{"id":66419,"date":"2023-12-19T03:45:05","date_gmt":"2023-12-18T19:45:05","guid":{"rendered":"https:\/\/docs.pingcode.com\/?p=66419"},"modified":"2023-12-19T03:45:08","modified_gmt":"2023-12-18T19:45:08","slug":"%e6%9c%80%e7%9f%ad%e7%9a%84%e5%8f%af%e4%bb%a5%e9%80%a0%e6%88%90%e5%b4%a9%e6%ba%83%e4%b8%94%e7%bc%96%e8%af%91%e5%99%a8%e6%97%a0%e6%b3%95%e4%bc%98%e5%8c%96%e6%8e%89%e7%9a%84-c%e4%bb%a3%e7%a0%81%e6%98%af","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/66419.html","title":{"rendered":"\u6700\u77ed\u7684\u53ef\u4ee5\u9020\u6210\u5d29\u6e83\u4e14\u7f16\u8bd1\u5668\u65e0\u6cd5\u4f18\u5316\u6389\u7684 C\u4ee3\u7801\u662f\u4ec0\u4e48"},"content":{"rendered":"\n<blockquote class=\"wp-block-quote\">\n<p><span>\u5728C\u8bed\u8a00\u4e2d\uff0c\u7f16\u5199\u80fd\u591f\u9020\u6210\u5d29\u6e83\u4e14\u96be\u4ee5\u88ab\u7f16\u8bd1\u5668\u4f18\u5316\u6389\u7684\u4ee3\u7801\u901a\u5e38\u6d89\u53ca\u5230\u672a\u5b9a\u4e49\u7684\u884c\u4e3a\uff08undefined behavior\uff09\u6216\u8005\u5bf9\u5e95\u5c42\u5185\u5b58\u7684\u975e\u6cd5\u64cd\u4f5c\u3002<\/span>\u5e94\u5f53\u6ce8\u610f\u7684\u662f\uff0c\u672a\u5b9a\u4e49\u7684\u884c\u4e3a\u662fC\u548cC++\u4e2d\u5e94\u8be5\u907f\u514d\u7684\uff0c\u56e0\u4e3a\u5b83\u4f7f\u5f97\u7a0b\u5e8f\u7684\u884c\u4e3a\u65e0\u6cd5\u9884\u6d4b\uff0c\u53ef\u80fd\u5bfc\u81f4\u4e0d\u540c\u7f16\u8bd1\u5668\u6216\u4e0d\u540c\u5e73\u53f0\u4e0a\u4ea7\u751f\u4e0d\u540c\u7684\u7ed3\u679c\u3002<\/p>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e00\u3001\u6700\u77ed\u7684\u53ef\u4ee5\u9020\u6210\u5d29\u6e83\u4e14\u7f16\u8bd1\u5668\u65e0\u6cd5\u4f18\u5316\u6389\u7684 C\u4ee3\u7801<\/h2>\n\n\n\n<p>\u5728C\u8bed\u8a00\u4e2d\uff0c\u7f16\u5199\u80fd\u591f\u9020\u6210\u5d29\u6e83\u4e14\u96be\u4ee5\u88ab\u7f16\u8bd1\u5668\u4f18\u5316\u6389\u7684\u4ee3\u7801\u901a\u5e38\u6d89\u53ca\u5230\u672a\u5b9a\u4e49\u7684\u884c\u4e3a\uff08undefined behavior\uff09\u6216\u8005\u5bf9\u5e95\u5c42\u5185\u5b58\u7684\u975e\u6cd5\u64cd\u4f5c\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u53ef\u80fd\u5bfc\u81f4\u5d29\u6e83\u5e76\u96be\u4ee5\u88ab\u4f18\u5316\u6389\u7684\u7b80\u77edC\u4ee3\u7801\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#include &lt;stdio.h&gt;\n\nint m<a href=\"https:\/\/docs.pingcode.com\/blog\/59162.html\" target=\"_blank\">AI<\/a>n() {\n    int *ptr = NULL;\n    *ptr = 42; \/\/ \u5bf9\u7a7a\u6307\u9488\u8fdb\u884c\u89e3\u5f15\u7528\n    return 0;\n}<\/code><\/pre>\n\n\n\n<p>\u8fd9\u6bb5\u4ee3\u7801\u9996\u5148\u5c06\u4e00\u4e2a\u7a7a\u6307\u9488 <code>ptr<\/code> \u521d\u59cb\u5316\u4e3a <code>NULL<\/code>\uff0c\u7136\u540e\u5c1d\u8bd5\u5bf9\u7a7a\u6307\u9488\u8fdb\u884c\u89e3\u5f15\u7528\u5e76\u8d4b\u503c\u3002\u8fd9\u662f\u4e00\u79cd\u672a\u5b9a\u4e49\u7684\u884c\u4e3a\uff0c\u56e0\u4e3a\u89e3\u5f15\u7528\u7a7a\u6307\u9488\u662f\u975e\u6cd5\u7684\u3002\u5728\u5b9e\u9645\u8fd0\u884c\u4e2d\uff0c\u8fd9\u53ef\u80fd\u5bfc\u81f4\u7a0b\u5e8f\u5d29\u6e83\uff0c\u56e0\u4e3a\u5b83\u8bd5\u56fe\u8bbf\u95ee\u4e0d\u5c5e\u4e8e\u5b83\u7684\u5185\u5b58\u3002<\/p>\n\n\n\n<p>\u8bf7\u6ce8\u610f\uff0c\u672a\u5b9a\u4e49\u7684\u884c\u4e3a\u662fC\u548cC++\u4e2d\u5e94\u8be5\u907f\u514d\u7684\uff0c\u56e0\u4e3a\u5b83\u4f7f\u5f97\u7a0b\u5e8f\u7684\u884c\u4e3a\u65e0\u6cd5\u9884\u6d4b\uff0c\u53ef\u80fd\u5bfc\u81f4\u4e0d\u540c\u7f16\u8bd1\u5668\u6216\u4e0d\u540c\u5e73\u53f0\u4e0a\u4ea7\u751f\u4e0d\u540c\u7684\u7ed3\u679c\u3002\u5728\u5b9e\u9645\u7684\u8f6f\u4ef6\u5f00\u53d1\u4e2d\uff0c\u7f16\u5199\u5065\u58ee\u4e14\u53ef\u9884\u6d4b\u7684\u4ee3\u7801\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e8c\u3001\u539f\u56e0<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u7a7a\u6307\u9488\u89e3\u5f15\u7528<\/h3>\n\n\n\n<p>\u5728\u63d0\u4f9b\u7684C\u4ee3\u7801\u4e2d\uff0c\u5c06\u4e00\u4e2a\u6307\u9488 <code>ptr<\/code> \u521d\u59cb\u5316\u4e3a <code>NULL<\/code>\uff0c\u5e76\u5c1d\u8bd5\u5bf9\u5176\u8fdb\u884c\u89e3\u5f15\u7528\uff0c\u5373\u901a\u8fc7 <code>*ptr<\/code> \u7684\u65b9\u5f0f\u8bbf\u95ee\u5176\u6307\u5411\u7684\u5185\u5b58\u3002\u8fd9\u662f\u4e00\u79cd\u672a\u5b9a\u4e49\u884c\u4e3a\uff0c\u56e0\u4e3a\u7a7a\u6307\u9488\u5e76\u4e0d\u6307\u5411\u6709\u6548\u7684\u5185\u5b58\u5730\u5740\u3002\u672a\u5b9a\u4e49\u7684\u884c\u4e3a\u610f\u5473\u7740\u7f16\u7a0b\u8bed\u8a00\u6807\u51c6\u6ca1\u6709\u89c4\u5b9a\u5bf9\u6b64\u7c7b\u64cd\u4f5c\u5e94\u8be5\u4ea7\u751f\u4f55\u79cd\u7ed3\u679c\uff0c\u56e0\u6b64\u7a0b\u5e8f\u7684\u884c\u4e3a\u662f\u4e0d\u786e\u5b9a\u7684\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u5199\u5165\u975e\u6cd5\u5185\u5b58<\/h3>\n\n\n\n<p>\u901a\u8fc7 <code>*ptr = 42;<\/code> \u7684\u64cd\u4f5c\uff0c\u8bd5\u56fe\u5c06\u503c42\u5199\u5165\u7a7a\u6307\u9488\u6240\u6307\u5411\u7684\u5185\u5b58\u5730\u5740\u3002\u7531\u4e8e\u6307\u9488\u88ab\u521d\u59cb\u5316\u4e3aNULL\uff0c\u8fd9\u5b9e\u9645\u4e0a\u662f\u5bf9\u975e\u6cd5\u5185\u5b58\u7684\u5199\u5165\u3002\u8fd9\u79cd\u884c\u4e3a\u53ef\u80fd\u5bfc\u81f4\u5185\u5b58\u7834\u574f\uff0c\u56e0\u4e3a\u7a0b\u5e8f\u8bd5\u56fe\u5728\u672a\u88ab\u5206\u914d\u7684\u5185\u5b58\u533a\u57df\u4e2d\u5199\u5165\u6570\u636e\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u672a\u5b9a\u4e49\u7684\u884c\u4e3a<\/h3>\n\n\n\n<p>\u5728C\u8bed\u8a00\u4e2d\uff0c\u5bf9\u7a7a\u6307\u9488\u8fdb\u884c\u89e3\u5f15\u7528\u662f\u4e00\u79cd\u672a\u5b9a\u4e49\u884c\u4e3a\u3002\u7f16\u7a0b\u8bed\u8a00\u6807\u51c6\u6ca1\u6709\u5b9a\u4e49\u8fd9\u79cd\u64cd\u4f5c\u7684\u5177\u4f53\u7ed3\u679c\uff0c\u56e0\u6b64\u7a0b\u5e8f\u53ef\u80fd\u5728\u4e0d\u540c\u7684\u7f16\u8bd1\u5668\u548c\u5e73\u53f0\u4e0a\u8868\u73b0\u51fa\u4e0d\u540c\u7684\u884c\u4e3a\u3002\u8fd9\u589e\u52a0\u4e86\u4ee3\u7801\u7684\u4e0d\u786e\u5b9a\u6027\u548c\u4e0d\u53ef\u79fb\u690d\u6027\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. \u7f16\u8bd1\u5668\u65e0\u6cd5\u4f18\u5316<\/h3>\n\n\n\n<p>\u5b58\u5728\u672a\u5b9a\u4e49\u884c\u4e3a\u7684\u4ee3\u7801\u901a\u5e38\u4f1a\u963b\u6b62\u7f16\u8bd1\u5668\u8fdb\u884c\u4e00\u4e9b\u4f18\u5316\uff0c\u56e0\u4e3a\u7f16\u8bd1\u5668\u65e0\u6cd5\u51c6\u786e\u9884\u6d4b\u4ee3\u7801\u7684\u884c\u4e3a\u3002\u4f18\u5316\u901a\u5e38\u57fa\u4e8e\u5bf9\u4ee3\u7801\u884c\u4e3a\u7684\u9759\u6001\u5206\u6790\uff0c\u4f46\u7531\u4e8e\u672a\u5b9a\u4e49\u884c\u4e3a\u7684\u5b58\u5728\uff0c\u7f16\u8bd1\u5668\u65e0\u6cd5\u8fdb\u884c\u6709\u6548\u7684\u4f18\u5316\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5. \u53ef\u80fd\u5bfc\u81f4\u5d29\u6e83<\/h3>\n\n\n\n<p>\u7531\u4e8e\u5bf9\u7a7a\u6307\u9488\u8fdb\u884c\u89e3\u5f15\u7528\uff0c\u7a0b\u5e8f\u53ef\u80fd\u4f1a\u5bfc\u81f4\u5d29\u6e83\u3002\u5728\u5b9e\u9645\u8fd0\u884c\u4e2d\uff0c\u8fd9\u53ef\u80fd\u8868\u73b0\u4e3a\u64cd\u4f5c\u7cfb\u7edf\u53d1\u51fa\u7684\u6bb5\u9519\u8bef\u6216\u8bbf\u95ee\u51b2\u7a81\uff0c\u4f7f\u7a0b\u5e8f\u5f02\u5e38\u7ec8\u6b62\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6. \u7f16\u5199\u5065\u58ee\u4ee3\u7801\u7684\u53cd\u4f8b<\/h3>\n\n\n\n<p>\u8fd9\u6bb5\u4ee3\u7801\u662f\u7f16\u5199\u5065\u58ee\u3001\u53ef\u7ef4\u62a4\u548c\u53ef\u9760\u4ee3\u7801\u7684\u53cd\u4f8b\u3002\u826f\u597d\u7684\u7f16\u7801\u5b9e\u8df5\u5e94\u8be5\u907f\u514d\u672a\u5b9a\u4e49\u884c\u4e3a\uff0c\u786e\u4fdd\u4ee3\u7801\u5728\u5404\u79cd\u6761\u4ef6\u4e0b\u90fd\u80fd\u591f\u7a33\u5b9a\u8fd0\u884c\u3002\u5bf9\u4e8e\u6307\u9488\u7684\u4f7f\u7528\uff0c\u59cb\u7ec8\u8981\u786e\u4fdd\u6307\u9488\u5728\u89e3\u5f15\u7528\u4e4b\u524d\u5df2\u7ecf\u88ab\u6b63\u786e\u521d\u59cb\u5316\uff0c\u4ee5\u9632\u6b62\u7c7b\u4f3c\u4e8e\u7a7a\u6307\u9488\u89e3\u5f15\u7528\u8fd9\u6837\u7684\u5371\u9669\u64cd\u4f5c\u3002<\/p>\n\n\n\n<p><img fetchpriority=\"high\" decoding=\"async\" width=\"484\" height=\"300\" src=\"https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/12\/412304-\u6700\u77ed\u7684\u53ef\u4ee5\u9020\u6210\u5d29\u6e83\u4e14\u7f16\u8bd1\u5668\u65e0\u6cd5\u4f18\u5316\u6389\u7684C\u4ee3\u7801\u662f\u4ec0\u4e48.png?x-oss-process=image\/auto-orient,1\/format,webp\" class=\"aligncenter\" alt=\"\u6700\u77ed\u7684\u53ef\u4ee5\u9020\u6210\u5d29\u6e83\u4e14\u7f16\u8bd1\u5668\u65e0\u6cd5\u4f18\u5316\u6389\u7684 C\u4ee3\u7801\u662f\u4ec0\u4e48\" \/><\/p>\n\n\n\n<p><strong>\u5e38\u89c1\u95ee\u7b54\uff1a<\/strong><\/p>\n\n\n\n<ul>\n<li>\u95ee\uff1a\u4e3a\u4ec0\u4e48\u7f16\u8bd1\u5668\u65e0\u6cd5\u4f18\u5316\u5e26\u6709 <code>volatile<\/code> \u5173\u952e\u5b57\u7684\u53d8\u91cf\uff1f<\/li>\n\n\n\n<li>\u7b54\uff1a<code>volatile<\/code> \u5173\u952e\u5b57\u544a\u8bc9\u7f16\u8bd1\u5668\u8be5\u53d8\u91cf\u7684\u503c\u53ef\u80fd\u4f1a\u5728\u5916\u90e8\u88ab\u4fee\u6539\uff0c\u56e0\u6b64\u7f16\u8bd1\u5668\u65e0\u6cd5\u5bf9\u5176\u8fdb\u884c\u5e38\u89c4\u7684\u4f18\u5316\uff0c\u4ee5\u786e\u4fdd\u5bf9\u8be5\u53d8\u91cf\u7684\u6bcf\u6b21\u8bfb\u53d6\u548c\u5199\u5165\u90fd\u80fd\u53ca\u65f6\u53cd\u6620\u5916\u90e8\u7684\u53d8\u5316\u3002<\/li>\n<\/ul>\n\n\n\n<ul>\n<li>\u95ee\uff1a\u4e3a\u4ec0\u4e48\u5305\u542b\u51fd\u6570\u6307\u9488\u7684\u4ee3\u7801\u96be\u4ee5\u88ab\u7f16\u8bd1\u5668\u4f18\u5316\uff1f<\/li>\n\n\n\n<li>\u7b54\uff1a\u51fd\u6570\u6307\u9488\u7684\u4f7f\u7528\u4f7f\u5f97\u7f16\u8bd1\u5668\u5728\u7f16\u8bd1\u65f6\u96be\u4ee5\u786e\u5b9a\u5177\u4f53\u8c03\u7528\u7684\u51fd\u6570\uff0c\u56e0\u6b64\u5728\u5305\u542b\u51fd\u6570\u6307\u9488\u7684\u4ee3\u7801\u4e2d\uff0c\u7f16\u8bd1\u5668\u53ef\u80fd\u65e0\u6cd5\u8fdb\u884c\u67d0\u4e9b\u4f18\u5316\uff0c\u5982\u5185\u8054\u51fd\u6570\u7b49\uff0c\u4ee5\u786e\u4fdd\u6b63\u786e\u7684\u52a8\u6001\u8c03\u7528\u3002<\/li>\n<\/ul>\n\n\n\n<ul>\n<li>\u95ee\uff1a\u590d\u6742\u7684\u63a7\u5236\u6d41\u7ed3\u6784\u4e3a\u4ec0\u4e48\u4f7f\u5f97\u7f16\u8bd1\u5668\u96be\u4ee5\u8fdb\u884c\u5168\u5c40\u4f18\u5316\uff1f<\/li>\n\n\n\n<li>\u7b54\uff1a\u590d\u6742\u7684\u63a7\u5236\u6d41\u7ed3\u6784\uff0c\u5982\u5927\u91cf\u7684\u6761\u4ef6\u5206\u652f\u3001\u5faa\u73af\u5d4c\u5957\u7b49\uff0c\u4f7f\u5f97\u7f16\u8bd1\u5668\u5728\u5168\u5c40\u8303\u56f4\u5185\u96be\u4ee5\u8fdb\u884c\u51c6\u786e\u7684\u63a7\u5236\u6d41\u5206\u6790\u548c\u4f18\u5316\uff0c\u56e0\u6b64\u53ef\u80fd\u65e0\u6cd5\u5bf9\u6574\u4e2a\u4ee3\u7801\u8fdb\u884c\u6709\u6548\u7684\u6027\u80fd\u4f18\u5316\u3002<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"\u5728C\u8bed\u8a00\u4e2d\uff0c\u7f16\u5199\u80fd\u591f\u9020\u6210\u5d29\u6e83\u4e14\u96be\u4ee5\u88ab\u7f16\u8bd1\u5668\u4f18\u5316\u6389\u7684\u4ee3\u7801\u901a\u5e38\u6d89\u53ca\u5230\u672a\u5b9a\u4e49\u7684\u884c\u4e3a\uff08undefined behavi [&hellip;]","protected":false},"author":4,"featured_media":66422,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[3472,960],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/66419"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=66419"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/66419\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/66422"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=66419"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=66419"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=66419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}