{"id":302,"date":"2022-06-30T14:09:52","date_gmt":"2022-06-30T06:09:52","guid":{"rendered":"https:\/\/www.fengjijiao.cn\/?p=302"},"modified":"2022-06-30T14:09:52","modified_gmt":"2022-06-30T06:09:52","slug":"c%e4%b8%8d%e5%ae%89%e5%85%a8%e4%bb%a3%e7%a0%81%ef%bc%88unsafe%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.fengjijiao.cn\/?p=302","title":{"rendered":"C#\u4e0d\u5b89\u5168\u4ee3\u7801\uff08unsafe\uff09"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code>using System;\r\n\r\nnamespace ConsoleApp1\r\n{\r\n    class Program\r\n    {\r\n        static void Main(string&#91;] args)\r\n        {\r\n            \/\/C#\u4e0d\u5b89\u5168\u4ee3\u7801\r\n            \/*\r\n             * \u5f53\u4e00\u4e2a\u4ee3\u7801\u5757\u4f7f\u7528unsafe\u4fee\u9970\u7b26\u6807\u8bb0\u65f6\uff0cC#\u5141\u8bb8\u5728\u51fd\u6570\u4e2d\u4f7f\u7528\u6307\u9488\u53d8\u91cf\u3002\u4e0d\u5b89\u5168\u4ee3\u7801\u6216\u975e\u6258\u7ba1\u4ee3\u7801\u662f\u6307\u4f7f\u7528\u4e86\u6307\u9488\u53d8\u91cf\u7684\u4ee3\u7801\u5757\u3002\r\n             * \r\n             * \u6307\u9488\u53d8\u91cf\r\n             * \u6307\u9488\u662f\u503c\u4e3a\u53e6\u4e00\u4e2a\u53d8\u91cf\u7684\u5730\u5740\u7684\u53d8\u91cf\uff0c\u5373\uff0c\u5185\u5b58\u4f4d\u7f6e\u7684\u76f4\u63a5\u5730\u5740\u3002\u5c31\u50cf\u5176\u4ed6\u53d8\u91cf\u6216\u5e38\u91cf\uff0c\u4f60\u5fc5\u987b\u5728\u4f7f\u7528\u6307\u9488\u5b58\u50a8\u5176\u4ed6\u53d8\u91cf\u5730\u5740\u4e4b\u524d\u58f0\u660e\u6307\u9488\u3002\r\n             * type* var name;\r\n             * \r\n             * int* p           p\u662f\u6307\u5411\u6574\u6570\u7684\u6307\u9488\r\n             * double* p        p\u662f\u6307\u5411\u53cc\u7cbe\u5ea6\u6570\u7684\u6307\u9488\r\n             * float* p         p\u662f\u6307\u5411\u6d6e\u70b9\u6570\u7684\u6307\u9488\r\n             * int** p          p\u662f\u6307\u5411\u6574\u6570\u7684\u6307\u9488\u7684\u6307\u9488\r\n             * int*&#91;] p         p\u662f\u6307\u5411\u6574\u6570\u7684\u6307\u9488\u7684\u4e00\u7ef4\u6570\u7ec4\r\n             * char* p          p\u662f\u6307\u5411\u5b57\u7b26\u7684\u6307\u9488\r\n             * void* p          p\u662f\u6307\u5411\u672a\u77e5\u7c7b\u578b\u7684\u6307\u9488\r\n             * \r\n             * \u5728\u540c\u4e00\u4e2a\u58f0\u660e\u4e2d\u58f0\u660e\u591a\u4e2a\u6307\u9488\uff1a\r\n             * int* p1,p2,p3;\r\n             *\/\r\n             unsafe\/\/\u6216\u5728Main\u65b9\u6cd5\u4e0a\u7684void\u524d\u6dfb\u52a0unsafe\u5173\u952e\u5b57\r\n            {\r\n                int var = 20;\r\n                int* p = &amp;var;\r\n                Console.WriteLine(\"Data is: {0}\", var);\r\n                Console.WriteLine(\"Address is: {0}\", (int)p);\r\n            }\r\n\r\n            \/\/\u4f20\u9012\u6307\u9488\u4f5c\u4e3a\u65b9\u6cd5\u7684\u53c2\u6570\r\n            unsafe\r\n            {\r\n                TestPointer tp = new TestPointer();\r\n                int var1 = 10;\r\n                int var2 = 20;\r\n                int* x = &amp;var1;\r\n                int* y = &amp;var2;\r\n                Console.WriteLine(\"before: var1: {0}, var2: {1}\", var1, var2);\r\n                tp.swap(x, y);\r\n                Console.WriteLine(\"after: var1: {0}, var2: {1}\", var1, var2);\r\n            }\r\n            \r\n            \/\/\u4f7f\u7528\u6307\u9488\u8bbf\u95ee\u6570\u7ec4\u5143\u7d20\r\n            \/*\r\n             * \u5728C#\u4e2d\uff0c\u6570\u7ec4\u540d\u79f0\u548c\u4e00\u4e2a\u6307\u5411\u4e0e\u6570\u7ec4\u6570\u636e\u5177\u6709\u76f8\u540c\u6570\u636e\u7c7b\u578b\u7684\u6307\u9488\u662f\u4e0d\u540c\u7684\u53d8\u91cf\u7c7b\u578b\u3002\r\n             * \u4f8b\u5982\uff0cint *p\u548cint&#91;] p\u662f\u4e0d\u540c\u7684\u7c7b\u578b\u3002\u4f60\u53ef\u4ee5\u589e\u52a0\u6307\u9488\u53d8\u91cfp\uff0c\u56e0\u4e3a\u5b83\u5728\u5185\u5b58\u4e2d\u662f\u4e0d\u56fa\u5b9a\u7684\uff0c\u4f46\u662f\u6570\u7ec4\u5730\u5740\u5728\u5185\u5b58\u4e2d\u662f\u56fa\u5b9a\u7684\uff0c\u6240\u4ee5\u4f60\u4e0d\u80fd\u589e\u52a0\u6570\u7ec4p\u3002\r\n             * \u56e0\u6b64\uff0c\u5982\u679c\u4f60\u9700\u8981\u4f7f\u7528\u6307\u9488\u53d8\u91cf\u8bbf\u95ee\u6570\u7ec4\u6570\u636e\uff0c\u53ef\u4ee5\u50cf\u6211\u4eec\u901a\u5e38\u5728C\/C++\u4e2d\u6240\u505a\u7684\u90a3\u6837\uff0c\u4f7f\u7528fixed\u5173\u952e\u5b57\u6765\u56fa\u5b9a\u6307\u9488\u3002\r\n             *\/\r\n             \/\/\u5b9e\u4f8b\r\n             unsafe\r\n            {\r\n                int&#91;] list = {10,100,200 };\r\n                fixed (int *ptr = list)\r\n                    \/*\r\n                     * \u5728C#\u4e2d\u58f0\u660e\u7684\u53d8\u91cf\u5728\u5185\u5b58\u4e2d\u7684\u5b58\u50a8\u53d7\u5783\u573e\u56de\u6536\u5668\u7684\u7ba1\u7406\uff1b\u56e0\u6b64\u4e00\u4e2a\u53d8\u91cf\uff08\u4f8b\u5982\u4e00\u4e2a\u5927\u6570\u7ec4\uff09\u6709\u53ef\u80fd\u5728\u8fd0\u884c\u8fc7\u7a0b\u4e2d\u88ab\u79fb\u52a8\u5230\u5185\u5b58\u4e2d\u5176\u4ed6\u4f4d\u7f6e\u3002\u5982\u679c\u4e00\u4e2a\u53d8\u91cf\u7684\u5185\u5b58\u5730\u5740\u4f1a\u53d8\u5316\uff0c\u90a3\u4e48\u6307\u9488\u4e5f\u5c31\u6ca1\u6709\u610f\u4e49\u4e86\u3002\r\n                     * \u89e3\u51b3\u65b9\u6cd5\u662f\u4f7f\u7528fixed\u5173\u952e\u5b57\u6765\u56fa\u5b9a\u53d8\u91cf\u4f4d\u7f6e\u4e0d\u79fb\u52a8\u3002\r\n                     * \r\n                     * \u5728unsafe\u4e0d\u5b89\u5168\u73af\u5883\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7stackalloc\u5728\u5806\u6808\u4e0a\u5206\u914d\u5185\u5b58\uff0c\u56e0\u4e3a\u5728\u5806\u6808\u4e0a\u5206\u914d\u7684\u5185\u5b58\u4e0d\u53d7\u5185\u5b58\u7ba1\u7406\u5668\u7ba1\u7406\uff0c\u56e0\u6b64\u5176\u76f8\u5e94\u7684\u6307\u9488\u4e0d\u9700\u8981\u56fa\u5b9a\u3002\r\n                     * static unsafe void Main(string&#91;] args)\r\n                     * {\r\n                     *     int *ptr = stackalloc int&#91;1];\r\n                     * }\r\n                     *\/\r\n\r\n                \/*\u663e\u793a\u6307\u9488\u4e2d\u6570\u7ec4\u5730\u5740*\/\r\n                for(int i = 0;i&lt;3;i++)\r\n                {\r\n                    Console.WriteLine(\"Address of list&#91;{0}] = {1}\", i, (int)(ptr+i));\r\n                    Console.WriteLine(\"Value of list&#91;{0}] = {1}\", i, *(ptr+i));\r\n                }\r\n            }\r\n            Console.ReadKey();\r\n        }\r\n    }\r\n    public class TestPointer\r\n    {\r\n        public unsafe void swap(int* p, int* q)\r\n        {\r\n            int temp = *p;\r\n            *p = *q;\r\n            *q = temp;\r\n        }\r\n    }\r\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[19],"tags":[],"_links":{"self":[{"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=\/wp\/v2\/posts\/302"}],"collection":[{"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=302"}],"version-history":[{"count":1,"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=\/wp\/v2\/posts\/302\/revisions"}],"predecessor-version":[{"id":303,"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=\/wp\/v2\/posts\/302\/revisions\/303"}],"wp:attachment":[{"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=302"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=302"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fengjijiao.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=302"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}