{"id":541,"date":"2023-09-16T16:10:03","date_gmt":"2023-09-16T08:10:03","guid":{"rendered":""},"modified":"2023-09-17T00:41:54","modified_gmt":"2023-09-16T16:41:54","slug":"%e3%80%90c%e3%80%91%e5%a4%9a%e7%ba%bf%e7%a8%8b%e5%90%8c%e6%ad%a5","status":"publish","type":"post","link":"https:\/\/mushiming.com\/541.html","title":{"rendered":"\u3010C++\u3011\u591a\u7ebf\u7a0b\u540c\u6b65"},"content":{"rendered":"<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"display: none;\"> \n <path stroke-linecap=\"round\" d=\"M5,0 0,2.5 5,5z\" id=\"raphael-marker-block\" style=\"-webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"><\/path> \n<\/svg> <\/p>\n<p>\u7ebf\u7a0b\u95f4\u7684\u540c\u6b65\u65b9\u6cd5\u5927\u4f53\u53ef\u4ee5\u5206\u4e3a\u4e24\u7c7b\uff1a\u7528\u6237\u6a21\u5f0f\u548c\u5185\u6838\u6a21\u5f0f\u3002\u5185\u6838\u6a21\u5f0f\u5c31\u662f\u6307\u5229\u7528\u7cfb\u7edf\u5185\u6838\u5bf9\u8c61\u7684\u5355\u4e00\u6027\u6765\u8fdb\u884c\u540c\u6b65\uff0c\u4f7f\u7528\u65f6\u9700\u8981\u5207\u6362\u5185\u6838\u6001\u4e0e\u7528\u6237\u6001\uff0c\u800c\u7528\u6237\u6a21\u5f0f\u5c31\u662f\u4e0d\u9700\u8981\u5207\u6362\u5230\u5185\u6838\u6001\uff0c\u53ea\u5728\u7528\u6237\u6001\u5b8c\u6210\u64cd\u4f5c\u3002<\/p>\n<ul>\n<li>\u7528\u6237\u6a21\u5f0f\u4e0b\u7684\u65b9\u6cd5\u6709\uff1a\u539f\u5b50\u64cd\u4f5c\uff08\u4f8b\u5982\u4e00\u4e2a\u5355\u4e00\u7684\u5168\u5c40\u53d8\u91cf\uff09\u3001\u4e34\u754c\u533a\u3002\u7279\u70b9\u662f\uff1a\u540c\u6b65\u901f\u5ea6\u7279\u522b\u5feb\u3002<\/li>\n<li>\u5185\u6838\u6a21\u5f0f\u4e0b\u7684\u65b9\u6cd5\u6709\uff1a\u4e8b\u4ef6\u3001\u4fe1\u53f7\u91cf\u3001\u4e92\u65a5\u91cf\u3002\u540c\u6b65\u901f\u5ea6\u8f83\u6162\uff0c\u4f46\u9002\u7528\u6027\u6bd4\u8f83\u597d\u3002<\/li>\n<\/ul>\n<p>**\u4e34\u754c\u533a\uff1a**\u901a\u8fc7\u5bf9\u591a\u7ebf\u7a0b\u7684\u4e32\u884c\u5316\u6765\u8bbf\u95ee\u516c\u5171\u8d44\u6e90\u6216\u4e00\u6bb5\u4ee3\u7801\u3001\u901f\u5ea6\u5feb\uff0c\u9002\u5408\u63a7\u5236\u6570\u636e\u8bbf\u95ee\u3002<\/p>\n<p>**\u4e92\u65a5\u91cf\uff1a**\u4e3a\u534f\u8c03\u5171\u540c\u5bf9\u4e00\u4e2a\u5171\u4eab\u8d44\u6e90\u7684\u5355\u72ec\u8bbf\u95ee\u800c\u8bbe\u8ba1\u7684\u3002<\/p>\n<p>**\u4fe1\u53f7\u91cf\uff1a**\u4e3a\u63a7\u5236\u4e00\u4e2a\u5177\u6709\u6709\u9650\u6570\u91cf\u7528\u6237\u8d44\u6e90\u800c\u8bbe\u8ba1\u7684\u3002<\/p>\n<p>**\u4e8b\u4ef6\uff1a**\u7528\u6765\u901a\u77e5\u7ebf\u7a0b\u6709\u4e00\u4e9b\u65f6\u95f4\u5df2\u53d1\u751f\uff0c\u4ece\u800c\u542f\u52a8\u540e\u7ee7\u4efb\u52a1\u7684\u5f00\u59cb\u3002<\/p>\n<h3>1 atomic<\/h3>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">atomic&lt;int&gt; num{0};\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n\n    \/\/\u68c0\u67e5\u662f\u5426\u65e0\u9501\u7684\n    std::cout &lt;&lt; \"num.is_lock_free():\" &lt;&lt; num.is_lock_free() &lt;&lt; endl;\n\n    num.store(10);                             \/\/\u5b58\u50a8\u503c\n    std::cout &lt;&lt; \"num:\" &lt;&lt; num.load() &lt;&lt; endl; \/\/\u8bfb\u53d6\u503c\n\n    int a = num.exchange(100); \/\/\u4ea4\u6362\u503c,\u8fd4\u56de\u539f\u6765\u7684\u503c\n    std::cout &lt;&lt; \"num:\" &lt;&lt; num.load() &lt;&lt; endl;\n\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<p>atomic\u5e76\u4e0d\u80fd\u4fdd\u8bc1\u7c7b\u578bT\u662f\u65e0\u9501\u7684\uff0c\u53e6\u5916\u4e0d\u540c\u5e73\u53f0\u7684\u5904\u7406\u5668\u5904\u7406\u65b9\u5f0f\u4e0d\u540c\uff0c\u4e5f\u4e0d\u80fd\u4fdd\u8bc1\u5fc5\u5b9a\u65e0\u9501\uff0c\u6240\u4ee5\u8be5\u7c7b\u578b\u90fd\u4f1a\u6709is_lock_free() \u51fd\u6570\u6765\u5224\u65ad\u662f\u5426\u65e0\u9501\u3002<\/p>\n<p>\u6709\u4e00\u4e2a\u6bd4\u8f83\u7279\u6b8a\u7684\u539f\u5b50\u7c7b\u578b\u662fatomic_flag\uff0c\u56e0\u4e3aatomic_flag\u4e0e\u5176\u4ed6\u539f\u5b50\u7c7b\u578b\u4e0d\u540c\uff0c\u5b83\u662f\u65e0\u9501\u7684\uff0c\u5373\u7ebf\u7a0b\u5bf9\u5176\u8bbf\u95ee\u4e0d\u9700\u8981\u52a0\u9501\uff0c\u800c\u5176\u4ed6\u7684\u539f\u5b50\u7c7b\u578b\u4e0d\u4e00\u5b9a\u662f\u65e0\u9501\u7684\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">atomic_flag flag = ATOMIC_FLAG_INIT; \/\/\u521d\u59cb\u5316\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n\n    \/\/\u4e4b\u524d\u8fd8\u672a\u8bbe\u7f6e\u6807\u5fd7,\u6240\u4ee5\u8c03\u7528\u7684\u65f6\u5019\u8fd4\u56defalse,\u7136\u540e\u8bbe\u7f6e\u4e86\u6807\u5fd7\n    std::cout &lt;&lt; \"ret:\" &lt;&lt; flag.test_and_set() &lt;&lt; endl;\n    \/\/\u518d\u6b21\u8c03\u7528\u7684\u65f6\u5019\u5df2\u7ecf\u8bbe\u7f6e\u8fc7\u6807\u5fd7,\u6240\u4ee5\u8fd4\u56detrue\n    std::cout &lt;&lt; \"ret:\" &lt;&lt; flag.test_and_set() &lt;&lt; endl;\n\n    flag.clear(); \/\/\u6e05\u9664\u6807\u5fd7\n    \/\/\u6e05\u9664\u6807\u5fd7\u540e,\u8fd4\u56de\u503c\u4e3afalse,\u5e76\u4e14\u8bbe\u7f6e\u4e86\u6807\u5fd7\n    std::cout &lt;&lt; \"ret:\" &lt;&lt; flag.test_and_set() &lt;&lt; endl;\n    \/\/\u8bbe\u7f6e\u6807\u5fd7\u540e,\u8fd4\u56de\u503c\u4e3atrue\n    std::cout &lt;&lt; \"ret:\" &lt;&lt; flag.test_and_set() &lt;&lt; endl;\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<h3>2 \u4e34\u754c\u533a<\/h3>\n<p>\u5728Linux\u5e73\u53f0\u4e0b\uff0c\u6ca1\u6709\u4e34\u754c\u533a\u7684\u6982\u5ff5\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">#include &lt;windows.h&gt;\nCRITICAL_SECTION cs; \/\/\u5b9a\u4e49\u4e34\u754c\u533a\u5bf9\u8c61\nvoid foo()\n{\n    EnterCriticalSection(&amp;cs);\n    \/* code \u516c\u5171\u8d44\u6e90\u4ee3\u7801*\/\n    LeaveCriticalSection(&amp;cs);\n}\n\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n    InitializeCriticalSection(&amp;cs); \/\/\u521d\u59cb\u5316\u4e34\u754c\u533a\n    thread th(foo);\n    thread th(foo);\n    InitializeCriticalSection(&amp;cs); \/\/\u521d\u59cb\u5316\u4e34\u754c\u533a\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<h3>3 \u4e92\u65a5\u91cf<\/h3>\n<p>\u5728C++11\u4e2d\u88ab\u547d\u540d\u4e3aMutex\uff0c\u6240\u6709\u5176\u76f8\u5173\u7684\u7c7b\u548c\u51fd\u6570\u90fd\u5728\u5934\u6587\u4ef6mutex\u4e2d\u3002\u4e00\u5171\u6709\u56db\u79cd\u4e92\u65a5\u5143\u7c7b\uff0c\u5206\u522b\u662f\uff1a<\/p>\n<ul>\n<li>**std::mutex;**\u6700\u57fa\u672c\u7684\u4e92\u65a5\u5143\u7c7b<\/li>\n<li>**std::recursive_mutex;**\u9012\u5f52Mutex\u7c7b\uff08\u540c\u4e00\u7ebf\u7a0b\u53ef\u4ee5\u5bf9\u4e92\u65a5\u91cf\u591a\u6b21\u4e0a\u9501\uff0c\u6765\u83b7\u5f97\u5bf9\u4e92\u65a5\u91cf\u5bf9\u8c61\u7684\u591a\u5c42\u6240\u6709\u6743\uff09\u3002<\/li>\n<li>**std::timed_mutex;**\u5b9a\u65f6Mutex\u7c7b\u3002<\/li>\n<li>**std::recursive_timed_mutex;**\u5b9a\u65f6\u9012\u5f52Mutex\u7c7b<\/li>\n<\/ul>\n<p>\u4e0a\u8ff0\u56db\u79cd\u4e92\u65a5\u91cf\u5143\u7c7b\u90fd\u6709\u4e00\u4e2a\u6210\u5458\u51fd\u6570lock\u548cunlock\u6765\u5b9e\u73b0\u9501\u5b9a\u4e0e\u89e3\u9501\u7684\u64cd\u4f5c\u3002<\/p>\n<p>\u9664\u6b64\u4e4b\u5916\uff0c\u8fd8\u6709\u4e24\u79cdlock\u7c7b\uff0c\u5206\u522b\u662f\uff1a<\/p>\n<ul>\n<li>**std::lock_guard;**\u8fd9\u4e2a\u7c7b\u7684\u4f7f\u7528\u7c7b\u4f3c\u667a\u80fd\u6307\u9488\uff0c\u53ef\u4ee5\u9500\u6bc1\u65f6\u81ea\u52a8\u89e3\u9501\uff1b<\/li>\n<li>**std::unique_lock;**\u8fd9\u4e2a\u7c7b\u4e0e1\u7528\u6cd5\u76f8\u540c\uff0c\u4f46\u63d0\u4f9b\u4e86\u66f4\u7075\u6d3b\u7684\u4e0a\u9501\u548c\u89e3\u9501\u63a7\u5236\uff0c\u540c\u65f6\u4e5f\u66f4\u5360\u8d44\u6e90\u3002<\/li>\n<\/ul>\n<h4>3.1 std::mutex\u7c7b<\/h4>\n<ul>\n<li>\u6784\u9020\u51fd\u6570\uff0c<code>std::mutex<\/code>\u4e0d\u5141\u8bb8\u62f7\u8d1d\u6784\u9020\uff0c\u4e5f\u4e0d\u5141\u8bb8 move \u62f7\u8d1d\uff0c\u6700\u521d\u4ea7\u751f\u7684 mutex \u5bf9\u8c61\u662f\u5904\u4e8e unlocked \u72b6\u6001\u7684\u3002<\/li>\n<li>lock()\uff0c\u8c03\u7528\u7ebf\u7a0b\u5c06\u9501\u4f4f\u8be5\u4e92\u65a5\u91cf\u3002\u7ebf\u7a0b\u8c03\u7528\u8be5\u51fd\u6570\u4f1a\u53d1\u751f\u4e0b\u97623 \u79cd\u60c5\u51b5\uff1a\n<ol>\n<li>\u5982\u679c\u8be5\u4e92\u65a5\u91cf\u5f53\u524d\u6ca1\u6709\u88ab\u9501\u4f4f\uff0c\u5219\u8c03\u7528\u7ebf\u7a0b\u5c06\u8be5\u4e92\u65a5\u91cf\u9501\u4f4f\uff0c\u76f4\u5230\u8c03\u7528 unlock\u4e4b\u524d\uff0c\u8be5\u7ebf\u7a0b\u4e00\u76f4\u62e5\u6709\u8be5\u9501\u3002<\/li>\n<li>\u5982\u679c\u5f53\u524d\u4e92\u65a5\u91cf\u88ab\u5176\u4ed6\u7ebf\u7a0b\u9501\u4f4f\uff0c\u5219\u5f53\u524d\u7684\u8c03\u7528\u7ebf\u7a0b\u88ab\u963b\u585e\u4f4f\u3002<\/li>\n<li>\u5982\u679c\u5f53\u524d\u4e92\u65a5\u91cf\u88ab\u5f53\u524d\u8c03\u7528\u7ebf\u7a0b\u9501\u4f4f\uff0c\u5219\u4f1a\u4ea7\u751f\u6b7b\u9501(deadlock)\u3002<\/li>\n<\/ol>\n<\/li>\n<li><code>unlock()<\/code>\uff0c \u89e3\u9501\uff0c\u91ca\u653e\u5bf9\u4e92\u65a5\u91cf\u7684\u6240\u6709\u6743\u3002<\/li>\n<li>try_lock()\uff0c\u5c1d\u8bd5\u9501\u4f4f\u4e92\u65a5\u91cf\uff0c\u5982\u679c\u4e92\u65a5\u91cf\u88ab\u5176\u4ed6\u7ebf\u7a0b\u5360\u6709\uff0c\u5219\u5f53\u524d\u7ebf\u7a0b\u4e5f\u4e0d\u4f1a\u88ab\u963b\u585e\u3002\u7ebf\u7a0b\u8c03\u7528\u8be5\u51fd\u6570\u4e5f\u4f1a\u51fa\u73b0\u4e0b\u97623 \u79cd\u60c5\u51b5\uff1a\n<ol>\n<li>\u5982\u679c\u5f53\u524d\u4e92\u65a5\u91cf\u6ca1\u6709\u88ab\u5176\u4ed6\u7ebf\u7a0b\u5360\u6709\uff0c\u5219\u8be5\u7ebf\u7a0b\u9501\u4f4f\u4e92\u65a5\u91cf\uff0c\u76f4\u5230\u8be5\u7ebf\u7a0b\u8c03\u7528 unlock \u91ca\u653e\u4e92\u65a5\u91cf\u3002<\/li>\n<li>\u5982\u679c\u5f53\u524d\u4e92\u65a5\u91cf\u88ab\u5176\u4ed6\u7ebf\u7a0b\u9501\u4f4f\uff0c\u5219\u5f53\u524d\u8c03\u7528\u7ebf\u7a0b\u8fd4\u56de false\uff0c\u800c\u5e76\u4e0d\u4f1a\u88ab\u963b\u585e\u6389\u3002<\/li>\n<li>\u5982\u679c\u5f53\u524d\u4e92\u65a5\u91cf\u88ab\u5f53\u524d\u8c03\u7528\u7ebf\u7a0b\u9501\u4f4f\uff0c\u5219\u4f1a\u4ea7\u751f\u6b7b\u9501(deadlock)\u3002<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">void foo()\n{\n    if(mtx.try_lock())\n    {\n         \/*\u516c\u5171\u8d44\u6e90code*\/\n         mtx.unlock();\n    }\n}\n#include &lt;mutex&gt;\nstd::mutex mtx;\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n    thread th1(foo);\n    thread th2(foo);\n    th1.join();\n    th2.join();\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<h4>3.2 lock_guard<\/h4>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">#include &lt;mutex&gt;\nstd::mutex mtx;\nvoid foo()\n{\n    \/\/\u4f7f\u7528mutex\u5bf9\u8c61\u5b9a\u4e49\u4e00\u4e2a\u5c40\u90e8\u7684lock_guard\u5bf9\u8c61\n    std::lock_guard&lt;std::mutex&gt; lock(mtx);\n    \/*\u516c\u5171\u8d44\u6e90code*\/\n    \/\/\u53ea\u6709\u7b49\u5230\u8be5lock_guard\u5bf9\u8c61\u9500\u6bc1\u540e\u624d\u80fd\u89e3\u9501\n}\n\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n    thread th1(foo);\n    thread th2(foo);\n    th1.join();\n    th2.join();\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<h4>3.3 unique_lock<\/h4>\n<p>lock_guard\u672c\u8eab\u5e76\u6ca1\u6709\u63d0\u4f9b\u67b7\u9501\u548c\u89e3\u9501\u7684\u63a5\u53e3\uff0c\u667a\u80fd\u4fdd\u8bc1\u518d\u6790\u6784\u7684\u65f6\u5019\u6267\u884c\u89e3\u9501\u64cd\u4f5c\uff0c\u4e0d\u591f\u7075\u6d3b\u3002<\/p>\n<p>\u4f46\u662funique_lock\u63d0\u4f9b\u4e86lock()\u548cunlock()\u63a5\u53e3\uff0c\u80fd\u8bb0\u5f55\u73b0\u5728\u5904\u4e8e\u4e0a\u9501\u8fd8\u662f\u89e3\u9501\u72b6\u6001\uff0c\u5728\u6790\u6784\u7684\u65f6\u5019\uff0c\u4f1a\u6839\u636e\u5f53\u524d\u72b6\u6001\u6765\u51b3\u5b9a\u662f\u5426\u9700\u8981\u89e3\u9501\u3002\u7136\u800c\u8fd9\u662f\u6709\u4ee3\u4ef7\u7684\uff0c\u56e0\u4e3a\u5b83\u5185\u90e8\u9700\u8981\u7ef4\u62a4\u9501\u7684\u72b6\u6001\uff0c\u6240\u4ee5\u6548\u7387\u8981\u6bd4lock_guard\u4f4e\u4e00\u70b9\uff0c\u5728lock_guard\u80fd\u89e3\u51b3\u95ee\u9898\u7684\u65f6\u5019\uff0c\u5c31\u7528lock_guard\uff0c\u53cd\u4e4b\u4f7f\u7528unique_lock\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">#include &lt;mutex&gt;\nstd::mutex mtx;\nvoid foo()\n{\n    \/\/\u4f7f\u7528mutex\u5bf9\u8c61\u5b9a\u4e49\u4e00\u4e2a\u5c40\u90e8\u7684lock_guard\u5bf9\u8c61\n    std::unique_lock&lt;std::mutex&gt; lock(mtx);\n    \/*do something1 code*\/\n\n    lock.unlock();\n    \/*do others *\/\n\n    lock.lock();\n    \/*do something2 code*\/\n}\n\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n    thread th1(foo);\n    thread th2(foo);\n    th1.join();\n    th2.join();\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<h4>3.4 std::condition_variable<\/h4>\n<p>condition_variable\u662f\u4e00\u4e2a\u7c7b\uff0c\u642d\u914d\u4e92\u65a5\u91cfmutex\u6765\u7528\uff0c\u8fd9\u4e2a\u7c7b\u4e3b\u8981\u6709wait\u51fd\u6570\u548cnotify\u51fd\u6570\u3002\u7a0b\u5e8f\u8fd0\u884c\u5230wait\u51fd\u6570\u7684\u65f6\u5019\u4f1a\u5148\u5728\u6b64\u963b\u585e\uff0c\u7136\u540e\u81ea\u52a8unlock\uff0c\u90a3\u4e48\u5176\u4ed6\u7ebf\u7a0b\u5728\u62ff\u5230\u9501\u4ee5\u540e\u5c31\u4f1a\u5f80\u4e0b\u8fd0\u884c\uff0c\u5f53\u8fd0\u884c\u5230notify\u51fd\u6570\u7684\u65f6\u5019\uff0c\u5c31\u4f1a\u5524\u9192wait\u51fd\u6570\uff0c\u7136\u540e\u81ea\u52a8lock\u5e76\u7ee7\u7eed\u8fd0\u884c\u3002<\/p>\n<p>\u5f53\u7136wait\u51fd\u6570\u8fd8\u6709\u7b2c\u4e8c\u4e2a\u53c2\u6570\uff0c\u8fd9\u4e2a\u53c2\u6570\u63a5\u6536\u4e00\u4e2a\u5e03\u5c14\u7c7b\u578b\u7684\u503c\uff0c\u5f53\u8fd9\u4e2a\u5e03\u5c14\u7c7b\u578b\u7684\u503c\u4e3afalse\u7684\u65f6\u5019\u7ebf\u7a0b\u5c31\u4f1a\u88ab\u963b\u585e\u5728\u8fd9\u91cc\uff0c\u53ea\u6709\u5f53\u8be5\u7ebf\u7a0b\u88ab\u5524\u9192\u4e4b\u540e\uff0c\u4e14\u7b2c\u4e8c\u53c2\u6570\u4e3atrue\u624d\u4f1a\u5f80\u4e0b\u8fd0\u884c\u3002<\/p>\n<p>notify_one\u51fd\u6570\u6bcf\u6b21\u53ea\u80fd\u5524\u9192\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u90a3\u4e48notify_all\u51fd\u6570\u7684\u4f5c\u7528\u5c31\u662f\u53ef\u4ee5\u5524\u9192\u6240\u6709\u7684\u7ebf\u7a0b\uff0c\u4f46\u662f\u6700\u7ec8\u80fd\u62a2\u593a\u9501\u7684\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u6216\u8005\u8bf4\u6709\u591a\u4e2a\u7ebf\u7a0b\u5728wait\uff0c\u4f46\u662f\u7528notify_one\u53bb\u5524\u9192\u5176\u4e2d\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u90a3\u4e48\u8fd9\u4e9b\u7ebf\u7a0b\u5c31\u51fa\u73b0\u4e86\u53bb\u4e89\u593a\u4e92\u65a5\u91cf\u7684\u4e00\u4e2a\u60c5\u51b5\uff0c\u90a3\u4e48\u6700\u7ec8\u6ca1\u6709\u83b7\u5f97\u9501\u7684\u63a7\u5236\u6743\u7684\u7ebf\u7a0b\u5c31\u4f1a\u518d\u6b21\u56de\u5230\u963b\u585e\u7684\u72b6\u6001\uff0c\u90a3\u4e48\u5bf9\u4e8e\u8fd9\u4e9b\u6ca1\u6709\u62a2\u5230\u63a7\u5236\u6743\u7684\u8fd9\u4e2a\u8fc7\u7a0b\u5c31\u53eb\u505a\u865a\u5047\u5524\u9192\u3002\u90a3\u4e48\u5bf9\u4e8e\u865a\u5047\u5524\u9192\u7684\u89e3\u51b3\u65b9\u6cd5\u5c31\u662f\u52a0\u4e00\u4e2awhile\u5faa\u73af\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">#include &lt;mutex&gt;\n#include &lt;cstdlib&gt;\nstd::mutex mtx;\nstd::condition_variable cv;\nstd::queue&lt;int&gt; que;\n\nvoid consumer()\n{\n    while (true)\n    {\n        std::unique_lock&lt;std::mutex&gt; lck(mtx);\n        \/\/ while (que.size() == 0) \/\/\u5f53\u961f\u5217\u4e3a\u7a7a\u7684\u65f6\u5019\uff0c\u9700\u8981\u7b49\u5f85\n        \/\/ {\n        \/\/     cv.wait(lck);\n        \/\/ }\n        \/*\u4e0a\u8ff0\u5199\u6cd5\u8fd9\u6837\u4e5f\u53ef\u4ee5\u3002\u5f53\u961f\u5217\u4e0d\u4e3a\u7a7a\u4e14\u7ebf\u7a0b\u88ab\u5524\u9192\u624d\u53ef\u4ee5\u7ee7\u7eed\u6267\u884c\u3002\n        cv.wait(lck, []()\n                { return que.size() != 0; });\n        *\/\n        int temp = que.front();\n        std::cout &lt;&lt; \"read the first element:\" &lt;&lt; temp &lt;&lt; \" from the queue\" &lt;&lt; endl;\n        que.pop();\n    }\n}\n\nvoid producer()\n{\n    srand((int)time(0)); \/\/\u968f\u673a\u79cd\u5b50\n    while (true)\n    {\n        {\n            std::unique_lock&lt;std::mutex&gt; lck(mtx);\n            int temp = rand() % 100;\n            que.push(temp);\n            std::cout &lt;&lt; \"write an element:\" &lt;&lt; temp &lt;&lt; \" to the queue\" &lt;&lt; endl;\n        }\/\/\u6ce8\u610f\u8fd9\u4e2a\u4f5c\u7528\u57df\uff0c\u4e3a\u4e86\u5c31\u662funlock\uff0c\u4e0d\u53ef\u4ee5\u7701\u3002\n        \/\/\u7136\u540e\u518d\u53bb\u5524\u9192\u3002\n        cv.notify_all();\n    }\n}\n\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n    thread th1(producer);\n    thread th2(consumer);\n    th1.join();\n    th2.join();\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<h3>4 \u4fe1\u53f7\u91cf\uff08Semaphore\uff09<\/h3>\n<p>\u5b9a\u4e49\u4e8e\u5934\u6587\u4ef6&lt;semaphore.h&gt;\uff0c\u4fe1\u53f7\u91cf\u662f\u4e00\u79cd\u8f7b\u91cf\u7684\u540c\u6b65\u673a\u5236\uff0c\u7528\u4e8e\u5236\u7ea6\u5bf9\u5171\u4eab\u8d44\u6e90\u7684\u5e76\u53d1\u8bbf\u95ee\uff08\u63a7\u5236\u7ebf\u7a0b\u7684\u5e76\u53d1\u6570\u91cf\uff09\u3002\u5728\u53ef\u4ee5\u4f7f\u7528\u4e24\u8005\u65f6\uff0c\u4fe1\u53f7\u91cf\u80fd\u6bd4\u6761\u4ef6\u53d8\u91cf\u66f4\u6709\u6548\u7387\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">\/\/ \u521d\u59cb\u5316\n#include&lt;semaphore.h&gt;\nint sem_init(sem_t *sem,int pshared,unsigned int value);\n\/*\n\u529f\u80fd \u521b\u5efa\u4e00\u4e2a\u4fe1\u53f7\u91cf\u5e76\u521d\u59cb\u5316\u5b83\u7684\u503c\uff0c\u4e00\u4e2a\u65e0\u540d\u4fe1\u53f7\u91cf\u5728\u88ab\u4f7f\u7528\u524d\u5fc5\u987b\u521d\u59cb\u5316\n\u53c2\u6570 sem \u4fe1\u53f7\u91cf\u5730\u5740  \n     pshared  \u7b49\u4e8e0 \u4fe1\u53f7\u91cf\u5728\u7ebf\u7a0b\u95f4\u5171\u4eab   \u4e0d\u7b49\u4e8e0 \u4fe1\u53f7\u5728\u8fdb\u7a0b\u95f4\u5171\u4eab\n     value \u4fe1\u53f7\u91cf\u7684\u521d\u59cb\u503c\n\u8fd4\u56de \u6210\u529f 0    \u5931\u8d25 -1\n\n*\/\n\n\n\/\/ \u9500\u6bc1\n#include&lt;semaphore,h&gt;\nint sem_destroy(sem_t *sem);\n\/*\n\u529f\u80fd \u5220\u9664sem\u6807\u8bc6\u7684\u4fe1\u53f7\u91cf\n\u53c2\u6570 sem \u4fe1\u53f7\u91cf\u5730\u5740\n\u8fd4\u56de \u6210\u529f 0    \u5931\u8d25 -1\n*\/\n\n\n\/\/ P\u64cd\u4f5c(\u51cf1)\n#include&lt;semaphore.h&gt;\nint sem_wait(sem_t *sem);\n\/*\n\u529f\u80fd \u5c06\u4fe1\u53f7\u91cf\u7684\u503c\u51cf1\uff0c\u64cd\u4f5c\u524d\uff0c\u5148\u68c0\u67e5\u4fe1\u53f7\u91cf(sem)\u7684\u503c\u662f\u5426\u4e3a0\uff0c\u82e5\u4e3a0\uff0c\u5219\u963b\u585e\uff0c\u76f4\u5230\u4fe1\u53f7\u91cf\u5927\u4e8e0\u518d\u51cf\n\u53c2\u6570 sem \u4fe1\u53f7\u91cf\u5730\u5740\n\u8fd4\u56de \u6210\u529f 0   \u5931\u8d25 -1\n*\/\n\n\/\/ \u975e\u963b\u585e\u51cf1\nint sem_trywait(sem_t *sem);\n\/\/ \u4ee5\u975e\u963b\u585e\u7684\u65b9\u5f0f\u6765\u5bf9\u4fe1\u53f7\u91cf\u8fdb\u884c\u51cf1\u64cd\u4f5c\n\/\/ \u82e5\u64cd\u4f5c\u524d\uff0c\u4fe1\u53f7\u91cf\u7684\u503c\u7b49\u4e8e0\uff0c\u5219\u5bf9\u4fe1\u53f7\u91cf\u7684\u64cd\u4f5c\u5931\u8d25\uff0c\u51fd\u6570\u7acb\u5373\u8fd4\u56de\n\n\/\/ \u9650\u65f6\u51cf1\nint sem_timedwait(sem_t *sem,const struct timespec *abs_timeout);\n\/\/ \u9650\u65f6\u5c1d\u8bd5\u5c06\u4fe1\u53f7\u91cf\u7684\u503c\u51cf1\n\/\/ abs_timeout \u7edd\u5bf9\u65f6\u95f4\n\n\n\/\/ V\u64cd\u4f5c(\u52a01)\n#include&lt;semaphore.h&gt;\nint sem_post(sem_t *sem);\n\/*\n\u529f\u80fd \u5c06\u4fe1\u53f7\u91cf\u7684\u503c\u52a01\uff0c\u5e76\u53d1\u51fa\u4fe1\u53f7\u5524\u9192\u7b49\u5f85\u7ebf\u7a0b(sem_wait());\n\u53c2\u6570 sem \u4fe1\u53f7\u91cf\u5730\u5740\n\u8fd4\u56de \u6210\u529f 0    \u5931\u8d25 -1\n*\/\n\n\n\/\/ \u83b7\u53d6\u4fe1\u53f7\u91cf\u7684\u503c\n#include&lt;semaphore.h&gt;\nint sem_getvalue(sem_t *sem,int *val);\n\/*\n\u529f\u80fd \u83b7\u53d6sem\u6807\u8bc6\u7684\u4fe1\u53f7\u91cf\u7684\u503c\uff0c\u4fdd\u5b58\u5728val\u4e2d\n\u53c2\u6570 sem \u4fe1\u53f7\u91cf\u5730\u5740   val \u4fdd\u5b58\u4fe1\u53f7\u91cf\u503c\u7684\u5730\u5740\n\u8fd4\u56de \u6210\u529f 0     \u5931\u8d25 -1\n*\/\n<\/code><\/pre>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">\/\/\u5728\u4e24\u4e2a\u51fd\u6570\u4e2d\u6309\u987a\u5e8f\u6253\u5370\u5947\u6570\u5076\u6570\n#include &lt;semaphore.h&gt;\nsem_t oddSem;\nsem_t evenSem;\n\nvoid getOdd()\n{\n    for (size_t i = 0; i &lt; 100; i++)\n    {\n        if (i % 2 != 0)\n        {\n            sem_wait(&amp;oddSem);\/\/-1 \u64cd\u4f5c \u5982\u679c\u64cd\u4f5c\u524d\u4e3a0\u5219\u963b\u585e\u3002\n            std::cout &lt;&lt; \"threadID:\" &lt;&lt; this_thread::get_id() &lt;&lt; \" getOdd:\" &lt;&lt; i &lt;&lt; endl;\n            sem_post(&amp;evenSem);\/\/+1\u64cd\u4f5c \u901a\u77e5even\u6253\u5370\u3002\n        }\n    }\n}\n\nvoid getEven()\n{\n    for (size_t i = 0; i &lt; 100; i++)\n    {\n        if (i % 2 == 0)\n        {\n            sem_wait(&amp;evenSem);\/\/-1\u64cd\u4f5c\uff0c\u5982\u679c\u64cd\u4f5c\u524d\u4e3a0\u5219\u963b\u585e\u3002\n            std::cout &lt;&lt; \"threadID:\" &lt;&lt; this_thread::get_id() &lt;&lt; \" getEven:\" &lt;&lt; i &lt;&lt; endl;\n            sem_post(&amp;oddSem);\/\/+1\u64cd\u4f5c\uff0c\u901a\u77e5odd\u6253\u5370\n        }\n    }\n}\n\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n\n    sem_init(&amp;oddSem,0,0);\n    sem_init(&amp;evenSem,0,1);\/\/\u4ece0\u5f00\u59cb\u6253\u5370\uff0c\u6240\u4ee5\u521d\u59cb\u503c\u4e3a1.\n\n    thread th1(getOdd);\n    thread th2(getEven);\n    th1.join();\n    th2.join();\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n<h3>5 \u4e8b\u4ef6<\/h3>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-c++\">HANDLE event = NULL;\n\nvoid m_raise()\n{\n    for (size_t i = 0; i &lt; 10; i++)\n    {\n        \/* code *\/\n        std::cout &lt;&lt; \"threadID:\" &lt;&lt; this_thread::get_id() &lt;&lt;__FUNCTION__&lt;&lt; i &lt;&lt; endl;\n        if(i==5)\n        {\n            \/\/\u6fc0\u6d3b\u4e8b\u4ef6\u3002\n            SetEvent(event);\n        }\n    }\n}\n\nvoid receive()\n{\n    \/\/\u5982\u679c\u4e8b\u4ef6\u4e3a\u6fc0\u6d3b\u72b6\u6001\u5219\u76f4\u63a5\u6267\u884c\u3002\n    \/\/\u5426\u5219\u963b\u585e\u76f4\u5230\u4e8b\u4ef6\u88ab\u6fc0\u6d3b\u3002\n    WaitForSingleObject(event,INFINITE);\n    for (size_t i = 0; i &lt; 10; i++)\n    {\n        \/* code *\/\n        std::cout &lt;&lt; \"threadID:\" &lt;&lt; this_thread::get_id() &lt;&lt;__FUNCTION__&lt;&lt; i &lt;&lt; endl;\n    }\n}\n\nint main(int, char **)\n{\n    std::cout &lt;&lt; \"========boot=======\" &lt;&lt; endl;\n    \/\/\u521d\u59cb\u5316\u4e8b\u4ef6\n    event = CreateEvent(NULL, FALSE, TRUE, NULL);  \n\tResetEvent(event);\/\/\u8bbe\u7f6e\u4e8b\u4ef6\u72b6\u6001\u4e3a\u672a\u6fc0\u6d3b\u72b6\u6001\u3002\n\n    thread th1(receive);\n    thread th2(m_raise);\n    th1.join();\n    th2.join();\n    std::cout &lt;&lt; \"========over=======\" &lt;&lt; endl;\n}\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"\u3010C++\u3011\u591a\u7ebf\u7a0b\u540c\u6b65\u7ebf\u7a0b\u95f4\u7684\u540c\u6b65\u65b9\u6cd5\u5927\u4f53\u53ef\u4ee5\u5206\u4e3a\u4e24\u7c7b\uff1a\u7528\u6237\u6a21\u5f0f\u548c\u5185\u6838\u6a21\u5f0f\u3002\u5185\u6838\u6a21\u5f0f\u5c31\u662f\u6307\u5229\u7528\u7cfb\u7edf\u5185\u6838\u5bf9\u8c61\u7684\u5355\u4e00\u6027\u6765\u8fdb\u884c\u540c...","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"_links":{"self":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/541"}],"collection":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/comments?post=541"}],"version-history":[{"count":0,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/541\/revisions"}],"wp:attachment":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/media?parent=541"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/categories?post=541"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/tags?post=541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}