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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>aligned_alloc</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-memory.html">memory</a>&lrm; | <a href="cpp-memory-c.html">c</a></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code><a href="cpp-header-cstdlib.html">&lt;cstdlib&gt;</a></code></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span><span class="sy2">*</span> aligned_alloc<span class="br0">(</span> <a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> alignment, <a href="cpp-types-size_t.html"><span class="kw100">std::<span class="me2">size_t</span></span></a> size <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></td>
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<p>&#20998;&#37197; <code>size</code> &#23383;&#33410;&#30340;&#26410;&#21021;&#22987;&#21270;&#23384;&#20648;&#65292;&#30001; <code>alignment</code> &#25351;&#23450;&#20854;&#23545;&#40784;&#12290; <code>size</code> &#21442;&#25968;&#24517;&#39035;&#26159; <code>alignment</code> &#30340;&#25972;&#25968;&#20493;&#12290;</p>
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<p>&#35201;&#27714;&#19979;&#21015;&#20989;&#25968;&#26159;&#32447;&#31243;&#23433;&#20840;&#30340;&#65306;</p>
<ul>
<li><a href="cpp-memory-new-operator_new.html"><tt>operator new</tt></a> &#21450; <a href="cpp-memory-new-operator_delete.html"><tt>operator delete</tt></a> &#30340;&#24211;&#29256;&#26412;</li>
<li>&#20840;&#23616; <a href="cpp-memory-new-operator_new.html"><tt>operator new</tt></a> &#19982; <a href="cpp-memory-new-operator_delete.html"><tt>operator delete</tt></a> &#30340;&#29992;&#25143;&#26367;&#25442;&#29256;&#26412;</li>
<li><span class="t-lc"><a href="cpp-memory-c-calloc.html">std::calloc</a></span> &#12289; <span class="t-lc"><a href="cpp-memory-c-malloc.html">std::malloc</a></span> &#12289; <span class="t-lc"><a href="cpp-memory-c-realloc.html">std::realloc</a></span> <span class="t-rev-inl t-since-cxx17"><span>&#12289; <span class="t-lc"><strong class="selflink">std::aligned_alloc</strong></span></span> <span><span class="t-mark-rev t-since-cxx17">(C++17 &#36215;)</span></span></span> &#12289; <span class="t-lc"><a href="cpp-memory-c-free.html">std::free</a></span></li>
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<p>&#23545;&#36825;&#20123;&#20998;&#37197;&#25110;&#35299;&#20998;&#37197;&#29305;&#23450;&#23384;&#20648;&#21333;&#20803;&#30340;&#20989;&#25968;&#35843;&#29992;&#20197;&#21333;&#29420;&#20840;&#24207;&#20986;&#29616;&#65292;&#24182;&#19988;&#22312;&#27492;&#39034;&#24207;&#20013;&#65292;&#27599;&#20010;&#35299;&#20998;&#37197;&#35843;&#29992;<a href="cpp-atomic-memory_order.html">&#20808;&#21457;&#29983;&#20110;</a>&#19979;&#20010;&#20998;&#37197;&#65288;&#33509;&#23384;&#22312;&#65289;&#12290;</p>
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<td><span class="t-mark-rev t-since-cxx11">(C++11 &#36215;)</span></td>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
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<td>alignment</td>
<td>-</td>
<td>&#25351;&#23450;&#23545;&#40784;&#12290;&#24517;&#39035;&#26159;&#23454;&#29616;&#25903;&#25345;&#30340;&#21512;&#27861;&#23545;&#40784;&#12290;</td>
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<td>size</td>
<td>-</td>
<td>&#20998;&#37197;&#30340;&#23383;&#33410;&#25968;&#12290; <code>alignment</code> &#30340;&#25972;&#25968;&#20493;&#12290;</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#25104;&#21151;&#26102;&#65292;&#36820;&#22238;&#25351;&#21521;&#26032;&#20998;&#37197;&#20869;&#23384;&#36215;&#22987;&#30340;&#25351;&#38024;&#12290;&#20026;&#36991;&#20813;&#20869;&#23384;&#27844;&#28431;&#65292;&#36820;&#22238;&#30340;&#25351;&#38024;&#24517;&#39035;&#30001; <span class="t-lc"><a href="cpp-memory-c-free.html">std::free</a></span> &#25110; <span class="t-lc"><a href="cpp-memory-c-realloc.html">std::realloc</a></span> &#35299;&#20998;&#37197;&#12290;</p>
<p>&#22833;&#36133;&#26102;&#65292;&#36820;&#22238;&#31354;&#25351;&#38024;&#12290;</p>
<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">&#27880;&#24847;</span></h3>
<p>&#20256;&#36882;&#19981;&#26159; <code>alignment</code> &#25972;&#25968;&#20493;&#30340; <code>size</code> &#25110;&#19981;&#21463;&#23454;&#29616;&#25903;&#25345;&#25110;&#38750;&#27861;&#30340; <code>alignment</code> &#23548;&#33268;&#20989;&#25968;&#22833;&#36133;&#24182;&#36820;&#22238;&#31354;&#25351;&#38024;&#65288; C11 &#21018;&#21457;&#24067;&#26102;&#65292;&#26366;&#25351;&#23450;&#27492;&#24773;&#20917;&#20026;&#26410;&#23450;&#20041;&#34892;&#20026;&#65292;&#36825;&#20026; DR 460 &#25152;&#32416;&#27491;&#65289;&#12290;</p>
<p>&#20316;&#20026;&ldquo;&#23454;&#29616;&#25903;&#25345;&rdquo;&#35201;&#27714;&#30340;&#20363;&#23376;&#65292; POSIX &#20989;&#25968; <a rel="nofollow" class="external text" href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_memalign.html">posix_memalign</a> &#25509;&#21463;&#20219;&#20309;&#26159;&#20108;&#30340;&#24130;&#19988;&#20026; <code>sizeof(void*)</code> &#20493;&#25968;&#30340; <code>alignment</code> &#65292;&#32780;&#22522;&#20110; POSIX &#30340; <code>aligned_alloc</code> &#23454;&#29616;&#32487;&#25215;&#27492;&#35201;&#27714;&#12290;</p>
<p>&#24120;&#35268;&#30340; <span class="t-lc"><a href="cpp-memory-c-malloc.html">std::malloc</a></span> &#20998;&#37197;&#36866;&#29992;&#20110;&#20219;&#20309;&#23545;&#35937;&#30340;&#22823;&#23567;&#30340;&#20869;&#23384;&#65288;&#23454;&#38469;&#19978;&#65292;&#24847;&#21619;&#30528;&#20869;&#23384;&#23545;&#40784;&#21040; <span class="t-c"><span class="mw-geshi cpp source-cpp">alignof<span class="br0">(</span><a href="cpp-types-max_align_t.html"><span class="kw104">std::<span class="me2">max_align_t</span></span></a><span class="br0">)</span></span></span> &#65289;&#12290;&#27492;&#20989;&#25968;&#36866;&#29992;&#20110;&#36807;&#23545;&#40784;&#20998;&#37197;&#65292;&#20363;&#22914;&#23545; SSE &#12289;&#32531;&#23384;&#32447;&#25110; VM &#39029;&#36793;&#30028;&#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
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<pre class="de1"><span class="co2">#include &lt;cstdio&gt;</span>
<span class="co2">#include &lt;cstdlib&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<span class="kw4">int</span><span class="sy2">*</span> p1 <span class="sy1">=</span> <span class="kw1">static_cast</span><span class="sy1">&lt;</span><span class="kw4">int</span><span class="sy2">*</span><span class="sy1">&gt;</span><span class="br0">(</span><a href="cpp-memory-c-malloc.html"><span class="kw759">std::<span class="me2">malloc</span></span></a><span class="br0">(</span><span class="nu0">10</span><span class="sy2">*</span>sizeof <span class="sy2">*</span>p1<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-c-fprintf.html"><span class="kw1844">std::<span class="me2">printf</span></span></a><span class="br0">(</span><span class="st0">&quot;default-aligned address: %p<span class="es1">\n</span>&quot;</span>, <span class="kw1">static_cast</span><span class="sy1">&lt;</span><span class="kw4">void</span><span class="sy2">*</span><span class="sy1">&gt;</span><span class="br0">(</span>p1<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-memory-c-free.html"><span class="kw762">std::<span class="me2">free</span></span></a><span class="br0">(</span>p1<span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">int</span><span class="sy2">*</span> p2 <span class="sy1">=</span> <span class="kw1">static_cast</span><span class="sy1">&lt;</span><span class="kw4">int</span><span class="sy2">*</span><span class="sy1">&gt;</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">aligned_alloc</span><span class="br0">(</span><span class="nu0">1024</span>, <span class="nu0">10</span><span class="sy2">*</span>sizeof <span class="sy2">*</span>p2<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-c-fprintf.html"><span class="kw1844">std::<span class="me2">printf</span></span></a><span class="br0">(</span><span class="st0">&quot;1024-byte aligned address: %p<span class="es1">\n</span>&quot;</span>, <span class="kw1">static_cast</span><span class="sy1">&lt;</span><span class="kw4">void</span><span class="sy2">*</span><span class="sy1">&gt;</span><span class="br0">(</span>p2<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-memory-c-free.html"><span class="kw762">std::<span class="me2">free</span></span></a><span class="br0">(</span>p2<span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
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<p>&#21487;&#33021;&#30340;&#36755;&#20986;&#65306;</p>
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<pre class="de1">default-aligned address: 0x2221c20
1024-byte aligned address: 0x2222400</pre></div>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<div><a href="cpp-types-aligned_storage.html"><span class="t-lines"><span>aligned_storage</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div>
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<td>&#23450;&#20041;&#36866;&#20110;&#29992;&#20316;&#32473;&#23450;&#22823;&#23567;&#30340;&#31867;&#22411;&#30340;&#26410;&#21021;&#22987;&#21270;&#23384;&#20648;&#30340;&#31867;&#22411;<br />
<span class="t-mark">(&#31867;&#27169;&#26495;)</span></td>
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