{"id":800,"date":"2021-12-18T17:13:53","date_gmt":"2021-12-18T09:13:53","guid":{"rendered":"https:\/\/blog.cauchyschwarz.com\/?p=800"},"modified":"2021-12-18T17:13:59","modified_gmt":"2021-12-18T09:13:59","slug":"c%e5%86%85%e5%ad%98%e5%af%b9%e9%bd%90","status":"publish","type":"post","link":"https:\/\/blog.cauchyschwarz.com\/?p=800","title":{"rendered":"C++\u5185\u5b58\u5bf9\u9f50"},"content":{"rendered":"\n<p>\u8bb0\u5f55\u4e0b\u6700\u8fd1\u5de5\u4f5c\u4e2d\u9047\u5230\u7684\u5751\uff0c\u5176\u4e2d\u4e4b\u4e00\u4fbf\u662fC\/C++\u91cc\u9762\u7684\u5185\u5b58\u5bf9\u9f50\u3002<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_82_2 ez-toc-wrap-right counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-69e0f4f942042\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span 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ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=800\/#%E4%B8%BA%E4%BB%80%E4%B9%88%E6%9C%89%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90\" >\u4e3a\u4ec0\u4e48\u6709\u5185\u5b58\u5bf9\u9f50<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=800\/#%E7%90%86%E8%A7%A3%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E8%AE%B2%E4%BA%86%E4%BB%80%E4%B9%88\" >\u7406\u89e3\u5185\u5b58\u5bf9\u9f50\u8bb2\u4e86\u4ec0\u4e48<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=800\/#%E7%BC%96%E7%A8%8B%E8%AF%AD%E8%A8%80%E4%B8%BA%E6%88%91%E4%BB%AC%E6%8F%90%E4%BE%9B%E4%BA%86%E5%85%B3%E4%BA%8E%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E7%9A%84%E5%93%AA%E4%BA%9B%E5%B7%A5%E5%85%B7\" >\u7f16\u7a0b\u8bed\u8a00\u4e3a\u6211\u4eec\u63d0\u4f9b\u4e86\u5173\u4e8e\u5185\u5b58\u5bf9\u9f50\u7684\u54ea\u4e9b\u5de5\u5177<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=800\/#%E8%B8%A9%E8%BF%87%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E7%9A%84%E5%93%AA%E4%BA%9B%E5%9D%91\" >\u8e29\u8fc7\u5185\u5b58\u5bf9\u9f50\u7684\u54ea\u4e9b\u5751<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=800\/#%E7%90%86%E8%A7%A3%E4%BA%86%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E5%90%8E%E5%8F%AF%E4%BB%A5%E6%80%8E%E6%A0%B7%E6%8A%8A%E7%A8%8B%E5%BA%8F%E5%86%99%E7%9A%84%E6%9B%B4%E5%A5%BD\" >\u7406\u89e3\u4e86\u5185\u5b58\u5bf9\u9f50\u540e\u53ef\u4ee5\u600e\u6837\u628a\u7a0b\u5e8f\u5199\u7684\u66f4\u597d<\/a><\/li><\/ul><\/nav><\/div>\n<h1 class=\"wp-block-heading\" id=\"%E4%B8%BA%E4%BB%80%E4%B9%88%E6%9C%89%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90\"><span class=\"ez-toc-section\" id=\"%E4%B8%BA%E4%BB%80%E4%B9%88%E6%9C%89%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90\"><\/span>\u4e3a\u4ec0\u4e48\u6709\u5185\u5b58\u5bf9\u9f50<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<ul class=\"wp-block-list\"><li>\u4e3a\u4e86\u6027\u80fd<ul><li>\u7531\u4e8e\u5185\u5b58\u786c\u4ef6\u4e0a\u7684\u7ec4\u7ec7\u65b9\u5f0f(\u5177\u4f53\u770b\u8fd9\u7bc7<a href=\"https:\/\/www.geeksforgeeks.org\/structure-member-alignment-padding-and-data-packing\/\">\u4ecb\u7ecd\u5185\u5b58\u5bf9\u9f50\u7684\u6587\u7ae0<\/a>)\uff0c\u4ece\u5185\u5b58\u4e2d\u8bfb\u53d6\u6570\u636e\u65f6\u5f80\u5f80\u662f\u4e00\u6b21\u6027\u8bfb\u53d64\u5b57\u8282\u30018\u5b57\u8282\uff0c\u4e3a\u4e86\u80fd\u591f\u5c3d\u53ef\u80fd\u5730\u63d0\u5347\u8bfb\u5199\u5185\u5b58\u7684\u6548\u7387\uff0c\u4e8e\u662f\u6709\u4e86\u5185\u5b58\u5bf9\u9f50\u7684\u6982\u5ff5\u3002<\/li><li>\u50cf\u4e00\u4e9bSSE\u4e4b\u7c7b\u7684\u6307\u4ee4\u5bf9\u6570\u636e\u4e5f\u6709\u7740\u5bf9\u9f50\u4e0a\u7684\u8981\u6c42\u3002<\/li><\/ul><\/li><li>CPU\u5bfb\u5740\u652f\u6301<br>\u6bd4\u5982\u5728\u67d0\u4e9b\u5e73\u53f0\u4e0a\u5982\u679c\u4f60\u628aint\u5b58\u653e\u5728\u4e0d\u662f4\u7684\u500d\u6570\u5f00\u5934\u7684\u5730\u5740\uff0c\u90a3\u4e48\u4f60\u53bb\u5b58\u53d6\u8fd9\u4e2aint\u7684\u65f6\u5019\u662f\u4f1a\u62a5Bus Error(SIGBUS)\u7684\u3002\u5199\u8fc7\u79fb\u52a8\u7aefsdk\u7684\u4eba\u5e94\u8be5\u5bf9\u6b64\u6df1\u6709\u4f53\u4f1a\u3002\u5728x86\u5e73\u53f0\u4e0a\u5219\u6ca1\u6709\u8fd9\u79cd\u95ee\u9898\u3002<\/li><\/ul>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"%E7%90%86%E8%A7%A3%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E8%AE%B2%E4%BA%86%E4%BB%80%E4%B9%88\"><span class=\"ez-toc-section\" id=\"%E7%90%86%E8%A7%A3%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E8%AE%B2%E4%BA%86%E4%BB%80%E4%B9%88\"><\/span>\u7406\u89e3\u5185\u5b58\u5bf9\u9f50\u8bb2\u4e86\u4ec0\u4e48<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p>\u5bf9\u4e8e\u57fa\u672c\u6570\u636e\u7c7b\u578b\uff0c\u8fd9\u4e9b\u6570\u636e\u7684\u5185\u5b58\u5730\u5740\u5fc5\u987b\u662f\u5176\u5bf9\u9f50\u957f\u5ea6\u7684\u500d\u6570\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Data Type<\/th><th>32-bit (bytes)<\/th><th>64-bit(bytes)<\/th><\/tr><\/thead><tbody><tr><td>char<\/td><td>1<\/td><td>1<\/td><\/tr><tr><td>short<\/td><td>2<\/td><td>2<\/td><\/tr><tr><td>int<\/td><td>4<\/td><td>4<\/td><\/tr><tr><td>long<\/td><td>8<\/td><td>8<\/td><\/tr><tr><td>float<\/td><td>4<\/td><td>4<\/td><\/tr><tr><td>double<\/td><td>8<\/td><td>8<\/td><\/tr><tr><td>long long<\/td><td>8<\/td><td>8<\/td><\/tr><tr><td>long double<\/td><td>4<\/td><td>16<\/td><\/tr><tr><td>Any pointer<\/td><td>4<\/td><td>8<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u5bf9\u4e8e\u7ed3\u6784\u4f53\uff0c\u5176\u5bf9\u9f50\u957f\u5ea6\u662f\u5176\u6210\u5458\u91cc\u5bf9\u9f50\u957f\u5ea6\u6700\u5927\u7684\u90a3\u4e00\u4e2a\uff1b<br>\u4e3a\u4e86\u7167\u987e\u5185\u5b58\u5bf9\u9f50\uff0c\u7ed3\u6784\u4f53\u7684\u5185\u90e8\u548c\u672b\u5c3e\u4f1a\u4ea7\u751fpadding\uff1b<br>\u6bd4\u5982<a href=\"https:\/\/software.intel.com\/en-us\/articles\/coding-for-performance-data-alignment-and-structures\">intel\u8fd9\u7bc7\u6587\u6863\u91cc\u7684\u4f8b\u5b50<\/a>\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"cpp\" class=\"language-cpp\">struct s1\n{\n  char a;\n  short a1;\n  char b1;\n  float b;\n  int c;\n  char e;\n  double f;\n};\nstruct s2\n{\n  double f;\n  float b;\n  short a1;\n  char a,b1,e;\n};\n<\/code><\/pre>\n\n\n\n<p>\u7ed3\u6784\u4f53s1\u8981\u5360\u752832\u4e2a\u5b57\u8282\uff0c\u5185\u90e8\u670911\u4e2a\u5b57\u8282\u7684padding\uff0c\u800c\u6210\u5458\u76f8\u540c\u7684\u7ed3\u6784\u4f53s2\u53ea\u5360\u752824\u4e2a\u5b57\u8282\uff0c\u53ea\u6709\u672b\u5c3e\u76843\u4e2a\u5b57\u8282\u7684padding\u3002<br>malloc\u51fd\u6570\u8fd4\u56de\u503c\u662f\u4e00\u4e2a\u6309\u7167<em>max_align_t<\/em>\u5bf9\u9f50\u7684\u5730\u5740\uff0c\u8fd9\u4e2a<em>max_align_t<\/em>\u4e00\u822c\u662f8\u548c16\uff0c\u6309<em>max_align_t<\/em>\u5bf9\u9f50\u4fdd\u8bc1\u4e86\u6240\u6709\u57fa\u672c\u6570\u636e\u7c7b\u578b\u90fd\u53ef\u4ee5\u653e\u5728malloc\u8fd4\u56de\u5730\u5740\u5f00\u5934\u7684\u5185\u5b58\u91cc\uff1b<\/p>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"%E7%BC%96%E7%A8%8B%E8%AF%AD%E8%A8%80%E4%B8%BA%E6%88%91%E4%BB%AC%E6%8F%90%E4%BE%9B%E4%BA%86%E5%85%B3%E4%BA%8E%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E7%9A%84%E5%93%AA%E4%BA%9B%E5%B7%A5%E5%85%B7\"><span class=\"ez-toc-section\" id=\"%E7%BC%96%E7%A8%8B%E8%AF%AD%E8%A8%80%E4%B8%BA%E6%88%91%E4%BB%AC%E6%8F%90%E4%BE%9B%E4%BA%86%E5%85%B3%E4%BA%8E%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E7%9A%84%E5%93%AA%E4%BA%9B%E5%B7%A5%E5%85%B7\"><\/span>\u7f16\u7a0b\u8bed\u8a00\u4e3a\u6211\u4eec\u63d0\u4f9b\u4e86\u5173\u4e8e\u5185\u5b58\u5bf9\u9f50\u7684\u54ea\u4e9b\u5de5\u5177<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"%E8%B8%A9%E8%BF%87%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E7%9A%84%E5%93%AA%E4%BA%9B%E5%9D%91\"><span class=\"ez-toc-section\" id=\"%E8%B8%A9%E8%BF%87%E5%86%85%E5%AD%98%E5%AF%B9%E9%BD%90%E7%9A%84%E5%93%AA%E4%BA%9B%E5%9D%91\"><\/span>\u8e29\u8fc7\u5185\u5b58\u5bf9\u9f50\u7684\u54ea\u4e9b\u5751<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<ul class=\"wp-block-list\"><li>\u5199\u79fb\u52a8\u7aefsdk\u7684\u4eba\u7ecf\u5e38\u4f1a\u9047\u5230\u6ca1\u6ce8\u610f\u5185\u5b58\u5bf9\u9f50\uff0c\u5bfc\u81f4\u62a5SIGBUS\u7684\u95ee\u9898\uff1b<br>\u4e3a\u4e86\u5199\u51fa\u66f4portable\u548c\u5065\u58ee\u7684\u4ee3\u7801\uff0c\u9700\u8981\u7559\u610f\u6570\u636e\u7c7b\u578b\u7684\u5bf9\u9f50\u8981\u6c42\uff1b<\/li><li>\u56e0\u4e3a\u5ffd\u7565\u4e86\u5185\u5b58\u5bf9\u9f50\u7684\u5f71\u54cd\uff0c\u5728\u624b\u52a8\u8ba1\u7b97\u7ed3\u6784\u4f53\u5927\u5c0f\u548c\u6210\u5458\u53d8\u91cf\u7684\u504f\u79fb\u91cf\u65f6\u7ecf\u5e38\u51fa\u9519\uff1b<br>\u8fd9\u79cd\u9519\u8bef\u633a\u5751\u7684\uff0c\u53ef\u80fd\u4f60\u672c\u610f\u662f\u6253\u7b97\u5b58\u53d6\u67d0\u4e2a\u6210\u5458\u53d8\u91cf\u7684\uff0c\u5b9e\u9645\u4e0a\u5374\u64cd\u4f5c\u7684\u662f\u4f5c\u4e3apadding\u7684\u65e0\u7528\u6570\u636e\uff0c\u5728\u5e8f\u5217\u5316\u53cd\u5e8f\u5217\u5316\u4f20\u9012\u6570\u636e\u65f6\u5c31\u4f1a\u9047\u5230\u8fd9\u79cd\u5751\uff1b<br>\u89e3\u51b3\u529e\u6cd5\u5c31\u662f\u8981\u4e48\u7262\u8bb0\u5185\u5b58\u5bf9\u9f50\u7684\u89c4\u5219\uff0c\u8981\u4e48\u8bf7\u719f\u7ec3\u4f7f\u7528sizeof\u548coffsetof\u4e24\u4e2a\u5b8f\uff1b<\/li><\/ul>\n\n\n\n<h1 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