{"id":1371,"date":"2018-06-12T15:21:12","date_gmt":"2018-06-12T07:21:12","guid":{"rendered":"https:\/\/damogame.cn:15443\/wordpress\/?p=1371"},"modified":"2018-06-12T15:21:12","modified_gmt":"2018-06-12T07:21:12","slug":"%e8%af%a6%e8%a7%a3c11%e4%b8%ad%e7%a7%bb%e5%8a%a8%e8%af%ad%e4%b9%89stdmove%e5%92%8c%e5%ae%8c%e7%be%8e%e8%bd%ac%e5%8f%91stdforward","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/1371","title":{"rendered":"\u8be6\u89e3C++11\u4e2d\u79fb\u52a8\u8bed\u4e49(std::move)\u548c\u5b8c\u7f8e\u8f6c\u53d1(std::forward)"},"content":{"rendered":"
\n

\u8be6\u89e3C++11\u4e2d\u79fb\u52a8\u8bed\u4e49(std::move)\u548c\u5b8c\u7f8e\u8f6c\u53d1(std::forward)<\/h1>\n

Mar 26, 2016<\/p>\n<\/header>\n

\n
\n

\u524d\u8a00<\/h4>\n

\u6240\u6709\u7684\u624b\u6bb5\u90fd\u662f\u4e3a\u4e86\u89e3\u51b3\u5df2\u5b58\u5728\u7684\u95ee\u9898\u3002std::move\u548cstd::forward\u662fC++11\u4e2d\u7684\u7279\u6027\uff0c\u662f\u4e3a\u4e86\u89e3\u51b3C++98\/C++0x\u4e2d\u9057\u7559\u7684\u95ee\u9898\uff0c\u867d\u4ece\u7406\u89e3\u4e0a\u6765\u770b\u6bd4\u8f83\u590d\u6742\uff0c\u5374\u662f\u8f83\u597d\u7684\u89e3\u51b3\u624b\u6bb5\u3002<\/p>\n

\u5de6\u503c(lvalue)\u4e0e\u53f3\u503c(rvalue)<\/h4>\n

\u5de6\u503c\u4e0e\u53f3\u503c\u7684\u6982\u5ff5\u5176\u5b9e\u5728C++0x\u4e2d\u5c31\u6709\u4e86\u3002\u6982\u62ec\u7684\u8bb2\uff0c\u51e1\u662f\u80fd\u591f\u53d6\u5730\u5740\u7684\u53ef\u4ee5\u79f0\u4e4b\u4e3a\u5de6\u503c\uff0c\u53cd\u4e4b\u79f0\u4e4b\u4e3a\u53f3\u503c\uff0cC++\u4e2d\u5e76\u6ca1\u6709\u5bf9\u5de6\u503c\u548c\u53f3\u503c\u7ed9\u51fa\u660e\u786e\u7684\u5b9a\u4e49\uff0c\u4ece\u5176\u89e3\u51b3\u624b\u6bb5\u6765\u770b\u7c7b\u4f3c\u4e0a\u9762\u7684\u5b9a\u4e49\uff0c\u5f53\u7136\u6211\u4eec\u8fd8\u53ef\u4ee5\u5b9a\u4e49\u4e3a\uff1a\u6709\u540d\u5b57\u7684\u5bf9\u8c61\u4e3a\u5de6\u503c\uff0c\u6ca1\u6709\u540d\u5b57\u7684\u5bf9\u8c61\u4e3a\u53f3\u503c\u3002<\/p>\n

\n
class<\/span> A<\/span>\r\n{};\r\nA a; \/\/ a\u4e3a\u5de6\u503c\uff0c\u56e0\u4e3a\u5176\u6709\u660e\u786e\u540d\u5b57\uff0c\u4e14\u5bf9a\u8fdb\u884c &a \u662f\u5408\u6cd5\u7684\u3002<\/span>\r\n\r\nvoid<\/span> Test<\/span>(A a)<\/span>\r\n<\/span>{\r\n  __Test(a);\r\n}\r\nTest(A()); \/\/ A() \u4e3a\u53f3\u503c\uff0c\u56e0\u4e3aA()\u4ea7\u751f\u4e00\u4e2a\u4e34\u65f6\u5bf9\u8c61\uff0c\u4e34\u65f6\u5bf9\u8c61\u6ca1\u6709\u540d\u5b57\u4e14\u65e0\u6cd5\u8fdb\u884c &\u53d6\u5740\u64cd\u4f5c\u3002<\/span>\r\n\/*\r\n\u5bf9 __Test(a); \u800c\u8a00\uff0c\u8fd9\u91cc\u7684a\u4e3a\u5de6\u503c\uff0c\u56e0\u4e3a\u8fd9\u91cc\u7684a\u5bf9\u8c03\u7528\u65b9\u800c\u8a00\u662f\u5177\u540d\u7684\uff0c__Test\u5185\u90e8\u5bf9a\u4e5f\u662f\u53ef\u4ee5\u8fdb\u884c &\u53d6\u5740\u64cd\u4f5c\u7684\u3002\r\n\u4f46\u8fd9\u4e2aa\u5728\u8c03\u7528\u5b8c\u6bd5\u540e\u5f88\u5feb\u88ab\u9500\u6bc1\uff0c\u6bd5\u7adf\u5b83\u53ea\u662f\u4e00\u4e2a\u4e34\u65f6\u53d8\u91cf\u3002\r\n*\/<\/span>\r\n<\/code><\/pre>\n<\/div>\n
\u6240\u4ee5\u4ece\u4e0a\u8ff0\u7684\u4f2a\u4ee3\u7801\u4e2d\u8fd8\u53ef\u4ee5\u77e5\u9053\uff1a\u56e0\u4e3a\u51fd\u6570\u5185\u7684\u5d4c\u5957\u8c03\u7528\uff0c\u4e0a\u4e00\u5c42\u7684\u53f3\u503c\u662f\u53ef\u4ee5\u201c\u53d8\u6210\u201d\u5de6\u503c\u4ee5\u5b8c\u6210\u4e0b\u5c42\u8c03\u7528\uff0c\u610f\u5373\uff1a\u53ef\u4ee5\u63a5\u53d7\u53f3\u503c\u7684\u53f3\u503c\u5f15\u7528\u672c\u8eab\u5374\u662f\u4e2a\u5de6\u503c\u3002\uff08\u8fd9\u91cc\u4e3a\u4e86\u907f\u514d\u8bef\u5bfc\uff0c\u4f2a\u4ee3\u7801\u4e2d\u6ca1\u6709\u91c7\u7528 void Test(A &a) \u7684\u5f62\u5f0f\uff0c\u4e0d\u8fc7\u4e0b\u9762\u4f1a\u8bb2\u5230\u3002\uff09<\/p>\n
\u79fb\u52a8\u8bed\u4e49(std::move)<\/h4>\n
\u6709\u8fd9\u6837\u4e00\u6bb5\u4ee3\u7801\uff1a<\/p>\n
\n
class<\/span> A\r\n{\r\npublic<\/span>:\r\n  A() :array<\/span>(new<\/span> int<\/span>[3<\/span>]{1<\/span>, 2<\/span>, 3<\/span>})\r\n  {\r\n  }\r\n  ~A()\r\n  {\r\n    if<\/span>(nullptr<\/span> != a)\r\n    {\r\n      delete<\/span> [] a;\r\n    }\r\n  }\r\n  A(const<\/span> A& a)\r\n  {\r\n    std::cout<\/span> << \"Copy Construct\"<\/span> << endl;\r\n  }\r\n  private<\/span>:\r\n    int<\/span> *array<\/span>{nullptr<\/span>};\r\n  };\r\n  \r\n  int<\/span> main<\/span>()<\/span>\r\n  <\/span>{\r\n    A a1;\r\n    A a2<\/span>(a1)<\/span><\/span>;\r\n    return<\/span> 0<\/span>;\r\n  }\r\n\r\n\/*******************\r\n\u8f93\u51fa\uff1a\r\nCopy Construct\r\n*******************\/<\/span>\r\n<\/code><\/pre>\n<\/div>\n
\u4e0a\u9762\u7684\u4ee3\u7801\u548b\u770b\u4e0a\u53bb\u6ca1\u4ec0\u4e48\u95ee\u9898\uff0c\u4f46\u8fd9\u4ee3\u7801\u8fd8\u6709\u4f18\u5316\u7a7a\u95f4\uff1a\u5982\u679c\u5b9e\u9645\u4e0aarray\u6240\u6307\u7684\u662f\u4e00\u4e2a\u975e\u5e38\u5927\u7684\u6570\u7ec4\uff0c\u90a3\u4e48\u8fd9\u79cd\u62f7\u8d1d\u6784\u9020\u548c\u9500\u6bc1\u7684\u82b1\u9500\u662f\u975e\u5e38\u5927\u7684\uff0c\u5728\u67d0\u4e9b\u5e94\u7528\u573a\u666f\u4e0b\u751a\u81f3\u65e0\u6cd5\u63a5\u53d7\u8fd9\u79cd\u5927size\u5bf9\u8c61\u7684\u62f7\u8d1d\u3002\u6211\u4eec\u6709\u4e00\u4e2a\u7406\u60f3\uff1a\u4efb\u4f55\u5927size\u7684\u5bf9\u8c61\uff0c\u80fd\u5426\u5728\u5176\u8fdb\u884c\u62f7\u8d1d\uff08\u62f7\u8d1d\u6784\u9020\u3001\u62f7\u8d1d\u8d4b\u503c\u64cd\u4f5c\uff09\u65f6\u4ec5\u4ec5\u53ea\u62f7\u8d1d\u5176class\u5185\u90e8\u7684\u5927size\u5bf9\u8c61\uff0c\u8fd9\u6837\u5c31\u907f\u514d\u4e86\u5927size\u5bf9\u8c61\u7684\u6784\u9020\u548c\u9500\u6bc1\u7684\u989d\u5916\u82b1\u9500\uff0c\u7b54\u6848\u662f\u80af\u5b9a\u7684\u3002<\/p>\n
\n
class<\/span> A\r\n{\r\npublic<\/span>:\r\n  A() :array<\/span>(new<\/span> int<\/span>[3<\/span>]{1<\/span>, 2<\/span>, 3<\/span>})\r\n  {\r\n  }\r\n  ~A()\r\n  {\r\n    if<\/span>(nullptr<\/span> != a)\r\n    {\r\n      delete<\/span> [] a;\r\n    }\r\n  }\r\n  A(A &&a)\r\n  {\r\n    array<\/span> = a.array<\/span>;\r\n    a.array<\/span> = nullptr<\/span>;\r\n    std::cout<\/span> << \"Memory Copy Construct\"<\/span> << endl;\r\n  }\r\npublic<\/span>:\r\n  int<\/span> *array<\/span>{nullptr<\/span>};\r\n};\r\n\r\nA GetTempObj<\/span>()<\/span>\r\n<\/span>{\r\n  A a;\r\n  std::cout<\/span> << a.array<\/span> << endl;\r\n  return a;\r\n}\r\n\r\nint<\/span> main()\r\n{\r\n  A a(GetTempObj());  \/\/ \u5b9e\u9645\u4e0a\u8fd9\u6bb5\u4ee3\u7801\u5e76\u4e0d\u6807\u51c6\uff0c\u4f9d\u6258\u7f16\u8bd1\u5668\u5b9e\u73b0\r\n  std<\/span>::cout<\/span> << a.array<\/span> << endl;\r\n  return 0;\r\n}\r\n\r\n\/****************************\r\n\u8f93\u51fa\uff1a\r\n00BEF138\r\nMemory Copy Construct\r\n00BEF138\r\n****************************\/\r\n<\/span><\/code><\/pre>\n<\/div>\n
\u4e0a\u9762\u7684\u4ee3\u7801\u4e2d\u6211\u4eec\u4f3c\u4e4e\u5b9e\u73b0\u4e86\u4ec5\u4ec5\u53ea\u62f7\u8d1d\u4e86A\u4e2darray\u6240\u6307\u7684\u5185\u5b58\u3002GetTempObj()\u8fd4\u56de\u4e86\u4e00\u4e2a\u4e34\u65f6\u5bf9\u8c61\uff08\u6ce8\uff1a\u5728VS2012\u4ee5\u4e0a\u7f16\u8bd1\u5668\u4f1a\u8fdb\u884cRVO\u4f18\u5316\uff0cRVO\u4f18\u5316\u6682\u65f6\u4e0d\u5728\u672c\u6587\u8ba8\u8bba\u4e4b\u5217\uff09\uff0c\u8fd9\u4e2a\u4e34\u65f6\u5bf9\u8c61\u7528\u6765\u521d\u59cb\u5316a\u5bf9\u8c61\u3002\u4e0a\u9762\u7684\u4ee3\u7801\u6253\u5370\u4e86array\u7684\u5730\u5740\uff0c\u4ece\u7ed3\u679c\u4e0a\u770b\uff0c\u6211\u4eec\u5b9e\u73b0\u4e86\u4e24\u4e2a\u5bf9\u8c61\u4e4b\u95f4\u5728\u62f7\u8d1d\u6784\u9020\u51fa\u73b0\u65f6\u81f3\u53ea\u62f7\u8d1d\u5176\u5927size\u5185\u5b58\u3002\u4e0a\u9762\u7684\u4ee3\u7801\u9002\u7528\u4e8e\u4e00\u4e2a\u5de6\u503c\u4e0e\u4e00\u4e2a\u53f3\u503c\u4e4b\u95f4\u7684\u62f7\u8d1d\u6784\u9020\uff0c\u6211\u4eec\u79f0\u4e4b\u4e3a\u79fb\u52a8\u62f7\u8d1d\u6784\u9020\u3002\u7ec6\u601d\u4e00\u4e0b\uff0c\u6211\u4eec\u8fd8\u60f3\u8981\uff1a<\/p>\n
\n
A a1;\r\nA a2<\/span>(a1)<\/span><\/span>; \/\/ error\uff1a 'A::A(const A &)': attempting to reference a deleted function<\/span>\r\n<\/code><\/pre>\n<\/div>\n
\u4e0a\u9762\u7684\u4ee3\u7801\u65e0\u6cd5\u901a\u8fc7\u7f16\u8bd1\uff0c\u9700\u8981\u6211\u4eec\u663e\u793a\u7684\u6307\u660e\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff08\u56e0\u4e3a\u6211\u4eec\u5b9e\u73b0\u4e86\u79fb\u52a8\u62f7\u8d1d\u6784\u9020\uff0c\u7f16\u8bd1\u5668\u8ba4\u4e3a\u5b83\u4e0d\u9700\u8981\u81ea\u52a8\u751f\u6210\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff09\u624d\u80fd\u901a\u8fc7\u3002\u867d\u8bf4\u5982\u6b64\uff0c\u5b9e\u9645\u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u4e0d\u53ef\u80fd\u603b\u662f\u9760GetTempObj()\u8fd4\u56de\u4e34\u65f6\u5bf9\u8c61\uff08\u53f3\u503c\uff09\u4ee5\u5b9e\u73b0\u79fb\u52a8\u62f7\u8d1d\u6784\u9020\uff0c\u9700\u8981\u4e00\u79cd\u7279\u522b\u7684\u89e3\u51b3\u624b\u6bb5\u3002<\/p>\n
\u5728\u8fd9\u79cd\u573a\u666f\u4e0b\uff0cstd::move\u5e94\u8fd0\u800c\u751f\u3002std::move\u5728\u540d\u5b57\u4e0a\u6709\u4e00\u5b9a\u7684\u8bef\u5bfc\u6027\uff0c\u4f46\u5b83\u4e0d\u79fb\u52a8\u4efb\u4f55\u4e1c\u897f<\/strong>\u3002<\/p>\n
\u65b0\u7684\u6807\u51c6\u8ba4\u4e3a\uff1a\u79fb\u52a8\u6784\u9020\u51fd\u6570\u548c\u79fb\u52a8\u62f7\u8d1d\u51fd\u6570\u5e94\u5bf9\u5de6\u503c\u548c\u53f3\u503c\u6709\u4e0d\u540c\u7684\u5904\u7406\uff0c\u800cstd::move\u5c31\u662f\u5176\u7edf\u4e00\u7684\u89e3\u51b3\u624b\u6bb5\u3002std::move\u53ef\u4ee5\u5c06\u4e00\u4e2a\u5de6\u503c\u8f6c\u5316\u4e3a\u53f3\u503c\u5f15\u7528\u4ee5\u5b9e\u73b0\u79fb\u52a8\u62f7\u8d1d\uff08\u4e0b\u9762\u4f1a\u8bf4move\u5982\u4f55\u8f6c\u6362\u7684\uff09\uff0c\u56e0\u6b64\u5bf9\u4e8e\u4e24\u4e2a\u5de6\u503c\u4e4b\u95f4\u7684\u62f7\u8d1d\uff0c\u6211\u4eec\u53ef\u4ee5\u8fd9\u6837\uff1a<\/p>\n
\n
A a1;\r\nA a2<\/span>(std<\/span>::move(a1)<\/span>)<\/span>; \/\/ correctly<\/span>\r\n<\/code><\/pre>\n<\/div>\n
\u6240\u4ee5\uff0c\u5b9e\u73b0\u4e00\u4e2a\u5177\u6709\u79fb\u52a8\u62f7\u8d1d\u6784\u9020\u548c\u79fb\u52a8\u62f7\u8d1d\u51fd\u6570\u7684\u7c7b\uff1a<\/p>\n
\n
class<\/span> A\r\n{\r\npublic<\/span>:\r\n  A() :array<\/span>(new<\/span> int<\/span>[3<\/span>]{1<\/span>, 2<\/span>, 3<\/span>})\r\n  {\r\n  }\r\n\r\n  ~A()\r\n  {\r\n    if<\/span>(nullptr<\/span> != a)\r\n    {\r\n      delete<\/span> [] a;\r\n    }\r\n  }\r\n\r\n  A(A &&a)\r\n  {\r\n  }\r\n\r\n  A& operator<\/span> = (A &&rhs)\r\n  {\r\n    return<\/span> *this<\/span>;\r\n  }\r\n};\r\n<\/code><\/pre>\n<\/div>\n
\u4e8b\u5b9e\u4e0a\uff0c\u4e3a\u4e86\u4fdd\u8bc1\u79fb\u52a8\u8bed\u4e49\u7684\u4f20\u9012\uff0c\u6211\u4eec\u5728\u7f16\u5199\u79fb\u52a8\u6784\u9020\u51fd\u6570\u7684\u65f6\u5019\uff0c\u5e94\u8be5\u603b\u662f\u8bb0\u5f97\u4f7f\u7528std::move\u8f6c\u6362\u62e5\u6709\u5f62\u5982\u5806\u5185\u5b58\u3001\u6587\u4ef6\u53e5\u67c4\u7b49\u8d44\u6e90\u7684\u6210\u5458\u4e3a\u53f3\u503c\uff0c\u8fd9\u6837\u4e00\u6765\uff0c\u5982\u679c\u6210\u5458\u652f\u6301\u79fb\u52a8\u6784\u9020\u7684\u8bdd\uff0c\u5c31\u53ef\u4ee5\u5b9e\u73b0\u5176\u79fb\u52a8\u8bed\u4e49\u3002\u800c\u5373\u4f7f\u6210\u5458\u6ca1\u6709\u79fb\u52a8\u6784\u9020\u51fd\u6570\uff0c\u90a3\u4e48\u63a5\u53d7\u5e38\u91cf\u5de6\u503c\u7684\u6784\u9020\u51fd\u6570\u7248\u672c\u4e5f\u4f1a\u8f7b\u677e\u5730\u5b9e\u73b0\u62f7\u8d1d\u6784\u9020\uff08\u6ca1\u6709\u79fb\u52a8\u51fd\u6570\u7684\u8bdd\uff0cstd::move\u4f1a\u9ed8\u8ba4\u8fdb\u884c\u62f7\u8d1d\u64cd\u4f5c\uff09\u800c\u4e0d\u4f1a\u5f15\u8d77\u5927\u7684\u95ee\u9898\u3002<\/p>\n
\u73b0\u5728\u6709\u8fd9\u6837\u7684\u4ee3\u7801\uff1a<\/p>\n
\n
A Get<\/span>()<\/span>\r\n<\/span>{\r\n  return<\/span> A();\r\n}\r\n\r\nA a<\/span>(A()<\/span>)<\/span>;\r\nA a1<\/span>(Get()<\/span>)<\/span>;\r\n<\/code><\/pre>\n<\/div>\n
\u4e8b\u5b9e\u4e0a\uff0ca\u548ca1\u90fd\u4e0d\u4f1a\u51fa\u53d1\u79fb\u52a8\u51fd\u6570\uff08\u79fb\u52a8\u6784\u9020\u548c\u79fb\u52a8\u62f7\u8d1d\uff09\uff0c\u56e0\u4e3aA()\u548cGet()\u8fd4\u56de\u7684\u4e34\u65f6\u5bf9\u8c61\uff0c\u662f\u4e00\u4e2a\u53f3\u503c\u3002\u90a3\u4e48\u80fd\u5426\u5bf9\u8fd9\u79cd\u4e34\u65f6\u5bf9\u8c61\u65bd\u52a0std::move\u4ee5\u5b9e\u73b0\u8c03\u7528\u79fb\u52a8\u51fd\u6570\u5462\uff1f\u8fd9\u91cc\u5c31\u6d89\u53ca\u5230\u4e86\u5de6\u503c\u5f15\u7528\u548c\u53f3\u503c\u5f15\u7528\u3002<\/p>\n
\u53f3\u503c\u5f15\u7528<\/h5>\n
\u5de6\u503c\u5f15\u7528\u4e0e\u53f3\u503c\u5f15\u7528\u5927\u53ef\u53c2\u7167\u5de6\u503c\u4e0e\u53f3\u503c\u3002\u6211\u4eec\u77e5\u9053\u53ef\u4ee5\u4f7f\u7528std::move\u5c06\u4e00\u4e2a\u5de6\u503c\u8f6c\u6362\u4e3a\u53f3\u503c\u5f15\u7528\u4ee5\u4fbf\u8c03\u7528\u79fb\u52a8\u51fd\u6570\u3002\u90a3\u4e48\u95ee\u9898\u6765\u4e86\uff0c\u53f3\u503c\u5f15\u7528\u53ef\u4ee5\u4f7f\u7528std::move\u5417\uff1f\u7b54\u6848\u662f\u80af\u5b9a\u7684\u3002\u5177\u4f53\u6765\u8bb2\uff0c\u5de6\u503c\u5f15\u7528\u548c\u53f3\u503c\u5f15\u7528\u662f\u53ef\u4ee5\u76f8\u4e92\u7ed1\u5b9a\u7684\uff0c\u4f46\u5b83\u4eec\u9075\u5faa\u89c4\u5219\uff1a<\/p>\n
    \n
  1. \u975econst\u5de6\u503c\u5f15\u7528\u53ea\u80fd\u7ed1\u5b9a\u5230\u975econst\u5de6\u503c\uff1b<\/li>\n
  2. const\u5de6\u503c\u5f15\u7528\u53ef\u7ed1\u5b9a\u5230const\u5de6\u503c\u3001\u975econst\u5de6\u503c\u3001const\u53f3\u503c\u3001\u975econst\u53f3\u503c\uff1b<\/li>\n
  3. \u975econst\u53f3\u503c\u5f15\u7528\u53ea\u80fd\u7ed1\u5b9a\u5230\u975econst\u53f3\u503c\uff0c\u4f46\u4e0d\u9002\u7528\u4e8e\u51fd\u6570\u6a21\u677f\u7684\u5f62\u53c2\uff1b<\/li>\n
  4. const\u53f3\u503c\u5f15\u7528\u53ef\u7ed1\u5b9a\u5230const\u53f3\u503c\u548c\u975econst\u53f3\u503c\uff0c\u5b83\u6ca1\u6709\u73b0\u5b9e\u610f\u4e49\uff08\u6bd5\u7adf\u53f3\u503c\u5f15\u7528\u7684\u521d\u8877\u5728\u4e8e\u79fb\u52a8\u8bed\u4e49\uff0c\u800c\u79fb\u52a8\u5c31\u610f\u5473\u7740\u4fee\u6539<\/strong>\uff09\uff1b<\/li>\n<\/ol>\n
    \u6211\u4eec\u60f3\u8ba9a\u548ca1\u5b9e\u73b0\u79fb\u52a8\u51fd\u6570\u7684\u8c03\u7528\uff0c\u4ece\u4e0a\u9762\u6765\u4e0a\u770b\uff0c\u6211\u4eec\u9700\u8981\u5c06A()\u548cGet()\u7684\u8fd4\u56de\u503c\u8f6c\u6362\u6210\u975econst\u53f3\u503c\u624d\u4f1a\u5b9e\u73b0\u79fb\u52a8\u51fd\u6570\u7684\u8c03\u7528\uff0c\u7b54\u6848\u5c31\u662f\uff1astd::move\u3002<\/p>\n
    \n
    template<\/span><typename<\/span> T>  \r\ninline<\/span> typename<\/span> std::remove_reference<T>::type&&  \r\nmove(T&& t)  \r\n{ \r\n  return<\/span> static_cast<\/span><typename<\/span> std::remove_reference<T>::type&&>(t); \r\n}  \r\n<\/code><\/pre>\n<\/div>\n
    \u6839\u636e\u6a21\u677f\u53c2\u6570\u63a8\u5bfc\u89c4\u5219\uff0c\u5f53\u4f20\u5165\u53c2\u6570\u662f\u4e00\u4e2a\u5de6\u503c\u7684\u65f6\u5019\uff0cT\u4f1a\u88ab\u63a8\u5bfc\u4e3aT&\uff0c\u4e8e\u662fT& + T&&\u63a8\u5bfc\u4e3aT&\uff0c\u5b9e\u9645\u4e0a\u4e5f\u5c31\u662fmove(&)\uff0c\u5f53\u4f20\u5165\u53c2\u6570\u662f\u4e00\u4e2a\u53f3\u503cT&&\u7684\u65f6\u5019\uff0c\u6839\u636e T&& + T&&\u63a8\u5bfc\u4e3aT&&\uff0c\u6240\u4ee5\u65e0\u8bba\u5982\u4f55\uff0cmove\u6700\u7ec8\u4e00\u5b9a\u662f\u8fd4\u56de\u4e86T&&\u3002\u5bf9\u4e8e\u7c7b\u578b\u63a8\u5bfc\uff1a<\/p>\n
    \u5f53\u51fd\u6570\u6a21\u677f\u7684\u6a21\u677f\u53c2\u6570\u4e3aT\u800c\u51fd\u6570\u5f62\u53c2\u4e3aT&&\uff08\u53f3\u503c\u5f15\u7528\uff09\u65f6\u9002\u7528\u672c\u89c4\u5219\u3002\u82e5\u5b9e\u53c2\u4e3a\u5de6\u503c A& \uff0c\u5219\u6a21\u677f\u53c2\u6570 T \u5e94\u63a8\u5bfc\u4e3a\u5f15\u7528\u7c7b\u578b A& \u3002\uff08\u6839\u636e\u5f15\u7528 \u6298\u53e0\u89c4\u5219\uff0c A& + && => A&\uff0c \u800cT&& <=> A&\uff0c\u6545T <=> A& \uff09\u82e5\u5b9e\u53c2\u4e3a\u53f3\u503c A&& \uff0c\u5219\u6a21\u677f\u53c2\u6570 T \u5e94\u63a8\u5bfc\u4e3a\u975e\u5f15\u7528\u7c7b\u578b A \u3002\uff08\u6839\u636e\u5f15\u7528\u6298\u53e0\u89c4\u5219\uff0c A\u6216A&& + && => A&&\uff0c \u800cT&& <=> A&&\uff0c\u6545T <=> A\u6216A&&\uff0c\u8fd9\u91cc\u5f3a\u5236\u89c4\u5b9aT <=> A\uff09\u3002<\/p><\/blockquote>\n
    \u6240\u4ee5\u6211\u4eec\u7684\u4ee3\u7801\u9700\u8981\u8fdb\u884c\u4fee\u6539\u4ee5\u8c03\u7528A\u7684\u79fb\u52a8\u6784\u9020\u51fd\u6570\uff0c\u79fb\u52a8\u62f7\u8d1d\u51fd\u6570\u4e5f\u540c\u7406\u5982\u6b64\uff1a<\/p>\n
    \n
    A a<\/span>(std<\/span>::move(A()<\/span>))<\/span>;\r\nA a1<\/span>(std<\/span>::move(Get()<\/span>))<\/span>;\r\n<\/code><\/pre>\n<\/div>\n
    \u8fd8\u8bb0\u5f97C++98\/0x\u4e2d\u7684auto_ptr\u5417\uff1fauto_ptr\u5728\u201d\u62f7\u8d1d\u201d\u7684\u65f6\u5019\u5176\u5b9e\u5e76\u975e\u4e25\u683c\u610f\u4e49\u4e0a\u7684\u62f7\u8d1d\u3002\u201d\u62f7\u8d1d\u201d\u662f\u8981\u4fdd\u7559\u6e90\u5bf9\u8c61\u4e0d\u53d8\uff0c\u5e76\u57fa\u4e8e\u5b83\u590d\u5236\u51fa\u4e00\u4e2a\u65b0\u7684\u5bf9\u8c61\u51fa\u6765\u3002\u4f46auto_ptr\u7684\u201d\u62f7\u8d1d\u201d\u5374\u4f1a\u5c06\u6e90\u5bf9\u8c61\u201d\u638f\u7a7a\u201d\uff0c\u53ea\u7559\u4e00\u4e2a\u7a7a\u58f3\uff0c\u5b9e\u9645\u4e0a\u662f\u4e00\u6b21\u8d44\u6e90\u6240\u6709\u6743\u7684\u8f6c\u79fb\uff0c\u4f46auto_ptr\u7684\u5371\u9669\u4e4b\u5904\u5728\u4e8e\u770b\u4e0a\u53bb\u5e94\u8be5\u662f\u590d\u5236\uff0c\u5b9e\u9645\u4e0a\u786e\u5b9e\u8f6c\u79fb\u3002auto_ptr\u8c03\u7528\u88ab\u8f6c\u79fb\u8fc7\u7684\u7684\u6210\u5458\u51fd\u6570\u5c06\u4f1a\u5bfc\u81f4\u4e0d\u53ef\u9884\u77e5\u7684\u540e\u679c, C++11\u4e2d\u88abunique_ptr\u66ff\u6362\uff0c\u800cunique_ptr\u5c31\u662f\u7528move\u8bed\u4e49\u5b9e\u73b0\u7684\u3002<\/p>\n
    std::move\u7684\u5173\u952e\u5b57\uff1a\u6548\u7387\u4f18\u5316<\/h5>\n
    \u6211\u4eec\u9996\u5148\u662f\u8981\u89e3\u51b3\u4e00\u4e9b\u95ee\u9898\u7684\u3002std::move\u7684\u51fa\u73b0\u5c31\u662f\u89e3\u51b3\u5728\u6548\u7387\u4e0a\u7684\u95ee\u9898\uff0c\u51cf\u5c11\u4e0d\u5fc5\u8981\u7684\u62f7\u8d1d\u3002\u5982\u679c\u5b58\u5728\u8fd9\u6837\u4e00\u4e2a\u79fb\u52a8\u6784\u9020\u51fd\u6570\u7684\u8bdd\uff0c\u6240\u6709\u6e90\u5bf9\u8c61\u4e3a\u4e34\u65f6\u5bf9\u8c61\u7684\u62f7\u8d1d\u6784\u9020\u884c\u4e3a\u90fd\u53ef\u4ee5\u7b80\u5316\u4e3a\u79fb\u52a8\u5f0f(move)\u6784\u9020\u3002\u5bf9\u4e8e\u666e\u901a\u7684string\u7c7b\u578b\u800c\u8a00\uff0cstd::move\u548ccopy construction\u4e4b\u95f4\u7684\u6548\u7387\u5dee\u662f\u8282\u7701\u4e86\u4e00\u6b21O(n)\u7684\u5206\u914d\u64cd\u4f5c\uff0c\u4e00\u6b21O(n)\u7684\u62f7\u8d1d\u64cd\u4f5c\uff0c\u4e00\u6b21O(1)\u7684\u6790\u6784\u64cd\u4f5c\uff08\u88ab\u62f7\u8d1d\u7684\u90a3\u4e2a\u4e34\u65f6\u5bf9\u8c61\u7684\u6790\u6784\uff09\u3002\u8fd9\u91cc\u7684\u6548\u7387\u63d0\u5347\u662f\u663e\u800c\u6613\u89c1\u4e14\u663e\u8457\u7684\u3002<\/p>\n
    \u5b8c\u7f8e\u8f6c\u53d1(std::forward)<\/h4>\n
    \u7a0b\u5e8f\u5458\u5728\u4e0d\u5199\u9ad8\u5ea6\u6cdb\u578b\u4ee3\u7801\u7684\u65f6\u5019\uff0c\u5b8c\u7f8e\u8f6c\u53d1\u7684\u597d\u5904\u53ef\u80fd\u8fd8\u4f53\u4f1a\u4e0d\u5230\uff0c\u5728C++98\/0x\u65f6\u4ee3\uff0c\u5f53\u6211\u4eec\u9700\u8981\u5199\u6cdb\u578b\u4ee3\u7801\u7684\u65f6\u5019\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u51fd\u6570\u8c03\u7528\u7684\u4e00\u4e9b\u95ee\u9898\u3002<\/p>\n
    \n
    void<\/span> __Test(int<\/span> &t)\r\n{\r\n}\r\n\r\ntemplate<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(const<\/span> T &t)<\/span>\r\n<\/span>{\r\n  \/\/ do other things... <\/span>\r\n  __Test(t);\r\n}\r\n\r\nint<\/span> i = 0<\/span>;\r\nTest(i);\r\n<\/code><\/pre>\n<\/div>\n
    \u4e0a\u8ff0\u7684\u4ee3\u7801\u5c06\u4f1a\u65e0\u6cd5\u901a\u8fc7\u7f16\u8bd1\uff0c\u7a76\u5176\u539f\u56e0\uff0ct\u5728\u8fdb\u5165Test\u4e4b\u540e\u4e3aconst T&\uff0c\u800c\u8c03\u7528__Test\u4e4b\u540e\u662fT&\uff0c\u6a21\u677f\u65e0\u6cd5\u4ececonst T&\u63a8\u5bfc\u4e3aT&\u3002\u9488\u5bf9\u8fd9\u4e2a\u95ee\u9898\uff0c\u6211\u4eec\u6709\u4e24\u79cd\u65b9\u6cd5\u89e3\u51b3\uff1a<\/p>\n
    \n
    template<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(const<\/span> T& t)<\/span>\r\n<\/span>{\r\n  \/\/ do other things...<\/span>\r\n  __Test(const_cast<\/span><T&>(t));\r\n}\r\n<\/code><\/pre>\n<\/div>\n
    \u7ecf\u8fc7\u4fee\u6539\u540e\uff0cTest\u53ef\u4ee5\u7f16\u8bd1\u901a\u8fc7\u3002\u6211\u4eec\u901a\u8fc7const_cast\u53bb\u6389\u4e86const\u5c5e\u6027\uff0c\u4ed4\u7ec6\u60f3\u60f3\uff0c\u7528const_cast\u5408\u9002\u5417\uff1f\u663e\u7136\u8fd9\u91cc\u7528const_cast\u7834\u574f\u4e86\u51fd\u6570\u7684\u5065\u58ee\u6027\u3002\u6709\u6ca1\u6709\u5176\u4ed6\u7684\u65b9\u6cd5\u89e3\u51b3\u5462\uff1f\u6211\u4eec\u7279\u5316\u6a21\u677f\u8868\u4ee5\u9002\u5f53\u7684\u7c7b\u578b\u6216\u91cd\u8f7d\u8c03\u7528\u51fd\u6570\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff1a<\/p>\n
    \n
    void<\/span> __Test(const<\/span> int<\/span> &t)\r\n{}\r\n\r\n\/\/ or<\/span>\r\nvoid<\/span> __Test(int<\/span> & t)\r\n{}\r\n\/\/ or<\/span>\r\ntemplate<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(T &t)<\/span>\r\n<\/span>{}\r\n\r\n\/\/ or<\/span>\r\ntemplate<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(T &t)<\/span>\r\n<\/span>{}\r\n<\/code><\/pre>\n<\/div>\n
    \u8fd9\u6837\u95ee\u9898\u987a\u5229\u89e3\u51b3\uff0c\u65e0\u8bba\u662f\u6211\u4eec\u8c03\u7528Test(i)\u8fd8\u662fTest(5)\u90fd\u53ef\u4ee5\u987a\u5229\u901a\u8fc7\u7f16\u8bd1\u3002<\/p>\n
    \u73b0\u5b9e\u4e16\u754c\u91cc\u7684\u4ee3\u7801\u4e0d\u4f1a\u8fd9\u4e48\u7b80\u5355\uff0c\u4e0a\u9762\u7684\u6d4b\u8bd5\u4ee3\u7801\u53ea\u6d89\u53ca\u5230\u4e86\u4e00\u4e2a\u53c2\u6570\uff0c\u5047\u5982\u67d0\u4e00\u6a21\u677f\u51fd\u6570\u6709\u4e24\u4e2a\u53c2\u6570\u9047\u5230\u8fd9\u79cd\u60c5\u51b5\u4e4b\u540e\u600e\u4e48\u529e\uff1fC++0x\/98\u4e0b\u6211\u4eec\u53ef\u80fd\u4f1a\u5199\u51fa\u8fd9\u6837\u7684\u4ee3\u7801\uff1a<\/p>\n
    \n
    template<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(T &t1, T &t2)<\/span>\r\n<\/span>{\r\n  __Test(t1, t2);\r\n}\r\ntemplate<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(const<\/span> T &t1, const<\/span> T &t2)<\/span>\r\n<\/span>{\r\n  __Test(t1, t2);\r\n}\r\ntemplate<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(const<\/span> T &t1, T &t2)<\/span>\r\n<\/span>{\r\n  __Test(t1, t2);\r\n}\r\ntemplate<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(T &t1, const<\/span> T &t2)<\/span>\r\n<\/span>{\r\n  __Test(t1, t2);\r\n}\r\n<\/code><\/pre>\n<\/div>\n
    \u5f53\u6211\u5199\u5b8c\u8fd9\u4e00\u6bb5\u793a\u4f8b\u4ee3\u7801\uff0c\u6211\u7684\u7b2c\u4e00\u611f\u89c9\u662f\uff1a\u8fd9\u7b80\u76f4\u5c31\u662f\u4e00\u6bb5\u6beb\u65e0\u6280\u672f\u542b\u91cf\u7684\u6d3b\uff0c\u7a0b\u5e8f\u5458\u4e07\u4e07\u4e0d\u80fd\u5c06\u65f6\u95f4\u6d6a\u8d39\u5728\u8fd9\u4e00\u6bb5\u4ee3\u7801\u4e0a\u9762\u3002\u5f53\u6211\u4eec\u6709\u4e24\u4e2a\u53c2\u6570\u7684\u6a21\u677f\u51fd\u6570\u4f1a\u67094\u4e2a\u7279\u5316.\u95ee\u9898\u4e0d\u5728\u8fd9\u91cc\uff0c\u56e0\u4e3a\u53c2\u6570\u7c7b\u578b\u4e0d\u540c\uff0cTest\u6700\u7ec8\u5c06\u53c2\u6570\u8f6c\u53d1\u5230__Test\u4e2d\u4e86\uff0c\u610f\u5473\u7740\u4ec0\u4e48\uff1f\u610f\u5473\u7740\u6211\u4eec\u8fd8\u8981\u4e3a__Test\u91cd\u8f7d\u4e0d\u540c\u53c2\u6570\u7c7b\u578b\u7684\u7248\u672c\u3002\u4e24\u4e2a\u53c2\u6570\u80fd\u91cd\u8f7d\u51fa4\u4e2a\uff0c\u5982\u679c\u6709\u4e09\u4e2a\u53c2\u6570\uff0c\u56db\u4e2a\u53c2\u6570\u751a\u81f3\u4e94\u4e2a\u53c2\u6570\u7684\u65f6\u5019\uff0c__Test\u7a76\u7adf\u9700\u8981\u591a\u5c11\u4e2a\u91cd\u8f7d\u51fd\u6570\u624d\u80fd\u6ee1\u8db3\uff1f\u8fd9\u6837\u5c31\u662f\u4e3a\u4ec0\u4e48VC9\u7684std::bind\u91cc\u97625\u4e2a\u53c2\u6570\u5c31\u91cd\u8f7d\u4e8663\u4e2a\u51fd\u6570\uff0c\u591a\u4e48\u5e9e\u5927\u7684\u6570\u91cf\uff0c\u800c\u8fd9\u4e9b\u5168\u662f\u9760\u4eba\u529b\u5806\u79ef\u8d77\u6765\u7684\u3002<\/p>\n
    \u8981\u4e48\u5c06\u6a21\u677f\u51fd\u6570Test\u6570\u91cf\u51cf\u5c11\uff0c\u8981\u4e48\u5c06\u88ab\u8f6c\u53d1\u51fd\u6570__Test\u6570\u91cf\u51cf\u5c11\uff0c\u7a0b\u5e8f\u5458\u5e94\u8be5\u5c06\u5927\u8111\u548c\u624b\u7528\u5728\u9700\u8981\u7684\u5730\u65b9\u3002<\/p>\n
    \u73b0\u5728\u6211\u4eec\u6709\u4e86\u5de6\u503c\u548c\u53f3\u503c\u5f97\u6982\u5ff5\uff0c\u8fd9\u79cd\u95ee\u9898\u6709\u6bd4\u8f83\u597d\u7684\u89e3\u51b3\u624b\u6bb5\u3002<\/p>\n
    \n
    template<\/span><typename<\/span> T>\r\nstruct<\/span> RemoveReference\r\n{\r\n  typedef<\/span> T Type;\r\n};\r\n\r\ntemplate<\/span><typename<\/span> T>\r\nstruct<\/span> RemoveReference<T&>\r\n{\r\n  typedef<\/span> T Type;\r\n};\r\n\r\ntemplate<\/span><typename<\/span> T>\r\nstruct<\/span> RemoveReference<T&&>\r\n{\r\n  typedef<\/span> T Type;\r\n};\r\n\r\ntemplate<\/span><typename<\/span> T>\r\nT&& ForwardValue(typename<\/span> RemoveReference<T>::Type&& value)\r\n{\r\n  return<\/span> (T&&)value;\r\n}\r\n\r\ntemplate<\/span><typename<\/span> T>\r\nT&& ForwardValue(typename<\/span> RemoveReference<T>::Type& value)\r\n{\r\n  return<\/span> (T&&)value;\r\n}\r\n<\/code><\/pre>\n<\/div>\n
    \u6709\u4e86\u4e0a\u9762\u7684\u4ee3\u7801\u4e4b\u540e\uff08\u5b9e\u9645\u4e0a\u4e5f\u5c31\u662fstd::forward\u7684\u5927\u81f4\u5b9e\u73b0\uff09\uff0c\u7136\u540e\u6211\u4eec\u7684\u4ee3\u7801\u5c31\u7b80\u5355\u591a\u4e86\uff1a<\/p>\n
    \n
    template<\/span><typename<\/span> T>\r\nvoid<\/span> Test<\/span>(T &&t1, T &&t2)<\/span>\r\n<\/span>{\r\n  __Test(ForwardValue<T>(t1), ForwardValue<T>(t2));\r\n}\r\n<\/code><\/pre>\n<\/div>\n
    \u65e0\u8bba\u6211\u4eec\u7684__Test\u63a5\u53d7\u4ec0\u4e48\u5f62\u5f0f\u7684\u53c2\u6570\uff0c\u5373\u4f7f\u6709\u591a\u4e2a\u5f62\u5f0f\u7684__Test\uff0c\u90fd\u53ef\u4ee5\u8c03\u7528\u5230\u6b63\u786e\u7684__Test\u4e2d\uff0c\u4ece\u800c\u4e0d\u518d\u9700\u8981\u7279\u5316\u591a\u4e2a\u6a21\u677f\u51fd\u6570\uff0c\u8fd9\u5c31\u662f\u5b8c\u7f8e\u8f6c\u53d1\u3002<\/p>\n
    \u6240\u8c13\u5b8c\u7f8e\u8f6c\u53d1\uff1a\u65e0\u8bba\u76ee\u7684\u8c03\u7528\u51fd\u6570\u9700\u8981\u54ea\u79cd\u7c7b\u578b\u7684\u53c2\u6570\u90fd\u53ef\u4ee5\u6b63\u786e\u8c03\u7528\u5230\u6211\u4eec\u60f3\u8981\u7684\u90a3\u4e2a\u51fd\u6570\u91cc\u3002\u4e0amain\u7684\u793a\u4f8b\u4ee3\u7801\u4e2d\u51fa\u73b0\u4e86&&\uff0c\u6682\u4e14\u6211\u4eec\u628a&&\u8fd9\u4e2a\u53eb\u505a\u53f3\u503c\u5f15\u7528\u5427\u3002C++11\u4e2d\u5b9e\u73b0\u5b8c\u7f8e\u8f6c\u53d1\u662f\u4f9d\u9760\u7684\u7c7b\u578b\u63a8\u5bfc\u548c\u5f15\u7528\u6298\u53e0\u3002\u7c7b\u578b\u63a8\u5bfc\u4e0d\u7528\u591a\u8bf4\uff0cSTL\u4e2d\u7684\u5bb9\u5668\u5e7f\u6cdb\u4f7f\u7528\u4e86\u7c7b\u578b\u63a8\u5bfc\uff0c\u90a3\u5f15\u7528\u6298\u53e0\u5f0f\u4ec0\u4e48\uff1f<\/p>\n
    \u5f15\u7528\u6298\u53e0\u89c4\u5219\u5c31\u662f\u51fd\u6570\u63a5\u53d7\u53c2\u6570\u5f62\u5f0f\u4e0e\u4f20\u5165\u53c2\u6570\u5f62\u5f0f\u4e4b\u95f4\u8fdb\u884c\u5f15\u7528\u7b80\u5316\uff0c\u5177\u4f53\u7f16\u8bd1\u5668\u5b9a\u4e49\u4e86\u8fd9\u6837\u4e00\u6761\u89c4\u5219\uff1a<\/p>\n
    \n
    1. <\/span>T& + & => T&\r\n2. <\/span>T&& + & => T&\r\n3. <\/span>T& + && => T&\r\n4. <\/span>T&& + && => T&&\r\n<\/code><\/pre>\n<\/div>\n
    \u4e0a\u9762\u7684\u89c4\u5219\u4e2d\uff0c\u524d\u8005\u4ee3\u8868\u63a5\u53d7\u7c7b\u578b\uff0c\u540e\u8005\u4ee3\u8868\u8fdb\u5165\u7c7b\u578b\uff0c=>\u8868\u793a\u5f15\u7528\u6298\u53e0\u4e4b\u540e\u7684\u7c7b\u578b\uff0c\u5373\u6700\u540e\u88ab\u63a8\u5bfc\u51b3\u65ad\u7684\u7c7b\u578b\u3002<\/p>\n
    \u73b0\u5728\u6211\u4eec\u7528\u4e00\u6bb5\u5b9e\u4f8b\u4ee3\u7801\u6765\u770b\u770b\u5f15\u7528\u6298\u53e0\u662f\u600e\u4e48\u8fd0\u4f5c\u7684\u3002<\/p>\n
    \n
    template<\/span> <typename<\/span> T> \r\nstruct<\/span> Name;\r\n\r\ntemplate<\/span> <> \r\nstruct<\/span> Name<string<\/span>> \r\n{\r\n  static<\/span> const<\/span> char<\/span> * get() \r\n  {\r\n    return<\/span> \"string\"<\/span>;\r\n  }\r\n};\r\n\r\ntemplate<\/span> <> \r\nstruct<\/span> Name<const<\/span> string<\/span>> \r\n{\r\n  static<\/span> const<\/span> char<\/span> * get() \r\n  {\r\n    return<\/span> \"const string\"<\/span>;\r\n  }\r\n};\r\n\r\ntemplate<\/span> <> \r\nstruct<\/span> Name<string<\/span>&> \r\n{\r\n  static<\/span> const<\/span> char<\/span> * get() \r\n  {\r\n    return<\/span> \"string&\"<\/span>;\r\n  }\r\n};\r\n\r\ntemplate<\/span> <> \r\nstruct<\/span> Name<const<\/span> string<\/span>&> \r\n{\r\n  static<\/span> const<\/span> char<\/span> * get() \r\n  {\r\n    return<\/span> \"const string&\"<\/span>;\r\n  }\r\n};\r\n\r\ntemplate<\/span> <> \r\nstruct<\/span> Name<string<\/span>&&> \r\n{\r\n  static<\/span> const<\/span> char<\/span> * get() \r\n  {\r\n    return<\/span> \"string&&\"<\/span>;\r\n  }\r\n};\r\n\r\ntemplate<\/span> <> \r\nstruct<\/span> Name<const<\/span> string<\/span>&&> \r\n{\r\n  static<\/span> const<\/span> char<\/span> * get()\r\n  {\r\n    return<\/span> \"const string&&\"<\/span>;\r\n  }\r\n};\r\n\r\ntemplate<\/span> <typename<\/span> T> \r\nvoid<\/span> quark<\/span>(T&& t)<\/span> \r\n<\/span>{\r\n  cout<\/span> << \"**********************************\"<\/span> << endl;\r\n  cout<\/span> << \"t: \"<\/span> << t << endl;\r\n  cout<\/span> << \"T: \"<\/span> << Name<T>::get() << endl;  \/\/ -->A<\/span>\r\n  cout<\/span> << \"T&&: \"<\/span> << Name<T&&>::get() << endl;  \/\/ -->B<\/span>\r\n  cout<\/span> << endl;\r\n}\r\n\r\nstring<\/span> strange<\/span>()<\/span> \r\n<\/span>{\r\n  return<\/span> \"strange()\"<\/span>;\r\n}\r\n\r\nconst<\/span> string<\/span> charm<\/span>()<\/span> \r\n<\/span>{\r\n  return<\/span> \"charm()\"<\/span>;\r\n}\r\n\r\n\r\nint<\/span> main<\/span>()<\/span>\r\n<\/span>{\r\n  string<\/span> up<\/span>(\"up\")<\/span><\/span>;\r\n  const<\/span> string<\/span> down<\/span>(\"down\")<\/span><\/span>;\r\n  \r\n  quark(up);\t\/\/ -->1<\/span>\r\n  quark(down);\t\/\/ -->2<\/span>\r\n  quark(strange());\t\/\/ -->3<\/span>\r\n  quark(charm());\t\t\/\/ -->4<\/span>\r\n  \r\n  return<\/span> 0<\/span>;\r\n}\r\n<\/code><\/pre>\n<\/div>\n
    \u4ece\u4e0a\u9762\u7684\u5b9e\u4f8b\u4ee3\u7801\u5927\u81f4\u53ef\u4ee5\u77e5\u6653\u5f15\u7528\u6298\u53e0\u7684\u8fd0\u4f5c\u3002\u4e0a\u8ff0\u4ee3\u7801\u8fd0\u884c\u7ed3\u679c\uff1a<\/p>\n
    \n
    *****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>***<\/span>*\r\nt: up\r\nT: string&\r\nT&&: string&\r\n\r\n*****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>***<\/span>*\r\nt: down\r\nT: const string&\r\nT&&: const string&\r\n\r\n*****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>***<\/span>*\r\nt: strange()\r\nT: string\r\nT&&: string&&\r\n\r\n*****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>*****<\/span>***<\/span>*\r\nt: charm()\r\nT: const string\r\nT&&: const string&&\r\n<\/code><\/pre>\n<\/div>\n
      \n
    1. \u5728\u8c03\u7528quack\u65f6\uff0cup\u88ab\u63a8\u5bfc\u4e3astring&\u7c7b\u578b\u3002\u5728quack\u4e2d\uff0cT\u4f1a\u88ab\u63a8\u5bfc\u4e3astring&\u7c7b\u578b\uff0c\u6839\u636e T& + && -> T&\u89c4\u5219\uff0c\u4e5f\u5c31\u662f\u8bf4\u8fdb\u5165\u5230quack\u4e2d\uff0cT\u662fstring&\uff0c\u6240\u4ee5A\u8c03\u7528\u4e86string&\u7684\u7248\u672c\u3002\u4ecd\u7136\u662f\u4e0a\u8ff0\u89c4\u5219\uff0c\u5728\u6267\u884cB\u65f6\uff0cT\u4f9d\u65e7\u88ab\u8f6c\u6362\u548c\u63a8\u5bfc\u4e3astring&\uff0c\u6240\u4ee5\u5c31\u8d70\u5230\u4e86\u76f8\u5e94\u7684\u7248\u672c\u4e2d\u3002<\/li>\n
    2. \u56e0\u4e3adown\u5177\u6709const\u5c5e\u6027\uff0c\u6240\u4ee5\u8868\u73b0\u5f62\u5f0f\u4e0e1\u4e00\u6837\uff0c\u552f\u4e00\u7684\u533a\u522b\u662fA\u548cB\u5747\u8c03\u7528\u5230\u5177\u6709const\u5c5e\u6027\u7684\u7248\u672c\u3002<\/li>\n
    3. \u8fd9\u91cc\u6709\u70b9\u7279\u6b8a\uff0c\u56e0\u4e3astrange()\u8fd4\u56de\u7684\u662f\u4e34\u65f6\u5bf9\u8c61\uff0c\u7c7b\u578b\u4e3astring\uff0c\u56e0\u6b64\u8fdb\u5165quack\u4e4b\u540e\uff0cT\u4ecd\u65e7\u4e3astring\u7c7b\u578b\uff0c\u56e0\u6b64A\u6700\u7ec8\u4f1a\u8fdb\u5165string\u7684\u8c03\u7528\u7248\u672c\uff0c\u540c\u7406T&&\u5c31\u662fstring&&\uff0c\u4f1a\u8fdb\u5165\u5bf9\u5e94\u7684\u7248\u672c\u4e2d\u3002<\/li>\n
    4. \u8fd9\u91cc\u6709\u70b9\u7279\u6b8a\uff0c\u56e0\u4e3acharm()\u8fd4\u56de\u7684\u662f\u4e34\u65f6\u5bf9\u8c61\uff0c\u7c7b\u578b\u4e3astring\uff0c\u56e0\u6b64\u8fdb\u5165quack\u4e4b\u540e\uff0cT\u4e3astring\u7c7b\u578b\uff0c\u7531\u4e8e\u6709const\u5c5e\u6027\uff0c\u6240\u4ee5A\u548cB\u90fd\u4f1a\u8c03\u7528\u5230const\u5c5e\u6027\u7684\u7248\u672c\u3002<\/li>\n<\/ol>\n
      \u4e0a\u9762\u7684\u4ee3\u7801\u4e2d\u6211\u4eec\u7ed9\u51fa\u4e86std::forward\u7684\u5927\u81f4\u5b9e\u73b0\uff0c\u5176\u5b9e\u8bf4\u767d\u4e86\uff0c\u5c31\u662f\u5229\u7528\u5f15\u7528\u6298\u53e0\u89c4\u5219\u4fdd\u7559\u53c2\u6570\u539f\u59cb\u7c7b\u578b\uff0c\u62d2\u7edd\u7f16\u8bd1\u5668\u7684\u7c7b\u578b\u63a8\u5bfc\uff0c\u4ee5\u8fbe\u5230\u5c06\u53c2\u6570\u5b8c\u7f8e\u8f6c\u53d1\u5230\u76ee\u7684\u51fd\u6570\u4e2d\u3002<\/p>\n
      \u4e4b\u6240\u6709\u5b58\u5728\u5b8c\u7f8e\u8f6c\u53d1\uff0c\u5176\u95ee\u9898\u5b9e\u8d28\u662f\uff1a\u6a21\u677f\u53c2\u6570\u7c7b\u578b\u63a8\u5bfc\u5728\u8f6c\u53d1\u8fc7\u7a0b\u4e2d\u65e0\u6cd5\u4fdd\u8bc1\u5de6\u53f3\u503c\u7684\u5f15\u7528\u95ee\u9898\u3002\u800c\u5b8c\u7f8e\u8f6c\u53d1\u5c31\u662f\u5728\u4e0d\u7834\u574fconst\u5c5e\u6027\u7684\u524d\u63d0\u4e0b\u901a\u8fc7\u589e\u52a0\u5de6\u53f3\u503c\u5f15\u7528\u6982\u5ff5\u548c\u65b0\u589e\u53c2\u6570\u63a8\u5bfc\u89c4\u5219\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n
      std::forward\u7684\u5173\u952e\u5b57\uff1a\u89e3\u51b3<\/h5>\n
      \u5728\u6a21\u677f\u5185\uff0c\u5982\u679c\u6211\u4eec\u9700\u8981\u5c06\u4e00\u7ec4\u53c2\u6570\u539f\u5c01\u4e0d\u52a8\u7684\u4f20\u9012\u7ed9\u53e6\u5916\u4e00\u4e2a\u53c2\u6570\uff0c\u5728\u6ca1\u6709\u5b8c\u7f8e\u8f6c\u53d1\u7684\u60c5\u51b5\u4e0b\uff0c\u8003\u8651\u53c2\u6570\u4f1a\u6709\u591a\u79cd\u7c7b\u578b\u7684\u91cd\u8f7d\uff0c\u56e0\u6b64\u5728\u6ca1\u6709\u5b8c\u7f8e\u8f6c\u53d1\u7684\u60c5\u51b5\u4e0b\uff0c\u91cd\u8f7d\u51fd\u6570\u4e2a\u6570\u5c06\u4f1a\u8fbe\u52302^n\u4e2a\uff0c\u591a\u4e48\u5e9e\u5927\u7684\u4eba\u5de5\u91cf\u3002\u5f53\u4f7f\u7528std::forward\u8f85\u4ee5\u6a21\u677f\u53c2\u6570\u63a8\u5bfc\u89c4\u5219\u4ee5\u4fdd\u6301\u53c2\u6570\u5c5e\u6027\u4e0d\u53d8\uff0c\u5b9e\u73b0\u5b8c\u7f8e\u8f6c\u53d1\u8282\u7701\u4e86\u5927\u91cf\u7684\u5de5\u4f5c\u3002<\/p>\n
      \u6ce8\uff1a<\/strong>\u4ee5\u4e0a\u4ee3\u7801\u5747\u5728VS2015 + Win10\u4e0a\u6d4b\u8bd5\u3002<\/p>\n<\/article>\n","protected":false},"excerpt":{"rendered":"
      \u8be6\u89e3C++11\u4e2d\u79fb\u52a8\u8bed\u4e49(std::mo<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[118],"class_list":["post-1371","post","type-post","status-publish","format-standard","hentry","tag-02-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1371","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=1371"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/1371\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=1371"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=1371"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=1371"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}