n { return value + x; }\n};\n\nstruct add_functor {\n int value;\n\n add_functor(int v) : value(v) {}\n add_functor(std::initializer_list<int> lst, int iv)\n : value(std::accumulate(lst.begin(), lst.end(), iv)) {}\n\n int operator()(int x) const\n { return value + x; }\n};\n\n\nint main()\n{\n // (1) \u30c7\u30d5\u30a9\u30eb\u30c8\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\n // (2) \u30cc\u30eb\u30dd\u30a4\u30f3\u30bf\u3092\u53d7\u3051\u53d6\u308b\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\n // \u7a7a\u306emove_only_function\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f5c\u308b\n {\n std::move_only_function<int(int)> f1;\n assert(!f1);\n std::move_only_function<int(int)> f2 = nullptr;\n assert(!f2);\n }\n\n // (3) \u30e0\u30fc\u30d6\u69cb\u7bc9\n {\n std::move_only_function<int(int)> f = ident_functor();\n std::move_only_function<int(int)> g = std::move(f);\n assert(g && !f);\n\n int result = g(1);\n std::cout << \"(3) : \" << result << std::endl;\n }\n\n // (4) \u95a2\u6570\u30dd\u30a4\u30f3\u30bf\u3092\u53d7\u3051\u53d6\u3063\u3066\u69cb\u7bc9\n {\n std::move_only_function<int(int)> f = ident_func;\n\n int result = f(1);\n std::cout << \"(4) function pointer : \" << result << std::endl;\n }\n // (4) \u95a2\u6570\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u53d7\u3051\u53d6\u3063\u3066\u69cb\u7bc9\n {\n std::move_only_function<int(int)> f = ident_functor();\n\n int result = f(1);\n std::cout << \"(4) function object : \" << result << std::endl;\n }\n // (4) \u30e1\u30f3\u30d0\u95a2\u6570\u30dd\u30a4\u30f3\u30bf\u3092\u53d7\u3051\u53d6\u3063\u305f\u69cb\u7bc9\n {\n std::move_only_function<int(const X&, int)> f = &X::add_member_func;\n\n X x{2};\n int result = f(x, 1);\n std::cout << \"(4) member function pointer : \" << result << std::endl;\n }\n // (4) \u30e1\u30f3\u30d0\u5909\u6570\u30dd\u30a4\u30f3\u30bf\u3092\u53d7\u3051\u53d6\u3063\u305f\u69cb\u7bc9\n {\n std::move_only_function<int(const X&)> f = &X::value;\n X x{2};\n int result = f(x);\n std::cout << \"(4) member variable pointer : \" << result << std::endl;\n }\n\n // (5) \u5f15\u6570\u30ea\u30b9\u30c8\u306b\u3088\u308b\u76f4\u63a5\u69cb\u7bc9\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\n {\n std::move_only_function<int(int)> f(std::in_place_type<add_functor>, 2);\n int result = f(1);\n std::cout << \"(5) : \" << result << std::endl;\n }\n\n // (6) initializer_list\uff0b\u5f15\u6570\u30ea\u30b9\u30c8\u306b\u3088\u308b\u76f4\u63a5\u69cb\u7bc9\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\n {\n std::move_only_function<int(int)> f(std::in_place_type<add_functor>, std::initializer_list<int>{1, 2, 3}, 4);\n int result = f(5);\n std::cout << \"(6) : \" << result << std::endl;\n }\n}\n"}], "page_id": ["reference", "functional", "move_only_function", "op_constructor"]}">
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最終更新日時(UTC):
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2025年08月23日 15時26分21秒
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<div class="identifier-type">function</div><div class="header"><functional></div><h1 itemprop="name"><span class="namespace" title="namespace std">std::</span><span class="class" title="class move_only_function">move_only_function::</span><span class="token">コンストラクタ</span><span class="cpp cpp23" title="C++23で追加">(C++23)</span></h1>
<div itemprop="articleBody"><p><div class="codehilite"><pre><span></span><code><span class="n">move_only_function</span><span class="p">()</span><span class="w"> </span><span class="k">noexcept</span><span class="p">;</span><span class="w"> </span><span class="c1">// (1)</span>
<span class="n">move_only_function</span><span class="p">(</span><span class="n"><a href="../../cstddef/nullptr_t.html">nullptr_t</a></span><span class="p">)</span><span class="w"> </span><span class="k">noexcept</span><span class="p">;</span><span class="w"> </span><span class="c1">// (2)</span>
<span class="n">move_only_function</span><span class="p">(</span><span class="n">move_only_function</span><span class="o">&&</span><span class="p">)</span><span class="w"> </span><span class="k">noexcept</span><span class="p">;</span><span class="w"> </span><span class="c1">// (3)</span>
<span class="k">template</span><span class="o"><</span><span class="k">class</span><span class="w"> </span><span class="nc">F</span><span class="o">></span><span class="w"> </span><span class="n">move_only_function</span><span class="p">(</span><span class="n">F</span><span class="o">&&</span><span class="p">);</span><span class="w"> </span><span class="c1">// (4)</span>
<span class="k">template</span><span class="o"><</span><span class="k">class</span><span class="w"> </span><span class="nc">T</span><span class="p">,</span><span class="w"> </span><span class="k">class</span><span class="p">...</span><span class="w"> </span><span class="n">Args</span><span class="o">></span>
<span class="k">explicit</span><span class="w"> </span><span class="n">move_only_function</span><span class="p">(</span><span class="n"><a href="../../utility/in_place_type_t.html">in_place_type_t</a></span><span class="o"><</span><span class="n">T</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="n">Args</span><span class="o">&&</span><span class="p">...);</span><span class="w"> </span><span class="c1">// (5)</span>
<span class="k">template</span><span class="o"><</span><span class="k">class</span><span class="w"> </span><span class="nc">T</span><span class="p">,</span><span class="w"> </span><span class="k">class</span><span class="w"> </span><span class="nc">U</span><span class="p">,</span><span class="w"> </span><span class="k">class</span><span class="p">...</span><span class="w"> </span><span class="n">Args</span><span class="o">></span>
<span class="k">explicit</span><span class="w"> </span><span class="n">move_only_function</span><span class="p">(</span><span class="n"><a href="../../utility/in_place_type_t.html">in_place_type_t</a></span><span class="o"><</span><span class="n">T</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="n">initializer_list</span><span class="o"><</span><span class="n">U</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="n">Args</span><span class="o">&&</span><span class="p">...);</span><span class="w"> </span><span class="c1">// (6)</span>
</code></pre></div>
</p>
<h2>概要</h2>
<p><code>move_only_function</code>オブジェクトを構築する。</p>
<p><code>move_only_function</code>クラステンプレートパラメータの<a class="cpprefjp-defined-word" data-desc="型をconstおよび・もしくはvolatileで修飾すること">CV修飾</a>子 <em>cv</em>, 参照修飾子 <em>ref</em>, noexcept<a class="cpprefjp-defined-word" data-desc="問題が発生したときに、現在実行位置を過去に通過・記録した位置に戻し、文脈情報を添えて紐づけられた処理(例外ハンドラー)を呼び出す仕組み。またはその事態">例外</a>指定 <em>noex</em> に応じて、説明用のプレースホルダ <em>inv-quals</em> を次のように定義する :</p>
<ul>
<li><em>ref</em> が空（参照修飾無し）ならば、<em>cv</em><code>&</code></li>
<li>そうでなければ、<em>cv</em> <em>ref</em></li>
</ul>
<p>また、説明用の<code>bool</code>型テンプレート定数<code>is-callable-from<VT></code>を下記のように定義する :</p>
<ul>
<li><em>noex</em> が<code>true</code>のとき : <code><a href="../../type_traits/is_nothrow_invocable_r.html">is_nothrow_invocable_r_v</a><R, VT /*cv*/ /*ref*/, ArgTypes...> && <a href="../../type_traits/is_nothrow_invocable_r.html">is_nothrow_invocable_r_v</a><R, VT /*inv-quals*/, ArgTypes...></code></li>
<li><em>noex</em> が<code>false</code>のとき : <code><a href="../../type_traits/is_invocable_r.html">is_invocable_r_v</a><R, VT /*cv*/ /*ref*/, ArgTypes...> && <a href="../../type_traits/is_invocable_r.html">is_invocable_r_v</a><R, VT /*inv-quals*/, ArgTypes...></code></li>
</ul>
<h2><a class="cpprefjp-defined-word" data-desc="関数等の意味論を構成する要素の1つ。Constraints。関数であればオーバーロード解決に参加するための条件、それ以外であれば受け付ける型の条件">テンプレートパラメータ制約</a></h2>
<ul>
<li>(4) : <code>VT</code>型を<code>decay_t<F></code>としたとき<ul>
<li><code>remove_cvref_t<F></code>が<code>move_only_function</code>と同一型ではなく、かつ</li>
<li><code>remove_cvref_t<F></code>が<code>in_place_type_t</code>の特殊化ではなく、かつ</li>
<li><code>is-callable-from<VT></code>が<code>true</code>であること</li>
</ul>
</li>
<li>(5) : <code>VT</code>型を<code>decay_t<T></code>としたとき<ul>
<li><code><a href="../../type_traits/is_constructible.html">is_constructible_v</a><VT, Args...></code>が<code>true</code>であり、かつ</li>
<li><code>is-callable-from<VT></code>が<code>true</code>であること</li>
</ul>
</li>
<li>(6) : <code>VT</code>型を<code>decay_t<T></code>としたとき<ul>
<li><code><a href="../../type_traits/is_constructible.html">is_constructible_v</a><VT, <a href="../../initializer_list/initializer_list.html">initializer_list</a><U>&, Args...></code>が<code>true</code>であり、かつ</li>
<li><code>is-callable-from<VT></code>が<code>true</code>であること</li>
</ul>
</li>
</ul>
<h2><a class="cpprefjp-defined-word" data-desc="関数等の意味論を構成する要素の1つ。Mandates。満たさなければプログラムが不適格となる要件。この要件は、オーバーロード解決によって選択された関数内での`static_assert`の定数条件式や、関数に対するdelete宣言などで表現できる">適格要件</a></h2>
<ul>
<li>(4) : <code>VT</code>型を<code>decay_t<F></code>としたとき、<code><a href="../../type_traits/is_constructible.html">is_constructible_v</a><VT, F></code>が<code>true</code>であること。</li>
<li>(5), (6) : <code>decay_t<T></code>が<code>T</code>と同一型であること。</li>
</ul>
<h2><a class="cpprefjp-defined-word" data-desc="関数等の意味論を構成する要素の1つ。Preconditions。関数呼び出し時に満たされていると関数が想定する条件。満たさなければ未定義の動作。契約属性の`[[expects]]`に相当">事前条件</a></h2>
<ul>
<li>(4) : <code>VT</code>型を<code>decay_t<F></code>としたとき<ul>
<li><code>VT</code>がCpp17Destructible要件を満たすこと。</li>
<li><code><a href="../../type_traits/is_move_constructible.html">is_move_constructible_v</a><VT></code>が<code>true</code>の場合、<code>VT</code>がCpp17MoveConstructible要件を満たすこと。</li>
</ul>
</li>
<li>(5), (6) : <code>VT</code>型を<code>decay_t<T></code>としたとき<ul>
<li><code>VT</code>がCpp17Destructible要件を満たすこと。</li>
<li><code><a href="../../type_traits/is_move_constructible.html">is_move_constructible_v</a><VT></code>が<code>true</code>の場合、<code>VT</code>がCpp17MoveConstructible要件を満たすこと。</li>
</ul>
</li>
</ul>
<h2>効果</h2>
<ul>
<li>(1), (2) : 関数を持たない空の<code>move_only_function</code>オブジェクトを構築する。この方法で構築した後、<code><a href="op_bool.html">operator bool</a></code>は<code>false</code>を返す。</li>
<li>(3) : <code>f</code>が保持する状態を<code>*this</code>に移動する。移動された後の<code>f</code>は、<a class="cpprefjp-defined-word" data-desc="未規定の動作。事前の断りなく処理系によって異なる動作をする" href="../../../implementation-compliance.html#dfn-unspecified-behavior">未規定</a>な値を持つ有効な状態となる。</li>
<li>(4) : <code>*this</code>の格納オブジェクトを<ul>
<li><code>f</code>が関数ポインタ型、メンバ関数ポインタ型、メンバ変数ポインタ型いずれかのヌルポインタ値の場合、値を保持しない。</li>
<li><code>remove_cvref_t<F></code>が<code>move_only_function</code>の特殊化であり、かつ値を保持していない場合、値を保持しない。</li>
<li>そうでなければ、<code>*this</code>が保持する<code>VT</code>型の格納オブジェクトを、<code>std::forward<F>(f)</code>で<a class="cpprefjp-defined-word" data-desc="direct-non-list-initialization。リスト初期化ではない直接初期化">直接非リスト初期化</a>する。</li>
</ul>
</li>
<li>(5) : <code>*this</code>が保持する<code>VT</code>型の格納オブジェクトを、<code>std::forward<Args>(args)...</code>で<a class="cpprefjp-defined-word" data-desc="direct-non-list-initialization。リスト初期化ではない直接初期化">直接非リスト初期化</a>する。</li>
<li>(6) : <code>*this</code>が保持する<code>VT</code>型の格納オブジェクトを、<code>ilist, std::forward<Args>(args)...</code>で<a class="cpprefjp-defined-word" data-desc="direct-non-list-initialization。リスト初期化ではない直接初期化">直接非リスト初期化</a>する。</li>
</ul>
<h2><a class="cpprefjp-defined-word" data-desc="問題が発生したときに、現在実行位置を過去に通過・記録した位置に戻し、文脈情報を添えて紐づけられた処理(例外ハンドラー)を呼び出す仕組み。またはその事態">例外</a></h2>
<ul>
<li>(1), (2), (3) : 投げない</li>
<li>(4), (5), (6) : 格納オブジェクトの初期化から<a class="cpprefjp-defined-word" data-desc="問題が発生したときに、現在実行位置を過去に通過・記録した位置に戻し、文脈情報を添えて紐づけられた処理(例外ハンドラー)を呼び出す仕組み。またはその事態">例外</a>が投げられる可能性がある。<code>VT</code>が関数ポインタまたは<code><a href="../reference_wrapper.html">reference_wrapper</a></code>の特殊化いずれでもなければ、<code>bad_alloc</code><a class="cpprefjp-defined-word" data-desc="問題が発生したときに、現在実行位置を過去に通過・記録した位置に戻し、文脈情報を添えて紐づけられた処理(例外ハンドラー)を呼び出す仕組み。またはその事態">例外</a>が投げられる可能性がある。</li>
</ul>
<h2>例</h2>
<p><div class="yata" id="020c6d3a9f3fdfa356323632915cbf9ceb8814ec"><div class="codehilite"><pre><span></span><code><span class="cp">#include <a href="../../cassert.html"><cassert></a></span>
<span class="cp">#include <a href="../../functional.html"><functional></a></span>
<span class="cp">#include <a href="../../iostream.html"><iostream></a></span>
<span class="cp">#include <a href="../../numeric.html"><numeric></a></span>
<span class="cp">#include <a href="../../utility.html"><utility></a></span>
<span class="k">struct</span><span class="w"> </span><span class="nc">ident_functor</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="nf">operator</span><span class="p">()(</span><span class="kt">int</span><span class="w"> </span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="k">const</span>
<span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">x</span><span class="p">;</span><span class="w"> </span><span class="p">}</span>
<span class="p">};</span>
<span class="kt">int</span><span class="w"> </span><span class="nf">ident_func</span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">x</span><span class="p">)</span>
<span class="p">{</span><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">x</span><span class="p">;</span><span class="w"> </span><span class="p">}</span>
<span class="k">struct</span><span class="w"> </span><span class="nc">X</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">value</span><span class="p">;</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="nf">add_member_func</span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="k">const</span>
<span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">value</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">x</span><span class="p">;</span><span class="w"> </span><span class="p">}</span>
<span class="p">};</span>
<span class="k">struct</span><span class="w"> </span><span class="nc">add_functor</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">value</span><span class="p">;</span>
<span class="w"> </span><span class="n">add_functor</span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">v</span><span class="p">)</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">value</span><span class="p">(</span><span class="n">v</span><span class="p">)</span><span class="w"> </span><span class="p">{}</span>
<span class="w"> </span><span class="n">add_functor</span><span class="p">(</span><span class="n"><a href="../../initializer_list/initializer_list.html">std::initializer_list</a></span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="w"> </span><span class="n">lst</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">iv</span><span class="p">)</span>
<span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="n">value</span><span class="p">(</span><span class="n"><a href="../../numeric/accumulate.html">std::accumulate</a></span><span class="p">(</span><span class="n">lst</span><span class="p">.</span><span class="n">begin</span><span class="p">(),</span><span class="w"> </span><span class="n">lst</span><span class="p">.</span><span class="n">end</span><span class="p">(),</span><span class="w"> </span><span class="n">iv</span><span class="p">))</span><span class="w"> </span><span class="p">{}</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="k">operator</span><span class="p">()(</span><span class="kt">int</span><span class="w"> </span><span class="n">x</span><span class="p">)</span><span class="w"> </span><span class="k">const</span>
<span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">value</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">x</span><span class="p">;</span><span class="w"> </span><span class="p">}</span>
<span class="p">};</span>
<span class="kt">int</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span>
<span class="p">{</span>
<span class="w"> </span><span class="c1">// (1) デフォルトコンストラクタ</span>
<span class="w"> </span><span class="c1">// (2) ヌルポインタを受け取るコンストラクタ</span>
<span class="w"> </span><span class="c1">// 空のmove_only_functionオブジェクトを作る</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f1</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../../cassert/assert.html">assert</a></span><span class="p">(</span><span class="o">!</span><span class="n">f1</span><span class="p">);</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">nullptr</span><span class="p">;</span>
<span class="w"> </span><span class="n"><a href="../../cassert/assert.html">assert</a></span><span class="p">(</span><span class="o">!</span><span class="n">f2</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">// (3) ムーブ構築</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ident_functor</span><span class="p">();</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">g</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="../../utility/move.html">std::move</a></span><span class="p">(</span><span class="n">f</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../cassert/assert.html">assert</a></span><span class="p">(</span><span class="n">g</span><span class="w"> </span><span class="o">&&</span><span class="w"> </span><span class="o">!</span><span class="n">f</span><span class="p">);</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">g</span><span class="p">(</span><span class="mi">1</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"(3) : "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">// (4) 関数ポインタを受け取って構築</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ident_func</span><span class="p">;</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="mi">1</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"(4) function pointer : "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">// (4) 関数オブジェクトを受け取って構築</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">ident_functor</span><span class="p">();</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="mi">1</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"(4) function object : "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">// (4) メンバ関数ポインタを受け取った構築</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="k">const</span><span class="w"> </span><span class="n">X</span><span class="o">&</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&</span><span class="n">X</span><span class="o">::</span><span class="n">add_member_func</span><span class="p">;</span>
<span class="w"> </span><span class="n">X</span><span class="w"> </span><span class="n">x</span><span class="p">{</span><span class="mi">2</span><span class="p">};</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="mi">1</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"(4) member function pointer : "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">// (4) メンバ変数ポインタを受け取った構築</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="k">const</span><span class="w"> </span><span class="n">X</span><span class="o">&</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&</span><span class="n">X</span><span class="o">::</span><span class="n">value</span><span class="p">;</span>
<span class="w"> </span><span class="n">X</span><span class="w"> </span><span class="n">x</span><span class="p">{</span><span class="mi">2</span><span class="p">};</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="n">x</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"(4) member variable pointer : "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">// (5) 引数リストによる直接構築コンストラクタ</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">in_place_type</span><span class="o"><</span><span class="n">add_functor</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">);</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="mi">1</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"(5) : "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">// (6) initializer_list＋引数リストによる直接構築コンストラクタ</span>
<span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">std</span><span class="o">::</span><span class="n">move_only_function</span><span class="o"><</span><span class="kt">int</span><span class="p">(</span><span class="kt">int</span><span class="p">)</span><span class="o">></span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="n">std</span><span class="o">::</span><span class="n">in_place_type</span><span class="o"><</span><span class="n">add_functor</span><span class="o">></span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../../initializer_list/initializer_list.html">std::initializer_list</a></span><span class="o"><</span><span class="kt">int</span><span class="o">></span><span class="p">{</span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="p">},</span><span class="w"> </span><span class="mi">4</span><span class="p">);</span>
<span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">f</span><span class="p">(</span><span class="mi">5</span><span class="p">);</span>
<span class="w"> </span><span class="n"><a href="../../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="s">"(6) : "</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">result</span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n"><a href="../../ostream/endl.html">std::endl</a></span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="p">}</span>
</code></pre></div>
</div></p>
<h3>出力</h3>
<p><pre><code>(3) : 1
(4) function pointer : 1
(4) function object : 1
(4) member function pointer : 3
(4) member variable pointer : 2
(5) : 3
(6) : 15
</code></pre></p>
<h2>バージョン</h2>
<h3>言語</h3>
<ul>
<li>C++23</li>
</ul>
<h3>処理系</h3>
<ul>
<li><a href="../../../implementation.html#clang">Clang</a>: ??</li>
<li><a href="../../../implementation.html#gcc">GCC</a>: 12.1 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
<li><a href="../../../implementation.html#icc">ICC</a>: ??</li>
<li><a href="../../../implementation.html#visual_cpp">Visual C++</a>: ??</li>
</ul>
<h2>参照</h2>
<ul>
<li><a href="https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p0288r9.html" target="_blank">P0288R9 move_only_function</a></li>
</ul></div>
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