[{"data":1,"prerenderedAt":233},["ShallowReactive",2],{"archive-2024-4-1":3},{"title":4,"articles":5,"hot_article":18,"month_arch":81,"total":229,"cover":230},"2024年4月 - 独孤影的博客",[6],{"id":7,"title":8,"uri":9,"author":10,"tags":11,"created_at":15,"view_count":16,"content":17},118,"初学rust，多线程中读写全局变量","read-and-write-global-var-in-multi-thread-for-rust","duguying",[12,13,14],"全局变量","读写","rust","2024-04-25 22:51:33",286,"\u003Cp>参考上一篇\u003Ca href=\"https:\u002F\u002Fwww.duguying.net\u002Farticle\u002Frust-how-to-set-and-get-global-variable-in-runtime\">《初学rust，如何实现在运行时对全局变量设置和读取》\u003C\u002Fa>，文章中说，可以用\u003Ccode class=\"inline-code\">OnceCell\u003C\u002Fcode>来定义全局变量，然后就可以对全局变量进行读写，实际上，我发现\u003Ccode class=\"inline-code\">OnceCell\u003C\u002Fcode>的\u003Ccode class=\"inline-code\">set()\u003C\u002Fcode>方法只能调用一次，如果你试图第二次调用\u003Ccode class=\"inline-code\">set()\u003C\u002Fcode>来修改已经设定好的值，将会报错，设置值就失败了。\u003C\u002Fp>\n\n\u003Cp>由于这一切都是为了读写的并发安全。所以\u003Ccode class=\"inline-code\">OnceCell\u003C\u002Fcode>是无法实现读写全局变量的。要实现读写全局变量，应该使用\u003Ccode class=\"inline-code\">RwLock\u003C\u002Fcode>。如下\u003C\u002Fp>\n\n\u003Cp>定义全局变量\u003C\u002Fp>\n\n\u003Cpre style=\"color:#e6edf3;background-color:#0d1117;white-space:pre-wrap;word-break:break-word;\">\u003Ccode>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#ff7b72\">static\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#79c0ff;font-weight:bold\">WORKER_PID\u003C\u002Fspan>: \u003Cspan style=\"color:#f0883e;font-weight:bold\">RwLock\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\"><\u003C\u002Fspan>Option\u003Cspan style=\"color:#ff7b72;font-weight:bold\"><\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">u32\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">>\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">>\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>RwLock::new(None);\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fpre>\n\n\u003Cp>读写全局变量\u003C\u002Fp>\n\n\u003Cpre style=\"color:#e6edf3;background-color:#0d1117;white-space:pre-wrap;word-break:break-word;\">\u003Ccode>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#8b949e;font-style:italic\">\u002F\u002F 写入\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#8b949e;font-style:italic\">\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">fn\u003C\u002Fspan> \u003Cspan style=\"color:#d2a8ff;font-weight:bold\">store_worker_pid\u003C\u002Fspan>(pid: \u003Cspan style=\"color:#ff7b72\">u32\u003C\u002Fspan>)\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>{\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#6e7681\">\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\">    \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">let\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">mut\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>data\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#79c0ff;font-weight:bold\">WORKER_PID\u003C\u002Fspan>.write().unwrap();\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#6e7681\">\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\">    \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">*\u003C\u002Fspan>data\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>Some(pid);\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#6e7681\">\u003C\u002Fspan>}\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#6e7681\">\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#6e7681\">\u003C\u002Fspan>\u003Cspan style=\"color:#8b949e;font-style:italic\">\u002F\u002F 读取\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#8b949e;font-style:italic\">\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">let\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>data\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#79c0ff;font-weight:bold\">WORKER_PID\u003C\u002Fspan>.read().unwrap();\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\u003Cspan style=\"color:#6e7681\">\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">let\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>cpid\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>data.unwrap();\u003Cspan style=\"color:#6e7681\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fpre>\n\n\u003Cp>这里的读写就可以多次进行了。可以看到，这里使用了读写锁，写的时候会先通过\u003Ccode class=\"inline-code\">write()\u003C\u002Fcode>方法获取写入锁实例，然后对其赋值写入。读取的时候会先通过\u003Ccode class=\"inline-code\">read()\u003C\u002Fcode>方法获取读取锁实例，然后取里面的值。这样一来就实现了全局变量的读写。\u003C\u002Fp>\n",{"title":19,"list":20},"最热文章",[21,27,33,39,45,51,57,63,69,75],{"id":22,"title":23,"uri":24,"author":10,"created_at":25,"view_count":26},28,"docker容器目录与主机目录同步","\u002Farticle\u002Fdocker容器目录与主机目录同步","2014-12-31 12:34:08",15570,{"id":28,"title":29,"uri":30,"author":10,"created_at":31,"view_count":32},21,"beego中使用fis","\u002Farticle\u002Fbeego中使用fis","2014-12-03 10:47:56",9250,{"id":34,"title":35,"uri":36,"author":10,"created_at":37,"view_count":38},20,"用github登录，oauth开发","\u002Farticle\u002F用github登录，oauth开发","2014-11-23 13:33:37",9113,{"id":40,"title":41,"uri":42,"author":10,"created_at":43,"view_count":44},18,"windows服务注册工具nssm","\u002Farticle\u002Fwindows服务注册工具nssm","2014-10-31 21:34:39",9047,{"id":46,"title":47,"uri":48,"author":10,"created_at":49,"view_count":50},49,"用latex排版中文书籍","\u002Farticle\u002F用latex排版中文书籍","2016-10-31 11:12:02",8634,{"id":52,"title":53,"uri":54,"author":10,"created_at":55,"view_count":56},19,"texlive中文书签乱码","\u002Farticle\u002Ftexlive中文书签乱码","2014-11-15 02:54:01",8461,{"id":58,"title":59,"uri":60,"author":10,"created_at":61,"view_count":62},6,"Windows上的软件包管理器chocolatey","\u002Farticle\u002FWindows上的软件包管理器chocolatey","2014-08-10 15:55:22",8009,{"id":64,"title":65,"uri":66,"author":10,"created_at":67,"view_count":68},3,"利用开源和免费资源搭建CI环境","\u002Farticle\u002F利用开源和免费资源搭建CI环境","2014-07-04 16:54:58",7732,{"id":70,"title":71,"uri":72,"author":10,"created_at":73,"view_count":74},16,"php-fpm网站目录权限配置","\u002Farticle\u002Fphp-fpm网站目录权限配置","2014-10-18 01:36:10",7274,{"id":76,"title":77,"uri":78,"author":10,"created_at":79,"view_count":80},27,"sublime text 2插件开发，外部修改文件无法重新加载","\u002Farticle\u002Fsublime text 2插件开发，外部修改文件无法重新加载","2014-12-26 20:24:13",7054,{"title":82,"list":83},"按月归档",[84,88,91,94,97,100,103,107,111,114,117,120,124,127,130,134,137,140,143,147,150,153,156,159,162,165,168,171,174,177,180,183,186,189,192,195,198,201,204,207,211,214,217,220,223,226],{"title":85,"uri":86,"view_count":87},"2026年7月","\u002Farchive\u002F2026\u002F7\u002F1","[1]",{"title":89,"uri":90,"view_count":87},"2026年1月","\u002Farchive\u002F2026\u002F1\u002F1",{"title":92,"uri":93,"view_count":87},"2025年4月","\u002Farchive\u002F2025\u002F4\u002F1",{"title":95,"uri":96,"view_count":87},"2024年6月","\u002Farchive\u002F2024\u002F6\u002F1",{"title":98,"uri":99,"view_count":87},"2024年5月","\u002Farchive\u002F2024\u002F5\u002F1",{"title":101,"uri":102,"view_count":87},"2024年4月","\u002Farchive\u002F2024\u002F4\u002F1",{"title":104,"uri":105,"view_count":106},"2023年12月","\u002Farchive\u002F2023\u002F12\u002F1","[6]",{"title":108,"uri":109,"view_count":110},"2023年11月","\u002Farchive\u002F2023\u002F11\u002F1","[2]",{"title":112,"uri":113,"view_count":87},"2023年10月","\u002Farchive\u002F2023\u002F10\u002F1",{"title":115,"uri":116,"view_count":87},"2023年7月","\u002Farchive\u002F2023\u002F7\u002F1",{"title":118,"uri":119,"view_count":110},"2023年6月","\u002Farchive\u002F2023\u002F6\u002F1",{"title":121,"uri":122,"view_count":123},"2023年5月","\u002Farchive\u002F2023\u002F5\u002F1","[3]",{"title":125,"uri":126,"view_count":110},"2023年4月","\u002Farchive\u002F2023\u002F4\u002F1",{"title":128,"uri":129,"view_count":110},"2023年3月","\u002Farchive\u002F2023\u002F3\u002F1",{"title":131,"uri":132,"view_count":133},"2023年2月","\u002Farchive\u002F2023\u002F2\u002F1","[5]",{"title":135,"uri":136,"view_count":87},"2023年1月","\u002Farchive\u002F2023\u002F1\u002F1",{"title":138,"uri":139,"view_count":110},"2022年12月","\u002Farchive\u002F2022\u002F12\u002F1",{"title":141,"uri":142,"view_count":133},"2022年11月","\u002Farchive\u002F2022\u002F11\u002F1",{"title":144,"uri":145,"view_count":146},"2022年10月","\u002Farchive\u002F2022\u002F10\u002F1","[4]",{"title":148,"uri":149,"view_count":106},"2022年9月","\u002Farchive\u002F2022\u002F9\u002F1",{"title":151,"uri":152,"view_count":133},"2022年8月","\u002Farchive\u002F2022\u002F8\u002F1",{"title":154,"uri":155,"view_count":87},"2019年7月","\u002Farchive\u002F2019\u002F7\u002F1",{"title":157,"uri":158,"view_count":87},"2019年2月","\u002Farchive\u002F2019\u002F2\u002F1",{"title":160,"uri":161,"view_count":87},"2018年9月","\u002Farchive\u002F2018\u002F9\u002F1",{"title":163,"uri":164,"view_count":87},"2018年8月","\u002Farchive\u002F2018\u002F8\u002F1",{"title":166,"uri":167,"view_count":87},"2017年11月","\u002Farchive\u002F2017\u002F11\u002F1",{"title":169,"uri":170,"view_count":87},"2017年8月","\u002Farchive\u002F2017\u002F8\u002F1",{"title":172,"uri":173,"view_count":87},"2017年5月","\u002Farchive\u002F2017\u002F5\u002F1",{"title":175,"uri":176,"view_count":87},"2017年4月","\u002Farchive\u002F2017\u002F4\u002F1",{"title":178,"uri":179,"view_count":87},"2016年11月","\u002Farchive\u002F2016\u002F11\u002F1",{"title":181,"uri":182,"view_count":87},"2016年10月","\u002Farchive\u002F2016\u002F10\u002F1",{"title":184,"uri":185,"view_count":110},"2016年9月","\u002Farchive\u002F2016\u002F9\u002F1",{"title":187,"uri":188,"view_count":87},"2016年8月","\u002Farchive\u002F2016\u002F8\u002F1",{"title":190,"uri":191,"view_count":110},"2016年7月","\u002Farchive\u002F2016\u002F7\u002F1",{"title":193,"uri":194,"view_count":133},"2016年6月","\u002Farchive\u002F2016\u002F6\u002F1",{"title":196,"uri":197,"view_count":87},"2015年12月","\u002Farchive\u002F2015\u002F12\u002F1",{"title":199,"uri":200,"view_count":87},"2015年10月","\u002Farchive\u002F2015\u002F10\u002F1",{"title":202,"uri":203,"view_count":110},"2015年2月","\u002Farchive\u002F2015\u002F2\u002F1",{"title":205,"uri":206,"view_count":87},"2015年1月","\u002Farchive\u002F2015\u002F1\u002F1",{"title":208,"uri":209,"view_count":210},"2014年12月","\u002Farchive\u002F2014\u002F12\u002F1","[8]",{"title":212,"uri":213,"view_count":110},"2014年11月","\u002Farchive\u002F2014\u002F11\u002F1",{"title":215,"uri":216,"view_count":133},"2014年10月","\u002Farchive\u002F2014\u002F10\u002F1",{"title":218,"uri":219,"view_count":123},"2014年9月","\u002Farchive\u002F2014\u002F9\u002F1",{"title":221,"uri":222,"view_count":123},"2014年8月","\u002Farchive\u002F2014\u002F8\u002F1",{"title":224,"uri":225,"view_count":123},"2014年7月","\u002Farchive\u002F2014\u002F7\u002F1",{"title":227,"uri":228,"view_count":110},"2013年9月","\u002Farchive\u002F2013\u002F9\u002F1",1,{"url":231,"title":232},"https:\u002F\u002Fimage.duguying.net\u002F2022\u002F09\u002Fij6x8o4s.webp","老家 摄于2020年秋",1790062261493]