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<header data-kunai-mdinfo="{"meta": {"header": ["memory_resource"], "id-type": ["class"], "namespace": ["std::pmr"], "cpp": ["cpp17"]}, "sources": [{"id": "6ab416e52927deadf8e958c32cc0d23ffbdf1c2d", "source": "#include <iostream>\n#include <memory_resource>\n#include <cstddef>\n\n//\u30b9\u30bf\u30c3\u30af\u9818\u57df\u304b\u3089\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308bmemory_resource\u5b9f\u88c5\ntemplate<std::size_t N>\nstruct stack_resource : public std::pmr::memory_resource {\n\n stack_resource() = default;\n //\u30b3\u30d4\u30fc\u306b\u610f\u5473\u304c\u306a\u3044\u306e\u3067\u7981\u6b62\n stack_resource(const stack_resource&) = delete;\n stack_resource& operator=(const stack_resource&) = delete;\n\n void* do_allocate(std::size_t bytes, std::size_t alignment) override {\n //\u7a7a\u304d\u304c\u306a\u3044\n if (N <= m_index) throw std::bad_alloc{};\n\n //2\u306e\u7d2f\u4e57\u3092\u30c1\u30a7\u30c3\u30af\uff08AVX512\u306e\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u8981\u6c42\u3067\u3042\u308b64byte\u3092\u6700\u5927\u3068\u3057\u3066\u304a\u304f\uff09\n bool is_pow2 = false;\n for (std::size_t pow2 = 1; pow2 <= std::size_t(64); pow2 *= 2) {\n if (alignment == pow2) {\n is_pow2 = true;\n break;\n }\n }\n\n //2\u306e\u7d2f\u4e57\u3067\u306a\u3044\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u8981\u6c42\u306falignof(std::max_align_t)\u3078\n if (!is_pow2) {\n alignment = alignof(std::max_align_t);\n }\n\n auto addr = reinterpret_cast<std::uintptr_t>(&m_buffer[m_index]);\n\n //\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u8981\u6c42\u306b\u5408\u308f\u305b\u308b\n while ((addr & std::uintptr_t(alignment - 1)) != 0) {\n ++addr;\n ++m_index;\n }\n\n m_index += bytes;\n\n //\u30b5\u30a4\u30ba\u304c\u8db3\u308a\u306a\u304f\u306a\u3063\u305f\u3089\n if (N <= m_index) throw std::bad_alloc{};\n\n return reinterpret_cast<void*>(addr);\n }\n\n void do_deallocate(void* p, std::size_t bytes, [[maybe_unused]] std::size_t alignment) override {\n auto addr = static_cast<std::byte*>(p);\n auto end = std::end(m_buffer);\n\n if (m_buffer <= addr && addr < end) {\n //\u5f53\u3066\u305f\u9818\u57df\u3092\u30bc\u30ed\u57cb\u3081\u3059\u308b\u3060\u3051\n for (std::size_t i = 0; i < bytes; ++i) {\n if ((addr + i) < end) {\n addr[i] = std::byte(0);\n }\n }\n }\n\n }\n\n bool do_is_equal(const memory_resource& other) const noexcept override {\n return this == &other;\n }\n\nprivate:\n std::byte m_buffer[N]{};\n std::size_t m_index{};\n};\n\nint main(){\n stack_resource<100> s{};\n std::pmr::memory_resource* mr = &s;\n\n //int1\u3064\u5206\u306e\u9818\u57df\u3092int\u306e\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u8981\u6c42\uff08\u591a\u304f\u306e\u74b0\u5883\u3067\u5171\u306b4\u30d0\u30a4\u30c8\uff09\u3067\u30e1\u30e2\u30ea\u78ba\u4fdd\n void* p = mr->allocate(sizeof(int), alignof(int));\n //placement new \u3057\u3066\u69cb\u7bc9\n int* p_int = new(p) int{ 256 };\n\n std::cout << *p_int << std::endl;\n //\u4e00\u5fdc\u30a2\u30c9\u30ec\u30b9\u3092\u51fa\u529b\n std::cout << p << std::endl;\n std::cout << p_int << std::endl;\n\n //\u30c7\u30b9\u30c8\u30e9\u30af\u30bf\u3092\u547c\u3073\u51fa\u3057\u3066\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u7834\u68c4\n std::destroy_at(p_int);\n\n //\u30e1\u30e2\u30ea\u306e\u89e3\u653e\n mr->deallocate(p, sizeof(int), alignof(int));\n\n std::cout << std::boolalpha;\n\n stack_resource<10> s2{};\n //\u81ea\u5206\u4ee5\u5916\u3068\u306ftrue\u306b\u306a\u3089\u306a\u3044\n std::cout << (*mr == s) << std::endl;\n std::cout << (*mr == s2) << std::endl;\n}\n"}], "page_id": ["reference", "memory_resource", "memory_resource"]}">
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最終更新日時(UTC):
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2024年06月11日 13時45分38秒
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<div class="identifier-type">class</div><div class="header"><memory_resource></div><h1 itemprop="name"><span class="namespace" title="namespace std::pmr">std::pmr::</span><span class="token">memory_resource</span><span class="cpp cpp17" title="C++17で追加">(C++17)</span></h1>
<div itemprop="articleBody"><p><div class="codehilite"><pre><span></span><code><span class="k">namespace</span><span class="w"> </span><span class="nn">std</span><span class="o">::</span><span class="nn">pmr</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">class</span><span class="w"> </span><span class="nc">memory_resource</span><span class="p">;</span>
<span class="p">}</span>
</code></pre></div>
</p>
<h2>概要</h2>
<p><code>memory_resource</code>はメモリの確保・解放戦略と実際の処理を実装し、<code><a href="polymorphic_allocator.html">polymorphic_allocator</a></code>から利用されるためのインターフェースである。</p>
<h2>メンバ関数</h2>
<h3>構築・破棄</h3>
<table border="1" bordercolor="#888" style="border-collapse:collapse">
<thead>
<tr>
<th>名前</th>
<th>説明</th>
<th>対応バージョン</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>virtual ~memory_resource()</code></td>
<td>仮想デストラクタ</td>
<td>C++17</td>
</tr>
</tbody>
</table>
<h3>非仮想インターフェース（NVI）</h3>
<table border="1" bordercolor="#888" style="border-collapse:collapse">
<thead>
<tr>
<th>名前</th>
<th>説明</th>
<th>対応バージョン</th>
</tr>
</thead>
<tbody>
<tr>
<td><code><a href="memory_resource/allocate.html">allocate</a></code></td>
<td>メモリを確保する</td>
<td>C++17</td>
</tr>
<tr>
<td><code><a href="memory_resource/deallocate.html">deallocate</a></code></td>
<td>メモリを解放する</td>
<td>C++17</td>
</tr>
<tr>
<td><code><a href="memory_resource/is_equal.html">is_equal</a></code></td>
<td>オブジェクトを超えてメモリ領域の解放を行えるかを調べる</td>
<td>C++17</td>
</tr>
</tbody>
</table>
<h3>プライベート純粋仮想関数</h3>
<table border="1" bordercolor="#888" style="border-collapse:collapse">
<thead>
<tr>
<th>名前</th>
<th>説明</th>
<th>対応バージョン</th>
</tr>
</thead>
<tbody>
<tr>
<td><code><a href="memory_resource/do_allocate.html">do_allocate</a></code></td>
<td>メモリを確保する</td>
<td>C++17</td>
</tr>
<tr>
<td><code><a href="memory_resource/do_deallocate.html">do_deallocate</a></code></td>
<td>メモリを解放する</td>
<td>C++17</td>
</tr>
<tr>
<td><code><a href="memory_resource/do_is_equal.html">do_is_equal</a></code></td>
<td>オブジェクトを超えてメモリ領域の解放を行えるかを調べる</td>
<td>C++17</td>
</tr>
</tbody>
</table>
<h2>非メンバ関数</h2>
<table border="1" bordercolor="#888" style="border-collapse:collapse">
<thead>
<tr>
<th>名前</th>
<th>説明</th>
<th>対応バージョン</th>
</tr>
</thead>
<tbody>
<tr>
<td><code><a href="memory_resource/op_equal.html">operator==</a></code></td>
<td>等値比較</td>
<td>C++17</td>
</tr>
<tr>
<td><code><a href="memory_resource/op_not_equal.html">operator!=</a></code></td>
<td>非等値比較</td>
<td>C++17</td>
</tr>
</tbody>
</table>
<h2>実装する例</h2>
<p><div class="yata" id="6ab416e52927deadf8e958c32cc0d23ffbdf1c2d"><div class="codehilite"><pre><span></span><code><span class="cp">#include <a href="../iostream.html"><iostream></a></span>
<span class="cp">#include <a href="../memory_resource.html"><memory_resource></a></span>
<span class="cp">#include <a href="../cstddef.html"><cstddef></a></span>
<span class="c1">//スタック領域からメモリを割り当てるmemory_resource実装</span>
<span class="k">template</span><span class="o"><</span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">N</span><span class="o">></span>
<span class="k">struct</span><span class="w"> </span><span class="nc">stack_resource</span><span class="w"> </span><span class="o">:</span><span class="w"> </span><span class="k">public</span><span class="w"> </span><span class="n"><span style="color:#ff0000">std::pmr::memory_resource</span></span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">stack_resource</span><span class="p">()</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">default</span><span class="p">;</span>
<span class="w"> </span><span class="c1">//コピーに意味がないので禁止</span>
<span class="w"> </span><span class="n">stack_resource</span><span class="p">(</span><span class="k">const</span><span class="w"> </span><span class="n">stack_resource</span><span class="o">&</span><span class="p">)</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">delete</span><span class="p">;</span>
<span class="w"> </span><span class="n">stack_resource</span><span class="o">&</span><span class="w"> </span><span class="k">operator</span><span class="o">=</span><span class="p">(</span><span class="k">const</span><span class="w"> </span><span class="n">stack_resource</span><span class="o">&</span><span class="p">)</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">delete</span><span class="p">;</span>
<span class="w"> </span><span class="kt">void</span><span class="o">*</span><span class="w"> </span><span class="nf">do_allocate</span><span class="p">(</span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">bytes</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">alignment</span><span class="p">)</span><span class="w"> </span><span class="k">override</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">//空きがない</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">N</span><span class="w"> </span><span class="o"><=</span><span class="w"> </span><span class="n">m_index</span><span class="p">)</span><span class="w"> </span><span class="k">throw</span><span class="w"> </span><span class="n"><a href="../new/bad_alloc.html">std::bad_alloc</a></span><span class="p">{};</span>
<span class="w"> </span><span class="c1">//2の累乗をチェック（AVX512のアライメント要求である64byteを最大としておく）</span>
<span class="w"> </span><span class="kt">bool</span><span class="w"> </span><span class="n">is_pow2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">false</span><span class="p">;</span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">pow2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span><span class="w"> </span><span class="n">pow2</span><span class="w"> </span><span class="o"><=</span><span class="w"> </span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="p">(</span><span class="mi">64</span><span class="p">);</span><span class="w"> </span><span class="n">pow2</span><span class="w"> </span><span class="o">*=</span><span class="w"> </span><span class="mi">2</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">alignment</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="n">pow2</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">is_pow2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="nb">true</span><span class="p">;</span>
<span class="w"> </span><span class="k">break</span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="c1">//2の累乗でないアライメント要求はalignof(<a href="../cstddef/max_align_t.html">std::max_align_t</a>)へ</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="o">!</span><span class="n">is_pow2</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">alignment</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">alignof</span><span class="p">(</span><span class="n"><a href="../cstddef/max_align_t.html">std::max_align_t</a></span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">addr</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">reinterpret_cast</span><span class="o"><</span><span class="n"><a href="../cstdint/uintptr_t.html">std::uintptr_t</a></span><span class="o">></span><span class="p">(</span><span class="o">&</span><span class="n">m_buffer</span><span class="p">[</span><span class="n">m_index</span><span class="p">]);</span>
<span class="w"> </span><span class="c1">//アライメント要求に合わせる</span>
<span class="w"> </span><span class="k">while</span><span class="w"> </span><span class="p">((</span><span class="n">addr</span><span class="w"> </span><span class="o">&</span><span class="w"> </span><span class="n"><a href="../cstdint/uintptr_t.html">std::uintptr_t</a></span><span class="p">(</span><span class="n">alignment</span><span class="w"> </span><span class="o">-</span><span class="w"> </span><span class="mi">1</span><span class="p">))</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="mi">0</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="o">++</span><span class="n">addr</span><span class="p">;</span>
<span class="w"> </span><span class="o">++</span><span class="n">m_index</span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="n">m_index</span><span class="w"> </span><span class="o">+=</span><span class="w"> </span><span class="n">bytes</span><span class="p">;</span>
<span class="w"> </span><span class="c1">//サイズが足りなくなったら</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">N</span><span class="w"> </span><span class="o"><=</span><span class="w"> </span><span class="n">m_index</span><span class="p">)</span><span class="w"> </span><span class="k">throw</span><span class="w"> </span><span class="n"><a href="../new/bad_alloc.html">std::bad_alloc</a></span><span class="p">{};</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="k">reinterpret_cast</span><span class="o"><</span><span class="kt">void</span><span class="o">*></span><span class="p">(</span><span class="n">addr</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">do_deallocate</span><span class="p">(</span><span class="kt">void</span><span class="o">*</span><span class="w"> </span><span class="n">p</span><span class="p">,</span><span class="w"> </span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">bytes</span><span class="p">,</span><span class="w"> </span><span class="p">[[</span><span class="n">maybe_unused</span><span class="p">]]</span><span class="w"> </span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">alignment</span><span class="p">)</span><span class="w"> </span><span class="k">override</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">addr</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">static_cast</span><span class="o"><</span><span class="n"><a href="../cstddef/byte.html">std::byte</a></span><span class="o">*></span><span class="p">(</span><span class="n">p</span><span class="p">);</span>
<span class="w"> </span><span class="k">auto</span><span class="w"> </span><span class="n">end</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="../iterator/end.html">std::end</a></span><span class="p">(</span><span class="n">m_buffer</span><span class="p">);</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">m_buffer</span><span class="w"> </span><span class="o"><=</span><span class="w"> </span><span class="n">addr</span><span class="w"> </span><span class="o">&&</span><span class="w"> </span><span class="n">addr</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="n">end</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">//当てた領域をゼロ埋めするだけ</span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="n">bytes</span><span class="p">;</span><span class="w"> </span><span class="o">++</span><span class="n">i</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">((</span><span class="n">addr</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">i</span><span class="p">)</span><span class="w"> </span><span class="o"><</span><span class="w"> </span><span class="n">end</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">addr</span><span class="p">[</span><span class="n">i</span><span class="p">]</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n"><a href="../cstddef/byte.html">std::byte</a></span><span class="p">(</span><span class="mi">0</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="kt">bool</span><span class="w"> </span><span class="nf">do_is_equal</span><span class="p">(</span><span class="k">const</span><span class="w"> </span><span class="n">memory_resource</span><span class="o">&</span><span class="w"> </span><span class="n">other</span><span class="p">)</span><span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="k">noexcept</span><span class="w"> </span><span class="k">override</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="k">this</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="o">&</span><span class="n">other</span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="k">private</span><span class="o">:</span>
<span class="w"> </span><span class="n"><a href="../cstddef/byte.html">std::byte</a></span><span class="w"> </span><span class="n">m_buffer</span><span class="p">[</span><span class="n">N</span><span class="p">]{};</span>
<span class="w"> </span><span class="n"><a href="../cstddef/size_t.html">std::size_t</a></span><span class="w"> </span><span class="n">m_index</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="w"> </span><span class="n">stack_resource</span><span class="o"><</span><span class="mi">100</span><span class="o">></span><span class="w"> </span><span class="n">s</span><span class="p">{};</span>
<span class="w"> </span><span class="n"><span style="color:#ff0000">std::pmr::memory_resource</span></span><span class="o">*</span><span class="w"> </span><span class="n">mr</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="o">&</span><span class="n">s</span><span class="p">;</span>
<span class="w"> </span><span class="c1">//int1つ分の領域をintのアライメント要求（多くの環境で共に4バイト）でメモリ確保</span>
<span class="w"> </span><span class="kt">void</span><span class="o">*</span><span class="w"> </span><span class="n">p</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">mr</span><span class="o">-></span><span class="n"><a href="memory_resource/allocate.html">allocate</a></span><span class="p">(</span><span class="k">sizeof</span><span class="p">(</span><span class="kt">int</span><span class="p">),</span><span class="w"> </span><span class="k">alignof</span><span class="p">(</span><span class="kt">int</span><span class="p">));</span>
<span class="w"> </span><span class="c1">//placement new して構築</span>
<span class="w"> </span><span class="kt">int</span><span class="o">*</span><span class="w"> </span><span class="n">p_int</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="p">(</span><span class="n">p</span><span class="p">)</span><span class="w"> </span><span class="kt">int</span><span class="p">{</span><span class="w"> </span><span class="mi">256</span><span class="w"> </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="o">*</span><span class="n">p_int</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="c1">//一応アドレスを出力</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="n">p</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="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="n">p_int</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="c1">//デストラクタを呼び出してオブジェクトを破棄</span>
<span class="w"> </span><span class="n"><a href="../memory/destroy_at.html">std::destroy_at</a></span><span class="p">(</span><span class="n">p_int</span><span class="p">);</span>
<span class="w"> </span><span class="c1">//メモリの解放</span>
<span class="w"> </span><span class="n">mr</span><span class="o">-></span><span class="n"><a href="memory_resource/deallocate.html">deallocate</a></span><span class="p">(</span><span class="n">p</span><span class="p">,</span><span class="w"> </span><span class="k">sizeof</span><span class="p">(</span><span class="kt">int</span><span class="p">),</span><span class="w"> </span><span class="k">alignof</span><span class="p">(</span><span class="kt">int</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="n"><a href="../ios/boolalpha.html">std::boolalpha</a></span><span class="p">;</span>
<span class="w"> </span><span class="n">stack_resource</span><span class="o"><</span><span class="mi">10</span><span class="o">></span><span class="w"> </span><span class="n">s2</span><span class="p">{};</span>
<span class="w"> </span><span class="c1">//自分以外とはtrueにならない</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="p">(</span><span class="o">*</span><span class="n">mr</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="n">s</span><span class="p">)</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="n"><a href="../iostream/cout.html">std::cout</a></span><span class="w"> </span><span class="o"><<</span><span class="w"> </span><span class="p">(</span><span class="o">*</span><span class="n">mr</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="n">s2</span><span class="p">)</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="p">}</span>
</code></pre></div>
</div></p>
<h3>出力例（VS2019 Preview2）</h3>
<p><pre><code>256
000000308BAFF5D8
000000308BAFF5D8
true
false
</code></pre></p>
<h2>バージョン</h2>
<h3>言語</h3>
<ul>
<li>C++17</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>: 9.1 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
<li><a href="../../implementation.html#visual_cpp">Visual C++</a>: 2017 update 6 <span aria-label="検証済" role="img" title="検証済">✅</span></li>
</ul>
<h2>関連項目</h2>
<ul>
<li><code><a href="pool_resource.html">synchronized_pool_resource</a></code></li>
<li><code><a href="pool_resource.html">unsynchronized_pool_resource</a></code></li>
<li><code><a href="monotonic_buffer_resource.html">monotonic_buffer_resource</a></code></li>
<li><code><a href="new_delete_resource.html">new_delete_resource</a></code></li>
<li><code><a href="null_memory_resource.html">null_memory_resource</a></code></li>
</ul>
<h2>参照</h2>
<ul>
<li><a href="https://faithandbrave.hateblo.jp/entry/2016/08/08/170454" target="_blank">C++1z 多相アロケータとメモリプール - Faith and Brave - C++で遊ぼう </a></li>
<li><a href="https://cpplover.blogspot.com/2015/09/memoryresource.html" target="_blank">memory_resourceについて - 本の虫</a></li>
<li><a href="https://qiita.com/MitsutakaTakeda/items/48980faa9498c46b15b2" target="_blank">Polymorphic Allocator in C++17 - Qita</a></li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0220r1.html" target="_blank">P0220R1 Adopt Library Fundamentals V1 TS Components for C++17 (R1)</a></li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0337r0.html" target="_blank">P0337r0 | Delete operator= for polymorphic_allocator</a></li>
<li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4562.html#memory.resource.synop" target="_blank">Working Draft, C++ Extensions for Library Fundamentals, Version 2</a></li>
</ul></div>
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