{"id":5287,"date":"2021-05-31T15:51:06","date_gmt":"2021-05-31T07:51:06","guid":{"rendered":"https:\/\/damogame.cn\/wordpress\/?p=5287"},"modified":"2021-05-31T15:51:06","modified_gmt":"2021-05-31T07:51:06","slug":"c%e4%b8%ad%e7%9a%84raii%e4%bb%8b%e7%bb%8d","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/5287","title":{"rendered":"C++\u4e2d\u7684RAII\u4ecb\u7ecd"},"content":{"rendered":"
<\/div>\n
\n
RAII\u6280\u672f\u88ab\u8ba4\u4e3a\u662fC++\u4e2d\u7ba1\u7406\u8d44\u6e90\u7684\u6700\u4f73\u65b9\u6cd5\uff0c\u8fdb\u4e00\u6b65\u5f15\u7533\uff0c\u4f7f\u7528RAII\u6280\u672f\u4e5f\u53ef\u4ee5\u5b9e\u73b0\u5b89\u5168\u3001\u7b80\u6d01\u7684\u72b6\u6001\u7ba1\u7406\uff0c\u7f16\u5199\u51fa\u4f18\u96c5\u7684\u5f02\u5e38\u5b89\u5168\u7684\u4ee3\u7801\u3002<\/div>\n
\n

\u6458\u8981<\/h2>\n

RAII\u6280\u672f\u88ab\u8ba4\u4e3a\u662fC++\u4e2d\u7ba1\u7406\u8d44\u6e90\u7684\u6700\u4f73\u65b9\u6cd5\uff0c\u8fdb\u4e00\u6b65\u5f15\u7533\uff0c\u4f7f\u7528RAII\u6280\u672f\u4e5f\u53ef\u4ee5\u5b9e\u73b0\u5b89\u5168\u3001\u7b80\u6d01\u7684\u72b6\u6001\u7ba1\u7406\uff0c\u7f16\u5199\u51fa\u4f18\u96c5\u7684\u5f02\u5e38\u5b89\u5168\u7684\u4ee3\u7801\u3002<\/p>\n

\u8d44\u6e90\u7ba1\u7406<\/h2>\n

RAII\u662fC++\u7684\u53d1\u660e\u8005Bjarne Stroustrup\u63d0\u51fa\u7684\u6982\u5ff5\uff0cRAII\u5168\u79f0\u662f\u201cResource Acquisition is Initialization\u201d\uff0c\u76f4\u8bd1\u8fc7\u6765\u662f\u201c\u8d44\u6e90\u83b7\u53d6\u5373\u521d\u59cb\u5316\u201d\uff0c\u4e5f\u5c31\u662f\u8bf4\u5728\u6784\u9020\u51fd\u6570\u4e2d\u7533\u8bf7\u5206\u914d\u8d44\u6e90\uff0c\u5728\u6790\u6784\u51fd\u6570\u4e2d\u91ca\u653e\u8d44\u6e90\u3002\u56e0\u4e3aC++\u7684\u8bed\u8a00\u673a\u5236\u4fdd\u8bc1\u4e86\uff0c\u5f53\u4e00\u4e2a\u5bf9\u8c61\u521b\u5efa\u7684\u65f6\u5019\uff0c\u81ea\u52a8\u8c03\u7528\u6784\u9020\u51fd\u6570\uff0c\u5f53\u5bf9\u8c61\u8d85\u51fa\u4f5c\u7528\u57df\u7684\u65f6\u5019\u4f1a\u81ea\u52a8\u8c03\u7528\u6790\u6784\u51fd\u6570\u3002\u6240\u4ee5\uff0c\u5728RAII\u7684\u6307\u5bfc\u4e0b\uff0c\u6211\u4eec\u5e94\u8be5\u4f7f\u7528\u7c7b\u6765\u7ba1\u7406\u8d44\u6e90\uff0c\u5c06\u8d44\u6e90\u548c\u5bf9\u8c61\u7684\u751f\u547d\u5468\u671f\u7ed1\u5b9a\u3002<\/p>\n

\u667a\u80fd\u6307\u9488\uff08std::shared_ptr\u548cstd::unique_ptr\uff09\u5373RAII\u6700\u5177\u4ee3\u8868\u7684\u5b9e\u73b0\uff0c\u4f7f\u7528\u667a\u80fd\u6307\u9488\uff0c\u53ef\u4ee5\u5b9e\u73b0\u81ea\u52a8\u7684\u5185\u5b58\u7ba1\u7406\uff0c\u518d\u4e5f\u4e0d\u9700\u8981\u62c5\u5fc3\u5fd8\u8bb0delete\u9020\u6210\u7684\u5185\u5b58\u6cc4\u6f0f\u3002\u6beb\u4e0d\u5938\u5f20\u7684\u6765\u8bb2\uff0c\u6709\u4e86\u667a\u80fd\u6307\u9488\uff0c\u4ee3\u7801\u4e2d\u51e0\u4e4e\u4e0d\u9700\u8981\u518d\u51fa\u73b0delete\u4e86\u3002<\/p>\n

\u5185\u5b58\u53ea\u662f\u8d44\u6e90\u7684\u4e00\u79cd\uff0c\u5728\u8fd9\u91cc\u6211\u4eec\u8ba8\u8bba\u4e00\u4e0b\u66f4\u52a0\u5e7f\u4e49\u7684\u8d44\u6e90\u7ba1\u7406\u3002\u6bd4\u5982\u8bf4\u6587\u4ef6\u7684\u6253\u5f00\u4e0e\u5173\u95ed\u3001windows\u4e2d\u53e5\u67c4\u7684\u83b7\u53d6\u4e0e\u91ca\u653e\u7b49\u7b49\u3002\u6309\u7167\u5e38\u89c4\u7684RAII\u6280\u672f\u9700\u8981\u5199\u4e00\u5806\u7ba1\u7406\u5b83\u4eec\u7684\u7c7b\uff0c\u6709\u7684\u65f6\u5019\u663e\u5f97\u6bd4\u8f83\u9ebb\u70e6\u3002\u4f46\u662f\u5982\u679c\u624b\u52a8\u91ca\u653e\uff0c\u901a\u5e38\u8fd8\u8981\u8003\u8651\u5404\u79cd\u5f02\u5e38\u5904\u7406\uff0c\u6bd4\u5982\u8bf4\uff1a<\/p>\n

\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n
void function()\r\n{\r\n    FILE *f = fopen(\"test.txt\", 'r');\r\n    if (.....)\r\n    {\r\n        fclose(f);\r\n        return;\r\n    }\r\n    else if(.....)\r\n    {\r\n        fclose(f);\r\n        return;\r\n    }\r\n\r\n    fclose(f);\r\n    ......\r\n}<\/pre>\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n<\/div>\n
\u8fd9\u91cc\u4ecb\u7ecd\u4e00\u4e2a\u7f51\u4e0a\u5b9e\u73b0\u7684\u6211\u8ba4\u4e3a\u6bd4\u8f83\u7b80\u6d01\u7684\u65b9\u6cd5\uff0c\u6587\u7ae0\u5728\u8fd9\u91cc<\/a>\u3002\u4f5c\u8005\u4f7f\u7528\u4e86C++11\u6807\u51c6\u4e2d\u7684lambda\u8868\u8fbe\u5f0f\u548cstd::function\u76f8\u7ed3\u5408\u7684\u65b9\u6cd5\uff0c\u975e\u5e38\u7b80\u6d01\u3001\u660e\u4e86\u3002\u76f4\u63a5\u770b\u4ee3\u7801\u5427\uff1a<\/p>\n
\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n
#define SCOPEGUARD_LINENAME_CAT(name, line) name##line\r\n#define SCOPEGUARD_LINENAME(name, line) SCOPEGUARD_LINENAME_CAT(name, line)\r\n#define ON_SCOPE_EXIT(callback) ScopeGuard SCOPEGUARD_LINENAME(EXIT, __LINE__)(callback)\r\n\r\nclass ScopeGuard\r\n{\r\npublic:\r\n    explicit ScopeGuard(std::function<void()> f) : \r\n        handle_exit_scope_(f){};\r\n\r\n    ~ScopeGuard(){ handle_exit_scope_(); }\r\nprivate:\r\n    std::function<void()> handle_exit_scope_;\r\n};\r\n\r\nint main()\r\n{\r\n    {\r\n        A *a = new A();\r\n        ON_SCOPE_EXIT([&] {delete a; });\r\n        ......\r\n    }\r\n\r\n    {\r\n        std::ofstream f(\"test.txt\");\r\n        ON_SCOPE_EXIT([&] {f.close(); });\r\n        ......\r\n    }\r\n\r\n    system(\"pause\");\r\n    return 0;\r\n}<\/pre>\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n<\/div>\n
\u4f5c\u8005\u4e3a\u4e86\u4f7f\u7528\u65b9\u4fbf\uff0c\u8fd8\u5b9a\u4e49\u4e86\u6839\u636e\u884c\u53f7\u6765\u5bf9ScopeGuard\u7c7b\u578b\u5bf9\u8c61\u547d\u540d\u7684\u5b8f\u5b9a\u4e49\u3002\u770b\u5230\u4e86\u5427\uff0c\u5f53ScopeGuard\u5bf9\u8c61\u8d85\u51fa\u4f5c\u7528\u57df\uff0cScopeGuard\u7684\u6790\u6784\u51fd\u6570\u4e2d\u4f1a\u8c03\u7528handle_exit_scope_\u51fd\u6570\uff0c\u4e5f\u5c31\u662flambda\u8868\u8fbe\u5f0f\u4e2d\u7684\u5185\u5bb9\uff0c\u6240\u4ee5\u5728lamabda\u8868\u8fbe\u5f0f\u4e2d\u586b\u4e0a\u8d44\u6e90\u91ca\u653e\u7684\u4ee3\u7801\u5373\u53ef\uff0c\u591a\u4e48\u7b80\u6d01\u3001\u660e\u4e86\u3002\u65e2\u4e0d\u9700\u8981\u4e3a\u6bcf\u79cd\u8d44\u6e90\u7ba1\u7406\u5355\u72ec\u5199\u5bf9\u5e94\u7684\u7ba1\u7406\u7c7b\uff0c\u4e5f\u4e0d\u9700\u8981\u8003\u8651\u624b\u52a8\u91ca\u653e\u51fa\u73b0\u5404\u79cd\u5f02\u5e38\u60c5\u51b5\u4e0b\u7684\u5904\u7406\uff0c\u540c\u65f6\u8d44\u6e90\u7684\u7533\u8bf7\u548c\u91ca\u653e\u653e\u5728\u4e00\u8d77\u53bb\u5199\uff0c\u6c38\u8fdc\u4e0d\u4f1a\u5fd8\u8bb0\u3002<\/p>\n
\u72b6\u6001\u7ba1\u7406<\/h2>\n
RAII\u53e6\u4e00\u4e2a\u5f15\u7533\u7684\u5e94\u7528\u662f\u53ef\u4ee5\u5b9e\u73b0\u5b89\u5168\u7684\u72b6\u6001\u7ba1\u7406\u3002\u4e00\u4e2a\u5178\u578b\u7684\u5e94\u7528\u5c31\u662f\u5728\u7ebf\u7a0b\u540c\u6b65\u4e2d\uff0c\u4f7f\u7528std::unique_lock\u6216\u8005std::lock_guard\u5bf9\u4e92\u65a5\u91cfstd:: mutex\u8fdb\u884c\u72b6\u6001\u7ba1\u7406\u3002\u901a\u5e38\u6211\u4eec\u4e0d\u4f1a\u5199\u51fa\u5982\u4e0b\u7684\u4ee3\u7801\uff1a<\/p>\n
\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n
std::mutex mutex_;\r\nvoid function()\r\n{\r\n    mutex_.lock();\r\n    ......\r\n    ......\r\n    mutex_.unlock();\r\n}<\/pre>\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n<\/div>\n
\u56e0\u4e3a\uff0c\u5728\u4e92\u65a5\u91cflock\u548cunlock\u4e4b\u95f4\u7684\u4ee3\u7801\u5f88\u53ef\u80fd\u4f1a\u51fa\u73b0\u5f02\u5e38\uff0c\u6216\u8005\u6709return\u8bed\u53e5\uff0c\u8fd9\u6837\u7684\u8bdd\uff0c\u4e92\u65a5\u91cf\u5c31\u4e0d\u4f1a\u6b63\u786e\u7684unlock\uff0c\u4f1a\u5bfc\u81f4\u7ebf\u7a0b\u7684\u6b7b\u9501\u3002\u6240\u4ee5\u6b63\u786e\u7684\u65b9\u5f0f\u662f\u4f7f\u7528std::unique_lock\u6216\u8005std::lock_guard\u5bf9\u4e92\u65a5\u91cf\u8fdb\u884c\u72b6\u6001\u7ba1\u7406\uff1a<\/p>\n
\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n
std::mutex mutex_;\r\nvoid function()\r\n{\r\n    std::lock_guard<std::mutex> lock(mutex_);\r\n    ......\r\n    ......\r\n}<\/pre>\n
\"\u590d\u5236\u4ee3\u7801\"<\/a><\/span><\/div>\n<\/div>\n
\u5728\u521b\u5efastd::lock_guard\u5bf9\u8c61\u7684\u65f6\u5019\uff0c\u4f1a\u5bf9std::mutex\u5bf9\u8c61\u8fdb\u884clock\uff0c\u5f53std::lock_guard\u5bf9\u8c61\u5728\u8d85\u51fa\u4f5c\u7528\u57df\u65f6\uff0c\u4f1a\u81ea\u52a8std::mutex\u5bf9\u8c61\u8fdb\u884c\u89e3\u9501\uff0c\u8fd9\u6837\u7684\u8bdd\uff0c\u5c31\u4e0d\u7528\u62c5\u5fc3\u4ee3\u7801\u5f02\u5e38\u9020\u6210\u7684\u7ebf\u7a0b\u6b7b\u9501\u3002<\/p>\n
\u603b\u7ed3<\/h2>\n
\u901a\u8fc7\u4e0a\u9762\u7684\u5206\u6790\u53ef\u4ee5\u770b\u51fa\uff0cRAII\u7684\u6838\u5fc3\u601d\u60f3\u662f\u5c06\u8d44\u6e90\u6216\u8005\u72b6\u6001\u4e0e\u5bf9\u8c61\u7684\u751f\u547d\u5468\u671f\u7ed1\u5b9a\uff0c\u901a\u8fc7C++\u7684\u8bed\u8a00\u673a\u5236\uff0c\u5b9e\u73b0\u8d44\u6e90\u548c\u72b6\u6001\u7684\u5b89\u5168\u7ba1\u7406\u3002\u7406\u89e3\u548c\u4f7f\u7528RAII\u80fd\u4f7f\u8f6f\u4ef6\u8bbe\u8ba1\u66f4\u6e05\u6670\uff0c\u4ee3\u7801\u66f4\u5065\u58ee\u3002<\/p>\n
\u53c2\u8003<\/h2>\n
1\u3001http:\/\/mindhacks.cn\/2012\/08\/27\/modern-cpp-practices\/<\/a><\/p>\n
2\u3001http:\/\/www.jellythink.com\/archives\/101<\/a><\/p>\n
3\u3001http:\/\/www.cppblog.com\/aaxron\/archive\/2011\/03\/22\/142475.html<\/a><\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
RAII\u6280\u672f\u88ab\u8ba4\u4e3a\u662fC++\u4e2d\u7ba1\u7406\u8d44\u6e90\u7684\u6700<\/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":[119],"class_list":["post-5287","post","type-post","status-publish","format-standard","hentry","tag-03-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/5287","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=5287"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/5287\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=5287"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=5287"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=5287"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}