{"id":4478,"date":"2020-12-29T17:36:48","date_gmt":"2020-12-29T09:36:48","guid":{"rendered":"https:\/\/yanjingang.com\/blog\/?p=4478"},"modified":"2021-01-11T10:35:37","modified_gmt":"2021-01-11T02:35:37","slug":"c%e6%99%ba%e8%83%bd%e6%8c%87%e9%92%88unique_ptr-%e3%80%81shared_ptr%e3%80%81weak_ptr%e3%80%81auto_ptr","status":"publish","type":"post","link":"https:\/\/yanjingang.com\/blog\/?p=4478","title":{"rendered":"C++\u667a\u80fd\u6307\u9488(unique_ptr \u3001shared_ptr\u3001weak_ptr\u3001auto_ptr)"},"content":{"rendered":"<h1>\u4e00\u3001\u6982\u8ff0<\/h1>\n<p><strong>\u667a\u80fd\u6307\u9488\uff1a<\/strong><strong>\u667a\u80fd\u6307\u9488\u662f\u4e00\u4e2a\u7c7b\uff0c\u7528\u6765\u5b58\u50a8\u6307\u9488\uff08\u6307\u5411\u52a8\u6001\u5206\u914d\u5bf9\u8c61\u4e5f\u5c31\u662f\u5806\u4e2d\u5bf9\u8c61\u7684\u7684\u6307\u9488\uff09\u3002<\/strong><\/p>\n<p>\u5728\u5b9e\u9645\u7684 C++ \u5f00\u53d1\u4e2d\uff0c\u6211\u4eec\u7ecf\u5e38\u4f1a\u9047\u5230\u8bf8\u5982\u7a0b\u5e8f\u8fd0\u884c\u4e2d\u7a81\u7136\u5d29\u6e83\u3001\u7a0b\u5e8f\u8fd0\u884c\u6240\u7528\u5185\u5b58\u8d8a\u6765\u8d8a\u591a\u6700\u7ec8\u4e0d\u5f97\u4e0d\u91cd\u542f\u7b49\u95ee\u9898\uff0c\u8fd9\u4e9b\u95ee\u9898\u5f80\u5f80\u90fd\u662f\u5185\u5b58\u8d44\u6e90\u7ba1\u7406\u4e0d\u5f53\u9020\u6210\u7684\u3002\u6bd4\u5982\uff1a<\/p>\n<ul>\n<li>\u6709\u4e9b\u5185\u5b58\u8d44\u6e90\u5df2\u7ecf\u88ab\u91ca\u653e\uff0c\u4f46\u6307\u5411\u5b83\u7684\u6307\u9488\u5e76\u6ca1\u6709\u6539\u53d8\u6307\u5411\uff08\u6210\u4e3a\u4e86\u91ce\u6307\u9488\uff09\uff0c\u5e76\u4e14\u540e\u7eed\u8fd8\u5728\u4f7f\u7528\uff1b<\/li>\n<li>\u6709\u4e9b\u5185\u5b58\u8d44\u6e90\u5df2\u7ecf\u88ab\u91ca\u653e\uff0c\u540e\u671f\u53c8\u8bd5\u56fe\u518d\u91ca\u653e\u4e00\u6b21\uff08\u91cd\u590d\u91ca\u653e\u540c\u4e00\u5757\u5185\u5b58\u4f1a\u5bfc\u81f4\u7a0b\u5e8f\u8fd0\u884c\u5d29\u6e83\uff09\uff1b<\/li>\n<li>\u6ca1\u6709\u53ca\u65f6\u91ca\u653e\u4e0d\u518d\u4f7f\u7528\u7684\u5185\u5b58\u8d44\u6e90\uff0c\u9020\u6210\u5185\u5b58\u6cc4\u6f0f\uff0c\u7a0b\u5e8f\u5360\u7528\u7684\u5185\u5b58\u8d44\u6e90\u8d8a\u6765\u8d8a\u591a\u3002<\/li>\n<\/ul>\n<p>\u9488\u5bf9\u4ee5\u4e0a\u8fd9\u4e9b\u60c5\u51b5\uff0c\u5f88\u591a\u7a0b\u5e8f\u5458\u8ba4\u4e3a C++ \u8bed\u8a00\u5e94\u8be5\u63d0\u4f9b\u66f4\u53cb\u597d\u7684\u5185\u5b58\u7ba1\u7406\u673a\u5236\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u5c06\u7cbe\u529b\u96c6\u4e2d\u4e8e\u5f00\u53d1\u9879\u76ee\u7684\u5404\u4e2a\u529f\u80fd\u4e0a\u3002<\/p>\n<p>\u4e8b\u5b9e\u4e0a\uff0c\u663e\u793a\u5185\u5b58\u7ba1\u7406\u7684\u66ff\u4ee3\u65b9\u6848\u5f88\u65e9\u5c31\u6709\u4e86\uff0c\u65e9\u5728 1959 \u5e74\u524d\u540e\uff0c\u5c31\u6709\u4eba\u63d0\u51fa\u4e86\u201c\u5783\u573e\u81ea\u52a8\u56de\u6536\u201d\u673a\u5236\u3002\u6240\u8c13\u5783\u573e\uff0c\u6307\u7684\u662f\u90a3\u4e9b\u4e0d\u518d\u4f7f\u7528\u6216\u8005\u6ca1\u6709\u4efb\u4f55\u6307\u9488\u6307\u5411\u7684\u5185\u5b58\u7a7a\u95f4\uff0c\u800c\u201c\u56de\u6536\u201d\u5219\u6307\u7684\u662f\u5c06\u8fd9\u4e9b\u201c\u5783\u573e\u201d\u6536\u96c6\u8d77\u6765\u4ee5\u4fbf\u518d\u6b21\u5229\u7528\u3002<\/p>\n<p>\u5982\u4eca\uff0c\u5783\u573e\u56de\u6536\u673a\u5236\u5df2\u7ecf\u5927\u884c\u5176\u9053\uff0c\u5f97\u5230\u4e86\u8bf8\u591a\u7f16\u7a0b\u8bed\u8a00\u7684\u652f\u6301\uff0c\u4f8b\u5982 Java\u3001Python\u3001C#\u3001PHP \u7b49\u3002\u800c C++ \u867d\u7136\u4ece\u6765\u6ca1\u6709\u516c\u5f00\u5f97\u652f\u6301\u8fc7\u5783\u573e\u56de\u6536\u673a\u5236\uff0c\u4f46 C++98\/03 \u6807\u51c6\u4e2d\uff0c\u652f\u6301\u4f7f\u7528 auto_ptr \u667a\u80fd\u6307\u9488\u6765\u5b9e\u73b0\u5806\u5185\u5b58\u7684\u81ea\u52a8\u56de\u6536\uff1bC++11 \u65b0\u6807\u51c6\u5728\u5e9f\u5f03 auto_ptr \u7684\u540c\u65f6\uff0c\u589e\u6dfb\u4e86 unique_ptr\u3001shared_ptr \u4ee5\u53ca weak_ptr \u8fd9 3 \u4e2a\u667a\u80fd\u6307\u9488\u6765\u5b9e\u73b0\u5806\u5185\u5b58\u7684\u81ea\u52a8\u56de\u6536\u3002<\/p>\n<p>\u6240\u8c13\u667a\u80fd\u6307\u9488\uff0c\u53ef\u4ee5\u4ece\u5b57\u9762\u4e0a\u7406\u89e3\u4e3a\u201c\u667a\u80fd\u201d\u7684\u6307\u9488\u3002\u5177\u4f53\u6765\u8bb2\uff0c\u667a\u80fd\u6307\u9488\u548c\u666e\u901a\u6307\u9488\u7684\u7528\u6cd5\u662f\u76f8\u4f3c\u7684\uff0c\u4e0d\u540c\u4e4b\u5904\u5728\u4e8e\uff0c\u667a\u80fd\u6307\u9488\u53ef\u4ee5\u5728\u9002\u5f53\u65f6\u673a\u81ea\u52a8\u91ca\u653e\u5206\u914d\u7684\u5185\u5b58\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u4f7f\u7528\u667a\u80fd\u6307\u9488\u53ef\u4ee5\u5f88\u597d\u5730\u907f\u514d\u201c\u5fd8\u8bb0\u91ca\u653e\u5185\u5b58\u800c\u5bfc\u81f4\u5185\u5b58\u6cc4\u6f0f\u201d\u95ee\u9898\u51fa\u73b0\u3002\u7531\u6b64\u53ef\u89c1\uff0cC++ \u4e5f\u9010\u6e10\u5f00\u59cb\u652f\u6301\u5783\u573e\u56de\u6536\u673a\u5236\u4e86\uff0c\u5c3d\u7ba1\u76ee\u524d\u652f\u6301\u7a0b\u5ea6\u8fd8\u6709\u9650\u3002<\/p>\n<blockquote><p>C++ \u667a\u80fd\u6307\u9488\u5e95\u5c42\u662f\u91c7\u7528\u5f15\u7528\u8ba1\u6570\u7684\u65b9\u5f0f\u5b9e\u73b0\u7684\u3002\u7b80\u5355\u7684\u7406\u89e3\uff0c\u667a\u80fd\u6307\u9488\u5728\u7533\u8bf7\u5806\u5185\u5b58\u7a7a\u95f4\u7684\u540c\u65f6\uff0c\u4f1a\u4e3a\u5176\u914d\u5907\u4e00\u4e2a\u6574\u5f62\u503c\uff08\u521d\u59cb\u503c\u4e3a 1\uff09\uff0c\u6bcf\u5f53\u6709\u65b0\u5bf9\u8c61\u4f7f\u7528\u6b64\u5806\u5185\u5b58\u65f6\uff0c\u8be5\u6574\u5f62\u503c +1\uff1b\u53cd\u4e4b\uff0c\u6bcf\u5f53\u4f7f\u7528\u6b64\u5806\u5185\u5b58\u7684\u5bf9\u8c61\u88ab\u91ca\u653e\u65f6\uff0c\u8be5\u6574\u5f62\u503c\u51cf 1\u3002\u5f53\u5806\u7a7a\u95f4\u5bf9\u5e94\u7684\u6574\u5f62\u503c\u4e3a 0 \u65f6\uff0c\u5373\u8868\u660e\u4e0d\u518d\u6709\u5bf9\u8c61\u4f7f\u7528\u5b83\uff0c\u8be5\u5806\u7a7a\u95f4\u5c31\u4f1a\u88ab\u91ca\u653e\u6389\u3002<\/p><\/blockquote>\n<p>\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5c06\u5206\u522b\u5bf9unique_ptr \u3001 shared_ptr\u4ee5\u53ca weak_ptr \u8fd9 3 \u4e2a\u667a\u80fd\u6307\u9488\u7684\u7279\u6027\u548c\u7528\u6cd5\u505a\u8be6\u7ec6\u7684\u8bb2\u89e3\u3002<\/p>\n<h1>\u4e8c\u3001unique_ptr<\/h1>\n<p>unique_ptr \u662fauto_ptr\u7684\u5347\u7ea7\u7248\uff0c\u5e76\u4e14auto_ptr\u5728c++11\u4e2d\u5df2\u7ecf\u5f03\u7528\u3002<\/p>\n<p>unique_ptr \u662f\u4e00\u4e2a\u72ec\u4eab\u6240\u6709\u6743\u7684\u667a\u80fd\u6307\u9488\uff1a<\/p>\n<p>1\u3001\u62e5\u6709\u5b83\u6307\u5411\u7684\u5bf9\u8c61<\/p>\n<p>2\u3001\u65e0\u6cd5\u8fdb\u884c\u590d\u5236\u6784\u9020\uff0c\u65e0\u6cd5\u8fdb\u884c\u590d\u5236\u8d4b\u503c\u64cd\u4f5c\u3002\u5373\u65e0\u6cd5\u4f7f\u4e24\u4e2aunique_ptr\u6307\u5411\u540c\u4e00\u4e2a\u5bf9\u8c61\u3002\u4f46\u662f\u53ef\u4ee5\u8fdb\u884c\u79fb\u52a8\u6784\u9020\u548c\u79fb\u52a8\u8d4b\u503c\u64cd\u4f5c<\/p>\n<p>3\u3001\u4fdd\u5b58\u6307\u5411\u67d0\u4e2a\u5bf9\u8c61\u7684\u6307\u9488\uff0c\u5f53\u5b83\u672c\u8eab\u88ab\u5220\u9664\u91ca\u653e\u7684\u65f6\u5019\uff0c\u4f1a\u4f7f\u7528\u7ed9\u5b9a\u7684\u5220\u9664\u5668\u91ca\u653e\u5b83\u6307\u5411\u7684\u5bf9\u8c61<\/p>\n<p>unique_ptr \u53ef\u4ee5\u5b9e\u73b0\u5982\u4e0b\u529f\u80fd\uff1a<\/p>\n<p>1\u3001\u4e3a\u52a8\u6001\u7533\u8bf7\u7684\u5185\u5b58\u63d0\u4f9b\u5f02\u5e38\u5b89\u5168<\/p>\n<p>2\u3001\u8bb2\u52a8\u6001\u7533\u8bf7\u7684\u5185\u5b58\u6240\u6709\u6743\u4f20\u9012\u7ed9\u67d0\u51fd\u6570<\/p>\n<p>3\u3001\u4ece\u67d0\u4e2a\u51fd\u6570\u8fd4\u56de\u52a8\u6001\u7533\u8bf7\u5185\u5b58\u7684\u6240\u6709\u6743<\/p>\n<p>4\u3001\u5728\u5bb9\u5668\u4e2d\u4fdd\u5b58\u6307\u9488<\/p>\n<p>5\u3001auto_ptr \u5e94\u8be5\u5177\u6709\u7684\u529f\u80fd<\/p>\n<p>\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u201c.\u201d\u64cd\u4f5c\u8bbf\u95ee\u6307\u9488\uff0c\u901a\u8fc7\u201c-&gt;\u201d\u6765\u8bbf\u95ee\u5b83\u6307\u5411\u7684\u5bf9\u8c61\uff0cshared_ptr \u662f\u4e00\u6837\u7684\u3002<\/p>\n<pre class=\"pure-highlightjs\"><code class=\"\">\/*\r\n * \u6d4b\u8bd5\u7c7b\r\n *\/\r\nclass String\r\n{\r\n  private:\r\n    char * str; \/\/\u5b58\u50a8\u6570\u636e\r\n    int len; \/\/\u5b57\u7b26\u4e32\u957f\u5ea6\r\n    void copyString(const String&amp; a){\r\n        if(this!=&amp;a){\r\n            delete[] str;\r\n            len=a.len;\r\n            str=new char[len+1];\r\n            strcpy(str, a.str);\r\n        }\r\n    }\r\n  public:\r\n    String(){ \/\/ \u9ed8\u8ba4\u6784\u9020\u51fd\u6570\r\n        len =0;\r\n        str = new char[len+1];\r\n        str[0]='0';\r\n        std::cout &lt;&lt; \"String() initialize: \" &lt;&lt; str &lt;&lt; std::endl;\r\n    };\r\n    String(const char* s){ \/\/\u6784\u9020\u51fd\u6570\r\n        len = strlen(s);\r\n        str = new char[len + 1];\r\n        strcpy(str, s);\r\n        std::cout &lt;&lt; \"String(char* s) initialize: \" &lt;&lt; str &lt;&lt; std::endl;\r\n    }\r\n    String(const String&amp; a){\r\n        std::cout &lt;&lt; \"String(String&amp; a) copy initialize: \" &lt;&lt; str &lt;&lt; std::endl;\r\n        copyString(a);\r\n    }\r\n    String&amp; operator=(const String&amp; a)\r\n    {\r\n        std::cout &lt;&lt; \"operator=(String&amp; a) copy assign: \" &lt;&lt; str &lt;&lt; std::endl;\r\n        copyString(a);\r\n        return *this;\r\n    }\r\n    ~String(){ \/\/ \u6790\u6784\u51fd\u6570\r\n        std::cout &lt;&lt; \"~String() destroy: \" &lt;&lt; str &lt;&lt; std::endl;\r\n        delete[] str;\r\n    };\r\n    friend std::ostream &amp; operator &lt;&lt; (std::ostream &amp; os,const String&amp; st){\r\n        os &lt;&lt; st.str;\r\n        return os;\r\n    }\r\n};\r\n\/\/ shared_ptr\u6d4b\u8bd5\r\nString* new_string(){\r\n    return new String(\"*\");  \/\/ \u8c01\u8be5\u8d1f\u8d23\u91ca\u653e\u8fd9\u4e2aS\uff1f\r\n};\r\nstd::shared_ptr&lt;String&gt; new_string_autoptr(){\r\n    return std::shared_ptr&lt;String&gt;(new String(\"shared_ptr\")); \/\/ \u663e\u5f0f\u4f20\u9012\u8d1f\u8d23\u91ca\u653e\u8fd9\u4e2aS\r\n}\r\n\r\n\/*\r\n * main\r\n *\/\r\nint main(int argc, char* argv[]){\r\n    \/\/ unique_ptr\r\n    LOG(INFO) &lt;&lt; \"unique_ptr:\" &lt;&lt; std::endl;\r\n    std::unique_ptr&lt;String&gt; p1(new String(\"unique_ptr1\"));\r\n    std::unique_ptr&lt;String&gt; p2(new String(\"unique_ptr2\"));\r\n    std::cout &lt;&lt; \"p1=\" &lt;&lt; p1 &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"p2=\" &lt;&lt; p2 &lt;&lt; std::endl;\r\n    \/\/p1.release();\r\n    \/\/p1.reset();\r\n    p1 = std::move(p2); \/\/move\u4f1a\u89e6\u53d1p1\u539f\u5bf9\u8c61\u7684\u81ea\u52a8\u9500\u6bc1\uff0c\u5e76\u5c06p2\u6307\u5411\u5bf9\u8c61\u6307\u9488\u8f6c\u79fb\u7ed9p1\r\n    std::cout &lt;&lt; \"p1=\" &lt;&lt; p1 &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"p2=\" &lt;&lt; p2 &lt;&lt; std::endl;\r\n    if (p2 == nullptr){\r\n        std::cout &lt;&lt; \"unique_ptr2 is nullptr\" &lt;&lt; std::endl;\r\n    }\r\n\r\n    String *p = p1.release();   \/\/p1\u667a\u80fd\u6307\u9488\u8ba1\u6570-1\uff0c\u5e76\u5c06\u6307\u9488\u8f6c\u79fb\u7ed9p\u666e\u901a\u6307\u9488\uff08p\u666e\u901a\u6307\u9488\u5fc5\u987b\u901a\u8fc7delete\u6216\u6258\u7ba1\u7ed9\u667a\u80fd\u6307\u9488\u91ca\u653e\uff09\r\n    std::cout &lt;&lt; \"p1=\" &lt;&lt; p1 &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"p=\" &lt;&lt; p &lt;&lt; std::endl;\r\n\r\n    p2.reset(p);    \/\/p\u666e\u901a\u6307\u9488\u88abp2\u667a\u80fd\u6307\u9488\u6258\u7ba1\r\n    std::cout &lt;&lt; \"p2=\" &lt;&lt; p2 &lt;&lt; std::endl;\r\n    \/\/std::unique_ptr&lt;String&gt; p3(p);    \/\/ERROR! \u540c\u4e00\u666e\u901a\u6307\u9488\u4e0d\u80fd\u540c\u65f6\u4e3a\u591a\u4e2a\u667a\u80fd\u6307\u9488\u8d4b\u503c\uff0c\u4f1a\u5bfc\u81f4\u6790\u6784\u5f02\u5e38\r\n\r\n    std::cout &lt;&lt; \"-------main end\" &lt;&lt; std::endl;\r\n    return 0;\r\n}\r\n\r\n\/\/\u8fd0\u884c\u7ed3\u679c\uff1a\r\nI1229 18:07:25.701352 175566272 main.cc:402] unique_ptr:\r\nString(char* s) initialize: unique_ptr1\r\nString(char* s) initialize: unique_ptr2\r\np1=0x7fcb3f408920\r\np2=0x7fcb3f408960\r\n~String() destroy: unique_ptr1   \/\/move\u4f1a\u89e6\u53d1p1\u539f\u5bf9\u8c61\u7684\u81ea\u52a8\u9500\u6bc1\uff0c\u5e76\u5c06p2\u6307\u5411\u5bf9\u8c61\u6307\u9488\u8f6c\u79fb\u7ed9p1\r\np1=0x7fcb3f408960\r\np2=0x0\r\nunique_ptr2 is nullptr\r\np1=0x0      \/\/p1\u667a\u80fd\u6307\u9488\u8ba1\u6570-1\uff0c\u5e76\u5c06\u6307\u9488\u8f6c\u79fb\u7ed9p\u666e\u901a\u6307\u9488\r\np=0x7fcb3f408960\r\np2=0x7fcb3f408960   \/\/p\u666e\u901a\u6307\u9488\u88abp2\u667a\u80fd\u6307\u9488\u6258\u7ba1\r\n-------main end\r\n~String() destroy: unique_ptr2   \/\/p2\u667a\u80fd\u6307\u9488\u81ea\u52a8\u9500\u6bc1<\/code><\/pre>\n<p>\u6ce8\u610frelease\u51fd\u6570\u662f\u8ba9\u6307\u9488\u548c\u6307\u9488\u6307\u5411\u7684\u5bf9\u8c61\u8131\u79bb\u5173\u7cfb\uff0c\u5e76\u6ca1\u9500\u6bc1\u3002\u8981\u60f3\u9500\u6bc1\uff0c\u8c03\u7528reset\u4e00\u4e2a\u7a7a\u5bf9\u8c61\u3002<\/p>\n<h1>\u4e09\u3001shared_ptr<\/h1>\n<p>\u4ece\u540d\u5b57share\u5c31\u53ef\u4ee5\u770b\u51fa\u4e86\u8d44\u6e90\u53ef\u4ee5\u88ab\u591a\u4e2a\u6307\u9488\u5171\u4eab\uff0c\u5b83\u4f7f\u7528\u8ba1\u6570\u673a\u5236\u6765\u8868\u660e\u8d44\u6e90\u88ab\u51e0\u4e2a\u6307\u9488\u5171\u4eab\u3002\u53ef\u4ee5\u901a\u8fc7\u6210\u5458\u51fd\u6570use_count()\u6765\u67e5\u770b\u8d44\u6e90\u7684\u6240\u6709\u8005\u4e2a\u6570\u3002\u9664\u4e86\u53ef\u4ee5\u901a\u8fc7new\u6765\u6784\u9020\uff0c\u8fd8\u53ef\u4ee5\u901a\u8fc7\u4f20\u5165auto_ptr, unique_ptr,weak_ptr\u6765\u6784\u9020\u3002\u5f53\u6211\u4eec\u8c03\u7528release()\u65f6\uff0c\u5f53\u524d\u6307\u9488\u4f1a\u91ca\u653e\u8d44\u6e90\u6240\u6709\u6743\uff0c\u8ba1\u6570\u51cf\u4e00\u3002\u5f53\u8ba1\u6570\u7b49\u4e8e0\u65f6\uff0c\u8d44\u6e90\uff08\u6307\u5411\u7684\u5bf9\u8c61\uff09\u4f1a\u88ab\u91ca\u653e\u3002\u6b64\u5904\u8c03\u52a8reset\u4e0d\u80fd\u9500\u6bc1\u5bf9\u8c61\uff0c\u53ea\u6709\u5f53\u8ba1\u6570\u4e3a0\u65f6\u5019\u624d\u53ef\u4ee5\u3002<\/p>\n<p><span style=\"color: #ff0000;\">\u591a\u7ebf\u7a0b\u8c03\u7528\u5b83\u6307\u5411\u7684\u5bf9\u8c61\u7684\u65f6\u5019\uff0c\u4e00\u5b9a\u8981\u52a0\u9501\u3002<\/span><\/p>\n<pre class=\"pure-highlightjs\"><code class=\"\">\/*\r\n * main\r\n *\/\r\nint main(int argc, char* argv[]){\r\n    \/\/ shared_ptr\r\n    LOG(INFO) &lt;&lt; \"shared_ptr:\" &lt;&lt; std::endl;\r\n    std::shared_ptr&lt;String&gt; strAutoNull;\r\n    std::cout &lt;&lt; \"strAutoNull.use_count() = \" &lt;&lt; strAutoNull.use_count() &lt;&lt; std::endl;\r\n    std::shared_ptr&lt;String&gt; strAuto(new String(\"shared_ptr A\"));\r\n    \/\/std::shared_ptr&lt;String&gt; strAuto = std::shared_ptr&lt;String&gt;(new String(\"shared_ptr A\"));   \/\/shared_ptr\u4e0d\u7528\u663e\u5f0f\u5220\u9664\r\n    \/\/std::shared_ptr&lt;String&gt; strAuto = new_string_autoptr();\r\n    std::shared_ptr&lt;String&gt; strAuto2(strAuto);\r\n    std::shared_ptr&lt;String&gt; strAuto3 = strAuto;\r\n    strAuto = new_string_autoptr();\r\n    std::cout &lt;&lt; \"strAuto.use_count() = \" &lt;&lt; strAuto.use_count() &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"strAuto2.use_count() = \" &lt;&lt; strAuto2.use_count() &lt;&lt; std::endl;\r\n    strAuto.reset();    \/\/strAuto.reset()\u540e\u5f15\u7528\u8ba1\u6570\u4e3a0\uff0c\u89e6\u53d1\u81ea\u52a8\u9500\u6bc1\r\n    strAuto3.reset();   \/\/strAuto2\u5f15\u7528\u8ba1\u6570-1\uff0c\u4f46\u4ecd&gt;0\r\n    std::cout &lt;&lt; \"strAuto.use_count() = \" &lt;&lt; strAuto.use_count() &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"strAuto2.use_count() = \" &lt;&lt; strAuto2.use_count() &lt;&lt; std::endl;\r\n\r\n    String *pp = new String(\"pp\");   \/\/\u667a\u80fd\u6307\u9488\u8ba1\u6570-1\uff0c\u5e76\u5c06\u6307\u9488\u8f6c\u79fb\u7ed9p\uff08p\u666e\u901a\u6307\u9488\u5fc5\u987b\u901a\u8fc7delete\u6216\u6258\u7ba1\u7ed9\u667a\u80fd\u6307\u9488\u91ca\u653e\uff09\r\n    std::unique_ptr&lt;String&gt; pa2(pp); \r\n    \/\/std::unique_ptr&lt;String&gt; pa3(pp);    \/\/ERROR! \u540c\u4e00\u666e\u901a\u6307\u9488\u4e0d\u80fd\u540c\u65f6\u4e3a\u591a\u4e2a\u667a\u80fd\u6307\u9488\u8d4b\u503c\uff0c\u4f1a\u5bfc\u81f4\u6790\u6784\u5f02\u5e38\r\n\r\n    \/\/std::shared_ptr&lt;String&gt; pssl(new String[2]);    \/\/\u6570\u7ec4\u667a\u80fd\u6307\u9488\u4e0d\u80fd\u81ea\u52a8\u9500\u6bc1\r\n    std::shared_ptr&lt;String&gt; pssl(new String[2], std::default_delete&lt;String[]&gt;()); \/\/\u6570\u7ec4\u667a\u80fd\u6307\u9488\u9700\u8981\u6dfb\u52a0\u4e00\u4e2a\u5220\u9664\u5668\uff0c\u8fd9\u91cc\u4f7f\u7528default_delete&lt;T&gt; \u6a21\u677f\u7c7b\r\n    \/\/std::shared_ptr&lt;String&gt; pssl(new String[2], [](String* p) {delete[]p; }); \/\/\u6570\u7ec4\u667a\u80fd\u6307\u9488\u9700\u8981\u6dfb\u52a0\u4e00\u4e2a\u5220\u9664\u5668\uff0c\u8fd9\u91cc\u4f7f\u7528lambd\u8868\u8fbe\u5f0f\r\n    std::cout &lt;&lt; \"-------main end\" &lt;&lt; std::endl;\r\n    return 0;\r\n}\r\n\r\n\/\/\u8fd0\u884c\u7ed3\u679c\uff1a\r\nI1229 19:56:33.937842 321351104 main.cc:427] shared_ptr:\r\nstrAutoNull.use_count() = 0\r\nString(char* s) initialize: shared_ptr A\r\nString(char* s) initialize: shared_ptr\r\nstrAuto.use_count() = 1\r\nstrAuto2.use_count() = 2\r\n~String() destroy: shared_ptr\r\nstrAuto.use_count() = 0\r\nstrAuto2.use_count() = 1\r\nString(char* s) initialize: pp\r\nString() initialize: 0\r\nString() initialize: 0\r\n-------main end\r\n~String() destroy: 0\r\n~String() destroy: 0\r\n~String() destroy: pp\r\n~String() destroy: shared_ptr A\r\n<\/code><\/pre>\n<h1>\u56db\u3001week_ptr<\/h1>\n<p>weak_ptr\u53ef\u4ee5\u7528\u6765\u89e3\u51b3shared_ptr\u76f8\u4e92\u5f15\u7528\u65f6\u7684\u6b7b\u9501\u95ee\u9898,\u5982\u679c\u4e24\u4e2ashared_ptr\u76f8\u4e92\u5f15\u7528,\u90a3\u4e48\u8fd9\u4e24\u4e2a\u6307\u9488\u7684\u5f15\u7528\u8ba1\u6570\u6c38\u8fdc\u4e0d\u53ef\u80fd\u4e0b\u964d\u4e3a0,\u8d44\u6e90\u6c38\u8fdc\u4e0d\u4f1a\u91ca\u653e\u3002\u5b83\u662f\u5bf9\u5bf9\u8c61\u7684\u4e00\u79cd\u5f31\u5f15\u7528\uff0c\u4e0d\u4f1a\u589e\u52a0\u5bf9\u8c61\u7684\u5f15\u7528\u8ba1\u6570\uff0c\u548cshared_ptr\u4e4b\u95f4\u53ef\u4ee5\u76f8\u4e92\u8f6c\u5316\uff0cshared_ptr\u53ef\u4ee5\u76f4\u63a5\u8d4b\u503c\u7ed9\u5b83\uff0c\u5b83\u53ef\u4ee5\u901a\u8fc7\u8c03\u7528lock\u51fd\u6570\u6765\u83b7\u5f97shared_ptr\u3002weak_ptr\u4e5f\u53ef\u4ee5\u7528\u4e8e\u591a\u7ebf\u7a0b\u60f3\u4f7f\u7528\u5bf9\u8c61\uff0c\u4f46\u662f\u5e76\u4e0d\u7ba1\u7406\u5bf9\u8c61\u7684\u573a\u666f\u3002<\/p>\n<p>weak_ptr\u6ca1\u6709\u91cd\u8f7d * \u548c -&gt; \uff0c\u6240\u4ee5\u5e76\u4e0d\u80fd\u76f4\u63a5\u4f7f\u7528\u8d44\u6e90\u3002\u4f46\u53ef\u4ee5\u4f7f\u7528lock()\u83b7\u5f97\u4e00\u4e2a\u53ef\u7528\u7684shared_ptr\u5bf9\u8c61\uff0c<br \/>\n\u5982\u679c\u5bf9\u8c61\u5df2\u7ecf\u6b7b\u4e86\uff0clock()\u4f1a\u5931\u8d25\uff0c\u8fd4\u56de\u4e00\u4e2a\u7a7a\u7684shared_ptr\u3002<\/p>\n<pre class=\"pure-highlightjs\"><code class=\"\">int main(int argc, char* argv[]){\r\n    \/\/ weak_ptr\r\n    LOG(INFO) &lt;&lt; \"weak_ptr:\" &lt;&lt; std::endl;\r\n    std::shared_ptr&lt;int&gt; sp1(new int(10));\r\n    std::shared_ptr&lt;int&gt; sp2(sp1);\r\n    std::weak_ptr&lt;int&gt; wp(sp2); \/\/ weak_ptr\u6ca1\u6709\u91cd\u8f7d* \u548c -&gt; \uff0c\u65e0\u6cd5\u76f4\u63a5\u5f53\u6307\u9488\u7528\r\n    std::cout &lt;&lt; \"wp.use_count() = \" &lt;&lt; wp.use_count() &lt;&lt; std::endl;   \/\/\u8f93\u51fa\u548cwp\u540c\u6307\u5411\u7684shared_ptr\u7c7b\u578b\u6307\u9488\u7684\u6570\u91cf\r\n    sp2.reset();    \/\/\u91ca\u653e sp2\r\n    std::cout &lt;&lt; \"wp.use_count() = \" &lt;&lt; wp.use_count() &lt;&lt; std::endl;\r\n    std::cout &lt;&lt; \"*(wp.lock()) = \" &lt;&lt; *(wp.lock()) &lt;&lt; std::endl;    \/\/\u901a\u8fc7lock()\u51fd\u6570\uff0c\u8fd4\u56de\u4e00\u4e2a\u548cwp\u540c\u6307\u5411\u7684shared_ptr\u7c7b\u578b\u6307\u9488\uff0c\u5e76\u901a\u8fc7*\u83b7\u53d6\u5176\u5b58\u50a8\u7684\u6570\u636e\r\n    std::cout &lt;&lt; \"*(wp.lock()) = \" &lt;&lt; *(wp.lock()) &lt;&lt; std::endl;    \/\/\u4f7f\u7528lock\u83b7\u53d6\u7684\u539f\u56e0\r\n\r\n    std::cout &lt;&lt; \"-------main end\" &lt;&lt; std::endl;\r\n    return 0;\r\n}\r\n\r\n\/\/\u6267\u884c\u7ed3\u679c\r\nI1229 20:04:01.980633 200826304 main.cc:453] weak_ptr:\r\nwp.use_count() = 2\r\nwp.use_count() = 1\r\n*(wp.lock()) = 10\r\n*(wp.lock()) = 10<\/code><\/pre>\n<div><\/div>\n<div><\/div>\n<div class=\"cnblogs_code_toolbar\"><span style=\"color: #999999;\">\u53c2\u8003\uff1a<\/span><\/div>\n<div class=\"cnblogs_code_toolbar\"><span style=\"color: #999999;\">http:\/\/c.biancheng.net\/view\/7898.html<\/span><\/div>\n<div><span style=\"color: #999999;\">https:\/\/blog.csdn.net\/maosijunzi\/article\/details\/80772122<\/span><\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00\u3001\u6982\u8ff0 \u667a\u80fd\u6307\u9488\uff1a\u667a\u80fd\u6307\u9488\u662f\u4e00\u4e2a\u7c7b\uff0c\u7528\u6765\u5b58\u50a8\u6307\u9488\uff08\u6307\u5411\u52a8\u6001\u5206\u914d\u5bf9\u8c61\u4e5f\u5c31\u662f\u5806\u4e2d\u5bf9\u8c61\u7684\u7684\u6307\u9488\uff09\u3002 \u5728\u5b9e\u9645\u7684 C+ [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1027],"tags":[877,1039,1040,1041,1038],"_links":{"self":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/4478"}],"collection":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4478"}],"version-history":[{"count":0,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/4478\/revisions"}],"wp:attachment":[{"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4478"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4478"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yanjingang.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4478"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}