[{"data":1,"prerenderedAt":242},["ShallowReactive",2],{"archive-2023-11-1":3},{"title":4,"articles":5,"hot_article":27,"month_arch":90,"total":238,"cover":239},"2023年11月 - 独孤影的博客",[6,16],{"id":7,"title":8,"uri":9,"author":10,"tags":11,"created_at":13,"view_count":14,"content":15},109,"初识串口","first-time-debug-serial-port","duguying",[12],"串口","2023-11-28 08:49:22",152,"\u003Cp>一直很想了解设备驱动编程。所以就从最基础，最简单的设备开始了解。串口，应该是所有设备中最简单最常见的设备。在linux中，有一种最简单的串口设备在\u003Ccode class=\"inline-code\">\u002Fdev\u003C\u002Fcode>下表现的是字符设备（c），字符设备可以被打开并且读写。\u003C\u002Fp>\n\n\u003Cp>我认识的第一个最简单的串口设备是一个usb接口的gps模块，如下图\n\u003Cimg src=\"https:\u002F\u002Fimage.duguying.net\u002F2023\u002F11\u002Ffmvi8se8.webp\" alt=\"fmvi8se8\" \u002F>\n它是我目前为止，用过的最简单的串口设备，它只需要读，无需写，单向通讯，我只需要打开字符设备，然后不停的从中读取数据就可以了，里面的数据是GPS定位信息相关的字符串，根据它的文档，进行字段解析，就能获取到经纬度、时间、角度、速度等信息。我曾经用golang写过一个一个程序获取这些信息\n\u003Cimg src=\"https:\u002F\u002Fimage.duguying.net\u002F2023\u002F11\u002Fsbtao9zf.png\" alt=\"sbtao9zf\" \u002F>\n这个程序，实际上可以算是一个用户态的设备驱动程序。\u003C\u002Fp>\n\n\u003Cp>我认识的第二个串口设备是一套蓝牙模块，用了usb转串口线连接蓝牙模块\n\u003Cimg src=\"https:\u002F\u002Fimage.duguying.net\u002F2023\u002F11\u002Fddlsq0na.webp\" alt=\"ddlsq0na\" \u002F>\n按照设备的文档，我将它通过usb转串口线连接，然后将usb插上电脑，成功识别到串口。然后手机通过客服提供的调试app连接蓝牙信号，电脑上用串口读写软件将串口打开，手机上发送信息，电脑串口上能收到信息，电脑串口上还能发送特定的AT指令对设备进行查询与设置。\n\u003Cimg src=\"https:\u002F\u002Fimage.duguying.net\u002F2023\u002F11\u002F3wwg8uas.webp\" alt=\"3wwg8uas\" \u002F>\n值得注意的是，我在连接模块的过程中，将usb转串口上的tx连接了模块tx，rx连接了模块的rx，导致无法收发消息，客服帮我找出问题并告诉我应该将tx连接rx，rx连接tx。想到这一点我恍然大悟，这跟rust里的\u003Ccode class=\"inline-code\">channel\u003C\u002Fcode>，go里的\u003Ccode class=\"inline-code\">chan\u003C\u002Fcode>，以及linux上的通用管道一样，都属于管道模型，对端的输出接入到设备的输入，对端才能将信息传给设备。后续我想我会进一步对这个蓝牙模块编写用户态驱动程序，进而尝试编写内核态驱动程序。\u003C\u002Fp>\n\n\u003Cp>其实早在我认识GPS串口设备之前，我也试过温湿度传感器DHT22，但是，这玩意儿根本不是串口，它只有一个数据接口(DATA)，也就是不像串口那样分rx,tx，它需要通过gpio口连接DATA针，然后通过高电位低电位来实现双向通讯，从而获取到温湿度数据。它既然不是串口设备那么也不能作为通用设备直插一般的电脑了。\u003C\u002Fp>\n\n\u003Cp>在我看来，程序能驱动物理设备，也是一件很有趣的事情。\u003C\u002Fp>\n",{"id":17,"title":18,"uri":19,"author":10,"tags":20,"created_at":24,"view_count":25,"content":26},108,"初学rust，如何实现在运行时对全局变量设置和读取","rust-how-to-set-and-get-global-variable-in-runtime",[21,22,23],"运行时","全局变量","读写","2023-11-01 22:11:16",599,"\u003Cp>在rust中，如何实现在运行时对全局变量设置和读取，这个问题困扰了我一段时间。因为在rust中，全局变量是不能在运行时修改的。rust的全局变量是属于全局静态变量，使用关键词\u003Ccode class=\"inline-code\">static\u003C\u002Fcode>来定义，如下：\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:#ff7b72\">mut\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>count: \u003Cspan style=\"color:#ff7b72\">usize\u003C\u002Fspan> \u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#a5d6ff\">0\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:#ff7b72\">pub\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">fn\u003C\u002Fspan> \u003Cspan style=\"color:#d2a8ff;font-weight:bold\">init_config\u003C\u002Fspan>(file_path: \u003Cspan style=\"color:#79c0ff\">&\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">str\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>count\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>count\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">+\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#a5d6ff\">1\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>\u003C\u002Fcode>\u003C\u002Fpre>\n\n\u003Cp>编译器会告诉你修改\u003Ccode class=\"inline-code\">count\u003C\u002Fcode>不安全(unsafe)。\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>➜  las git:(feature\u002Fself-update-with-watcher-fork) ✗ cargo build\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   Compiling las v0.1.1 (\u002Froot\u002Fcode\u002Flas)\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>error[E0133]: use of mutable static is unsafe and requires unsafe function or block\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>  --> src\u002Fconfig\u002Fcfg.rs:35:13\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   |\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>35 |     count = count + 1;\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   |             ^^^^^ use of mutable static\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   |\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>error[E0133]: use of mutable static is unsafe and requires unsafe function or block\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>  --> src\u002Fconfig\u002Fcfg.rs:35:5\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   |\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>35 |     count = count + 1;\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   |     ^^^^^^^^^^^^^^^^^ use of mutable static\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   |\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>   = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>For more information about this error, try `rustc --explain E0133`.\n\u003C\u002Fspan>\u003C\u002Fspan>\u003Cspan style=\"display:flex;\">\u003Cspan>error: could not compile `las` (bin "las") due to 2 previous errors\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fpre>\n\n\u003Cp>一定要修改的话，需要加\u003Ccode class=\"inline-code\">unsafe\u003C\u002Fcode>块包裹住：\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:#ff7b72\">mut\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>count: \u003Cspan style=\"color:#ff7b72\">usize\u003C\u002Fspan> \u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#a5d6ff\">0\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:#ff7b72\">pub\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">fn\u003C\u002Fspan> \u003Cspan style=\"color:#d2a8ff;font-weight:bold\">init_config\u003C\u002Fspan>(file_path: \u003Cspan style=\"color:#79c0ff\">&\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">str\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\">unsafe\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>{\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>count\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">=\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>count\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">+\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#a5d6ff\">1\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\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fpre>\n\n\u003Cp>但是，在rust中使用\u003Ccode class=\"inline-code\">unsafe\u003C\u002Fcode>是一件不好的事情，我们应该尽量避免使用\u003Ccode class=\"inline-code\">unsafe\u003C\u002Fcode>，这里有另一个方案可以实现在运行时设置全局变量，就是使用\u003Ccode class=\"inline-code\">once_cell\u003C\u002Fcode>这个包，虽然它的底层也是基于\u003Ccode class=\"inline-code\">unsafe\u003C\u002Fcode>来实现的，但是它对“不安全”代码进行了一定的包装。具体用法如下：\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\">CFG\u003C\u002Fspan>: \u003Cspan style=\"color:#f0883e;font-weight:bold\">OnceCell\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\"><\u003C\u002Fspan>Conf\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>OnceCell::new();\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 初始化和设置\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\">pub\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">fn\u003C\u002Fspan> \u003Cspan style=\"color:#d2a8ff;font-weight:bold\">init_config\u003C\u002Fspan>(file_path: \u003Cspan style=\"color:#79c0ff\">&\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">str\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:#79c0ff;font-weight:bold\">CFG\u003C\u002Fspan>.get_or_init(\u003Cspan style=\"color:#ff7b72;font-weight:bold\">|\u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72;font-weight:bold\">|\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>load_config(file_path));\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\">pub\u003C\u002Fspan>\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>\u003Cspan style=\"color:#ff7b72\">fn\u003C\u002Fspan> \u003Cspan style=\"color:#d2a8ff;font-weight:bold\">get_config\u003C\u002Fspan>()\u003Cspan style=\"color:#6e7681\"> \u003C\u002Fspan>-> \u003Cspan style=\"color:#79c0ff\">&\u003C\u002Fspan>'static \u003Cspan style=\"color:#f0883e;font-weight:bold\">Conf\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:#79c0ff;font-weight:bold\">CFG\u003C\u002Fspan>.get().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\">\n\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fpre>\n\n\u003Cp>可以看到，我们可以在运行时使用\u003Ccode class=\"inline-code\">once_cell\u003C\u002Fcode>的\u003Ccode class=\"inline-code\">get_or_init\u003C\u002Fcode>方法对全局变量进行初始化设置，它还有\u003Ccode class=\"inline-code\">set\u003C\u002Fcode>方法也可以在运行时对全局变量进行设置，\u003Ccode class=\"inline-code\">get\u003C\u002Fcode>方法在运行时对全局变量进行读取。从而实现不直接使用\u003Ccode class=\"inline-code\">unsafe\u003C\u002Fcode>块，来操作全局变量。而且\u003Ccode class=\"inline-code\">once_cell\u003C\u002Fcode>使用的全局变量完全不必申明为可变(\u003Ccode class=\"inline-code\">mut\u003C\u002Fcode>)变量。\u003C\u002Fp>\n\n\u003Cp>我们可以通过追踪\u003Ccode class=\"inline-code\">once_cell::get_or_init\u003C\u002Fcode>方法，可以看到在\u003Ccode class=\"inline-code\">initialize\u003C\u002Fcode>方法中\u003Ccode class=\"inline-code\">unsafe\u003C\u002Fcode>块中，将\u003Ccode class=\"inline-code\">value\u003C\u002Fcode>设置给了\u003Ccode class=\"inline-code\">*slot\u003C\u002Fcode>。\u003C\u002Fp>\n\n\u003Cp>\u003Cimg src=\"https:\u002F\u002Fimage.duguying.net\u002F2023\u002F11\u002Fqby9tqm9.webp\" alt=\"qby9tqm9\" \u002F>\u003C\u002Fp>\n\n\u003Cp>可以看到，\u003Ccode class=\"inline-code\">once_cell\u003C\u002Fcode>对全局变量的操作进行了安全封装，因此，建议使用\u003Ccode class=\"inline-code\">once_cell\u003C\u002Fcode>进行全局变量的操作，而不是到处使用\u003Ccode class=\"inline-code\">unsafe\u003C\u002Fcode>块进行不安全的操作。\u003C\u002Fp>\n\n\u003Cp>\u003Cstrong>^注意\u003C\u002Fstrong>：实践证明，\u003Ccode class=\"inline-code\">OnceCell\u003C\u002Fcode>只能调用\u003Ccode class=\"inline-code\">set()\u003C\u002Fcode>对全局变量设置一次，后续再调用\u003Ccode class=\"inline-code\">set()\u003C\u002Fcode>就会报错。要反复读写甚至多线程中读写全局变量，应该使用\u003Ccode class=\"inline-code\">RwLock\u003C\u002Fcode>，详情参考新的文章\u003Ca href=\"https:\u002F\u002Fwww.duguying.net\u002Farticle\u002Fread-and-write-global-var-in-multi-thread-for-rust\">《初学rust，多线程中读写全局变量》\u003C\u002Fa>\u003C\u002Fp>\n",{"title":28,"list":29},"最热文章",[30,36,42,48,54,60,66,72,78,84],{"id":31,"title":32,"uri":33,"author":10,"created_at":34,"view_count":35},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":37,"title":38,"uri":39,"author":10,"created_at":40,"view_count":41},21,"beego中使用fis","\u002Farticle\u002Fbeego中使用fis","2014-12-03 10:47:56",9250,{"id":43,"title":44,"uri":45,"author":10,"created_at":46,"view_count":47},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":49,"title":50,"uri":51,"author":10,"created_at":52,"view_count":53},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":55,"title":56,"uri":57,"author":10,"created_at":58,"view_count":59},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":61,"title":62,"uri":63,"author":10,"created_at":64,"view_count":65},19,"texlive中文书签乱码","\u002Farticle\u002Ftexlive中文书签乱码","2014-11-15 02:54:01",8461,{"id":67,"title":68,"uri":69,"author":10,"created_at":70,"view_count":71},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":73,"title":74,"uri":75,"author":10,"created_at":76,"view_count":77},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":79,"title":80,"uri":81,"author":10,"created_at":82,"view_count":83},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":85,"title":86,"uri":87,"author":10,"created_at":88,"view_count":89},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 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