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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>counting_semaphore, <span style="font-size:0.7em; line-height:130%">std::</span>binary_semaphore</h1>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code><a href="cpp-header-semaphore.html">&lt;semaphore&gt;</a></code></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span><a href="cpp-types-ptrdiff_t.html"><span class="kw101">std::<span class="me2">ptrdiff_t</span></span></a> LeastMaxValue <span class="sy1">=</span> <span class="coMULTI">/* implementation-defined */</span><span class="sy1">&gt;</span><br />
<span class="kw1">class</span> counting_semaphore<span class="sy4">;</span></span></div>
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<td>(1)</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">using</span> binary_semaphore <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">counting_semaphore</span><span class="sy1">&lt;</span><span class="nu0">1</span><span class="sy1">&gt;</span><span class="sy4">;</span></span></div>
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<td>(2)</td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<div class="t-li1"><span class="t-li">1)</span> <code>counting_semaphore</code> &#26159;&#19968;&#20010;&#36731;&#37327;&#21516;&#27493;&#20803;&#20214;&#65292;&#33021;&#25511;&#21046;&#23545;&#20849;&#20139;&#36164;&#28304;&#30340;&#35775;&#38382;&#12290;&#19981;&#21516;&#20110; <span class="t-lc"><a href="cpp-thread-mutex.html">std::mutex</a></span> &#12289; <code>counting_semaphore</code> &#20801;&#35768;&#21516;&#19968;&#36164;&#28304;&#26377;&#22810;&#20110;&#19968;&#20010;&#21516;&#26102;&#35775;&#38382;&#65292;&#33267;&#23569;&#20801;&#35768; <code>LeastMaxValue</code> &#20010;&#21516;&#26102;&#30340;&#35775;&#38382;&#32773;&#33509;<code>LeastMaxValue</code> &#20026;&#36127;&#21017;&#31243;&#24207;&#20026;&#35884;&#26500;&#12290;</div>
<div class="t-li1"><span class="t-li">2)</span> <code>binary_semaphore</code> &#26159; <span class="t-lc">std::counting_semaphore</span> &#30340;&#29305;&#21270;&#30340;&#21035;&#21517;&#65292;&#20854; <code>LeastMaxValue</code> &#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="nu0">1</span></span></span> &#12290;&#23454;&#29616;&#21487;&#33021;&#23558; <code>binary_semaphore</code> &#23454;&#29616;&#24471;&#27604; <span class="t-lc">std::counting_semaphore</span> &#30340;&#40664;&#35748;&#23454;&#29616;&#26356;&#39640;&#25928;&#12290;</div>
<p><code>counting_semaphore</code> &#21547;&#26377;&#30001;&#26500;&#36896;&#20989;&#25968;&#21021;&#22987;&#21270;&#30340;&#20869;&#37096;&#35745;&#25968;&#22120;&#12290;&#30001;&#35843;&#29992; <span class="t-c"><span class="mw-geshi cpp source-cpp">acquire<span class="br0">(</span><span class="br0">)</span></span></span> &#19982;&#30456;&#20851;&#26041;&#27861;&#20943;&#23569;&#27492;&#35745;&#25968;&#22120;&#65292;&#32780;&#23427;&#36890;&#36807;&#35843;&#29992; <span class="t-c"><span class="mw-geshi cpp source-cpp">release<span class="br0">(</span><span class="br0">)</span></span></span> &#22686;&#21152;&#12290;&#35745;&#25968;&#22120;&#20026;&#38646;&#26102;&#65292; <span class="t-c"><span class="mw-geshi cpp source-cpp">acquire<span class="br0">(</span><span class="br0">)</span></span></span> &#38459;&#22622;&#35813;&#35745;&#25968;&#22120;&#30452;&#33267;&#23427;&#22686;&#21152;&#65292;&#20294; <span class="t-c"><span class="mw-geshi cpp source-cpp">try_acquire<span class="br0">(</span><span class="br0">)</span></span></span> &#19981;&#38459;&#22622;&#65307; <span class="t-c"><span class="mw-geshi cpp source-cpp">try_acquire_for<span class="br0">(</span><span class="br0">)</span></span></span> &#19982; <span class="t-c"><span class="mw-geshi cpp source-cpp">try_acquire_until<span class="br0">(</span><span class="br0">)</span></span></span> &#38459;&#22622;&#30452;&#33267;&#35745;&#25968;&#22120;&#22686;&#21152;&#25110;&#21040;&#36798;&#26102;&#38480;&#12290;</p>
<p>&#31867;&#20284; <span class="t-lc"><a href="cpp-thread-condition_variable.html">std::condition_variable</a></span> &#30340; <span class="t-c"><span class="mw-geshi cpp source-cpp">wait<span class="br0">(</span><span class="br0">)</span></span></span> &#65292; <code>counting_semaphore</code> &#30340; <span class="t-c"><span class="mw-geshi cpp source-cpp">try_acquire<span class="br0">(</span><span class="br0">)</span></span></span> &#21487;&#33021;&#34394;&#20551;&#22320;&#22833;&#36133;&#12290;</p>
<p><code>std::counting_semaphore</code> &#30340;&#29305;&#21270;&#38750;<a href="cpp-named_req-DefaultConstructible.html"><span style="font-style:italic">&#21487;&#40664;&#35748;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(DefaultConstructible)</span></a> &#12289;<a href="cpp-named_req-CopyConstructible.html"><span style="font-style:italic">&#21487;&#22797;&#21046;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(CopyConstructible)</span></a> &#12289;<a href="cpp-named_req-MoveConstructible.html"><span style="font-style:italic">&#21487;&#31227;&#21160;&#26500;&#36896;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(MoveConstructible)</span></a> &#12289;<a href="cpp-named_req-CopyAssignable.html"><span style="font-style:italic">&#21487;&#22797;&#21046;&#36171;&#20540;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(CopyAssignable)</span></a> &#25110;<a href="cpp-named_req-MoveAssignable.html"><span style="font-style:italic">&#21487;&#31227;&#21160;&#36171;&#20540;</span> <span style="font-family: Georgia, &#39;DejaVu Serif&#39;, serif; font-style:italic">(MoveAssignable)</span></a> &#12290;</p>
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">&#25104;&#21592;&#20989;&#25968;</span></h3>
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<div><a href="cpp-thread-counting_semaphore-counting_semaphore.html"><span class="t-lines"><span>(&#26500;&#36896;&#20989;&#25968;)</span></span></a></div>
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<td>&#26500;&#36896; <code>counting_semaphore</code><br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><a href="https://zh.cppreference.com/w/cpp/thread/counting_semaphore/%7Ecounting_semaphore" title="cpp/thread/counting semaphore/~counting semaphore"><span class="t-lines"><span>(&#26512;&#26500;&#20989;&#25968;)</span></span></a></div>
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<td>&#38144;&#27585; <code>counting_semaphore</code><br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><span class="t-lines"><span>operator=</span></span></div>
<div><span class="t-lines"><span><span class="t-cmark">[&#34987;&#21024;&#38500;]</span></span></span></div>
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<td><code>counting_semaphore</code> &#19981;&#21487;&#36171;&#20540;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<h5><span class="mw-headline" id=".E6.93.8D.E4.BD.9C">&#25805;&#20316;</span></h5>
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<div><a href="cpp-thread-counting_semaphore-release.html"><span class="t-lines"><span>release</span></span></a></div>
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<td>&#22686;&#21152;&#20869;&#37096;&#35745;&#25968;&#22120;&#24182;&#38500;&#38459;&#33719;&#21462;&#32773;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><a href="cpp-thread-counting_semaphore-acquire.html"><span class="t-lines"><span>acquire</span></span></a></div>
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<td>&#20943;&#23569;&#20869;&#37096;&#35745;&#25968;&#22120;&#25110;&#38459;&#22622;&#21040;&#30452;&#33267;&#33021;&#22914;&#27492;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><a href="cpp-thread-counting_semaphore-try_acquire.html"><span class="t-lines"><span>try_acquire</span></span></a></div>
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<td>&#23581;&#35797;&#20943;&#23569;&#20869;&#37096;&#35745;&#25968;&#22120;&#32780;&#19981;&#38459;&#22622;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><a href="cpp-thread-counting_semaphore-try_acquire_for.html"><span class="t-lines"><span>try_acquire_for</span></span></a></div>
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<td>&#23581;&#35797;&#20943;&#23569;&#20869;&#37096;&#35745;&#25968;&#22120;&#65292;&#33267;&#22810;&#38459;&#22622;&#19968;&#27573;&#26102;&#38271;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><a href="cpp-thread-counting_semaphore-try_acquire_until.html"><span class="t-lines"><span>try_acquire_until</span></span></a></div>
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<td>&#23581;&#35797;&#20943;&#23569;&#20869;&#37096;&#35745;&#25968;&#22120;&#65292;&#38459;&#22622;&#30452;&#33267;&#19968;&#20010;&#26102;&#38388;&#28857;<br />
<span class="t-mark">(&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<h5><span class="mw-headline" id=".E5.B8.B8.E9.87.8F">&#24120;&#37327;</span></h5>
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<div><a href="cpp-thread-counting_semaphore-max.html"><span class="t-lines"><span>max</span></span></a></div>
<div><span class="t-lines"><span><span class="t-cmark">[&#38745;&#24577;]</span></span></span></div>
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<td>&#36820;&#22238;&#20869;&#37096;&#35745;&#25968;&#22120;&#30340;&#26368;&#22823;&#21487;&#33021;&#20540;<br />
<span class="t-mark">(&#20844;&#24320;&#38745;&#24577;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">&#27880;&#35299;</span></h3>
<p>&#22914;&#20854;&#21517;&#25152;&#31034;&#65292; <code>LeastMaxValue</code> &#26159;<i>&#26368;&#23567;</i>&#30340;&#26368;&#22823;&#20540;&#65292;&#32780;&#38750;<i>&#23454;&#38469;</i>&#26368;&#22823;&#20540;&#12290;&#20174;&#32780; <span class="t-c"><span class="mw-geshi cpp source-cpp">max<span class="br0">(</span><span class="br0">)</span></span></span> &#33021;&#20135;&#29983;&#22823;&#20110; <code>LeastMaxValue</code> &#30340;&#20540;&#12290;</p>
<p>&#19981;&#21516;&#20110; <span class="t-lc"><a href="cpp-thread-mutex.html">std::mutex</a></span> &#65292; <code>counting_semaphore</code> &#19981;&#25414;&#32465;&#21040;&#25191;&#34892;&#32447;&#31243;&mdash;&mdash;&#33021;&#22312;&#19981;&#21516;&#20110;&#37322;&#25918;&#20449;&#21495;&#37327;&#30340;&#32447;&#31243;&#33719;&#21462;&#35813;&#20449;&#21495;&#37327;&#12290;&#33021;&#21516;&#26102;&#36827;&#34892; <code>counting_semaphore</code> &#19978;&#30340;&#25152;&#26377;&#25805;&#20316;&#32780;&#26080;&#38656;&#32852;&#31995;&#21040;&#20219;&#20309;&#29305;&#23450;&#30340;&#25191;&#34892;&#32447;&#31243;&#65292;&#38500;&#20102;&#19981;&#33021;&#21516;&#26102;&#25191;&#34892;&#65292;&#20294;&#33021;&#22312;&#19968;&#20010;&#19981;&#21516;&#30340;&#32447;&#31243;&#19978;&#25191;&#34892;&#26512;&#26500;&#20989;&#25968;&#12290;</p>
<p>&#20449;&#21495;&#37327;&#20134;&#24120;&#29992;&#20110;&#21457;&#20449;/&#25552;&#37266;&#32780;&#38750;&#20114;&#26021;&#65292;&#36890;&#36807;&#21021;&#22987;&#21270;&#35813;&#20449;&#21495;&#37327;&#20026; <span class="t-c"><span class="mw-geshi cpp source-cpp">&#8203;<span class="nu0">0</span>&#8203;</span></span> &#20174;&#32780;&#38459;&#22622;&#23581;&#35797; <span class="t-c"><span class="mw-geshi cpp source-cpp">acquire<span class="br0">(</span><span class="br0">)</span></span></span> &#30340;&#25509;&#25910;&#32773;&#65292;&#30452;&#33267;&#25552;&#37266;&#32773;&#36890;&#36807;&#35843;&#29992; <span class="t-c"><span class="mw-geshi cpp source-cpp">release<span class="br0">(</span>n<span class="br0">)</span></span></span> &ldquo;&#21457;&#20449;&rdquo;&#12290;&#22312;&#27492;&#26041;&#38754;&#21487;&#25226;&#20449;&#21495;&#37327;&#24403;&#20316; <span class="t-lc"><a href="cpp-thread-condition_variable.html">std::condition_variable</a></span> &#30340;&#26367;&#29992;&#21697;&#65292;&#36890;&#24120;&#23427;&#26377;&#26356;&#22909;&#30340;&#24615;&#33021;&#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;iostream&gt;</span>
<span class="co2">#include &lt;thread&gt;</span>
<span class="co2">#include &lt;chrono&gt;</span>
<span class="co2">#include &lt;semaphore&gt;</span>
<span class="kw1">using</span> <span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">literals</span><span class="sy4">;</span>
<span class="co1">// &#20840;&#23616;&#20108;&#20803;&#20449;&#21495;&#37327;&#23454;&#20363;</span>
<span class="co1">// &#35774;&#32622;&#23545;&#35937;&#35745;&#25968;&#20026;&#38646;</span>
<span class="co1">// &#23545;&#35937;&#22312;&#26410;&#34987;&#21457;&#20449;&#29366;&#24577;</span>
std<span class="sy4">::</span><span class="me2">binary_semaphore</span> smphSignal<span class="br0">(</span><span class="nu0">0</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">void</span> ThreadProc<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<span class="co1">// &#36890;&#36807;&#23581;&#35797;&#20943;&#23569;&#20449;&#21495;&#37327;&#30340;&#35745;&#25968;&#31561;&#24453;&#26469;&#33258;&#20027;&#31243;&#24207;&#30340;&#20449;&#21495;</span>
smphSignal.<span class="me1">acquire</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// &#27492;&#35843;&#29992;&#38459;&#22622;&#30452;&#33267;&#20449;&#21495;&#37327;&#30340;&#35745;&#25968;&#34987;&#20174;&#20027;&#31243;&#24207;&#22686;&#21152;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;[thread] Got the signal&quot;</span> <span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-endl.html"><span class="kw1791">std::<span class="me2">endl</span></span></a><span class="sy4">;</span> <span class="co1">// &#22238;&#24212;&#28040;&#24687;</span>
<span class="co1">// &#31561;&#24453; 3 &#31186;&#20197;&#27169;&#20223;&#26576;&#31181;&#32447;&#31243;&#27491;&#22312;&#36827;&#34892;&#30340;&#24037;&#20316;</span>
<a href="cpp-thread-sleep_for.html"><span class="kw2149">std::<span class="me2">this_thread</span><span class="sy4">::</span><span class="me2">sleep_for</span></span></a><span class="br0">(</span>3s<span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;[thread] Send the signal<span class="es1">\n</span>&quot;</span><span class="sy4">;</span> <span class="co1">// &#28040;&#24687;</span>
<span class="co1">// &#23545;&#20027;&#31243;&#24207;&#22238;&#22797;&#21457;&#20449;</span>
smphSignal.<span class="me1">release</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<span class="co1">// &#21019;&#24314;&#26576;&#20010;&#32972;&#26223;&#24037;&#20316;&#32447;&#31243;&#65292;&#23427;&#23558;&#38271;&#26399;&#23384;&#22312;</span>
std<span class="sy4">::</span><span class="me2">jthread</span> thrWorker<span class="br0">(</span>ThreadProc<span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;[main] Send the signal<span class="es1">\n</span>&quot;</span><span class="sy4">;</span> <span class="co1">// &#28040;&#24687;</span>
<span class="co1">// &#36890;&#36807;&#22686;&#21152;&#20449;&#21495;&#37327;&#30340;&#35745;&#25968;&#23545;&#24037;&#20316;&#32447;&#31243;&#21457;&#20449;&#20197;&#24320;&#22987;&#24037;&#20316;</span>
smphSignal.<span class="me1">release</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// release() &#21518;&#38543; acquire() &#21487;&#20197;&#38459;&#27490;&#24037;&#20316;&#32447;&#31243;&#33719;&#21462;&#20449;&#21495;&#37327;&#65292;&#25152;&#20197;&#28155;&#21152;&#24310;&#36831;&#65306;</span>
<a href="cpp-thread-sleep_for.html"><span class="kw2149">std::<span class="me2">this_thread</span><span class="sy4">::</span><span class="me2">sleep_for</span></span></a><span class="br0">(</span>50ms<span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// &#36890;&#36807;&#35797;&#22270;&#20943;&#23569;&#20449;&#21495;&#37327;&#30340;&#35745;&#25968;&#31561;&#24453;&#30452;&#33267;&#24037;&#20316;&#32447;&#31243;&#23436;&#25104;&#24037;&#20316;</span>
smphSignal.<span class="me1">acquire</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;[main] Got the signal<span class="es1">\n</span>&quot;</span><span class="sy4">;</span> <span class="co1">// &#22238;&#24212;&#28040;&#24687;</span>
<span class="br0">}</span></pre></div>
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<p>&#36755;&#20986;&#65306;</p>
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<div class="text source-text">
<pre class="de1">[main] Send the signal
[thread] Got the signal
[thread] Send the signal
[main] Got the signal</pre></div>
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