{"id":1756,"date":"2010-10-14T22:00:52","date_gmt":"2010-10-14T14:00:52","guid":{"rendered":"http:\/\/edsionte.com\/techblog\/?p=1756"},"modified":"2010-11-27T23:32:23","modified_gmt":"2010-11-27T15:32:23","slug":"constenum","status":"publish","type":"post","link":"http:\/\/edsionte.com\/techblog\/archives\/1756","title":{"rendered":"const\u548cenum"},"content":{"rendered":"<h4><strong><em>const<\/em><\/strong><\/h4>\n<p>\u6211\u4eec\u53ef\u4ee5\u5c06const\u5173\u952e\u5b57\u6240\u4fee\u9970\u7684\u53d8\u91cf\u770b\u4f5c\u662f\u53ea\u8bfb\u53d8\u91cf\uff0c\u4e5f\u5c31\u662f\u8bf4\u8fd9\u4e2a\u53d8\u91cf\u4e0d\u53ef\u88ab\u4fee\u6539\uff0c\u53ea\u80fd\u8bfb\u53d6\u5176\u503c\u3002\u4f46\u5b83\u51b3\u4e0d\u662f\u5e38\u91cf\u3002\u5728\u6807\u51c6C\u8bed\u8a00\u4e2d\uff0c\u4e0b\u9762\u7684\u8bed\u53e5\u662f\u9519\u8bef\u7684\uff1a<\/p>\n<pre class=\"brush:c\">\tconst int i=5;\r\n\tint a[i]={1,2,3,4,5};<\/pre>\n<p>\u8bf8\u59825\uff0c\u201chello\u201d\u8fd9\u6837\u7684\u5e38\u91cf\u4ee5\u53ca\u5b8f\u5b9a\u4e49\u8fc7\u7684\u5e38\u91cf\u4e4b\u6240\u4ee5\u4e0d\u80fd\u88ab\u4fee\u6539\u662f\u56e0\u4e3a\u5728\u5185\u5b58\u4e2d\u6ca1\u6709\u4e3a\u4ed6\u4eec\u5206\u914d\u7a7a\u95f4\uff0c\u5b83\u4eec\u5b58\u50a8\u5728\u8fd0\u7b97\u5355\u5143\u7684\u5bc4\u5b58\u5668\u4e2d\u3002\u800c\u4e0a\u8ff0\u6240\u8a00\u7684const\u4fee\u6539\u8fc7\u7684\u53d8\u91cf\u8bf4\u5230\u5e95\u8fd8\u662f\u4e00\u4e2a\u53d8\u91cf\uff0c\u5185\u5b58\u4e2d\u6709\u5b58\u50a8\u90a3\u4e2a\u53d8\u91cf\u7684\u5730\u65b9\u3002\u53ea\u4e0d\u8fc7\uff0c\u8fd9\u4e2a\u53d8\u91cf\u6709\u4e9b\u7279\u6b8a\uff1a\u53ea\u80fd\u8bfb\u53d6\u3002\u73b0\u5728\u518d\u770b\u4e0a\u9762\u7684\u4ee3\u7801\uff0c\u7531\u4e8ei\u4e3a\u53d8\u91cf\uff0c\u5b83\u4e0d\u80fd\u7528\u6765\u521d\u59cb\u5316\u6570\u7ec4\u7684\u5927\u5c0f\u3002<\/p>\n<p>\u63a5\u7740\u770b\u4e0b\u9762\u7684\u4ee3\u7801\uff1a<\/p>\n<pre class=\"brush:c\">typedef char * charp;\r\nchar string[4] = \"abc\";\r\nconst char *p1 = string;\r\nconst charp p2 = string;\r\np1++;\r\np2++;<\/pre>\n<p>\u6700\u540e\u4e00\u53e5\u4f1a\u62a5\u9519\uff0c\u4e3a\u4ec0\u4e48\uff1f<\/p>\n<p>\u5728\u7b2c\u4e09\u53e5\u4e2d\uff0cp1\u662f\u53ef\u53d8\u7684\uff0c\u800c*p\u662fconst\u7684\uff1b\u7b2c\u56db\u53e5\u4e2d\uff0cp2\u662fconst\u7684\uff0c\u56e0\u6b64\u4e0d\u80fd\u8fdb\u884c++\uff1b\u4e5f\u8bb8\u4f60\u6b64\u65f6\u5bf9p\u548c*p\u54ea\u4e00\u4e2a\u4e3aconst\u5f88\u8ff7\u60d1\u3002\u4f46\u662f\u6ca1\u6709\u5173\u7cfb\uff0c\u8fd9\u91cc\u6709\u4e00\u4e2a\u5c0f\u6280\u5de7\uff1a<strong>\u5c06\u4e0a\u8ff0\u8bed\u53e5\u4e2d\u7684\u6570\u636e\u7c7b\u578b\u53bb\u6389\uff0c\u79bbconst\u6700\u8fd1\u7684\u5c31\u662f\u53ea\u8bfb\u7684<\/strong>\u3002\u6bd4\u5982const char *p1 = string\u53bb\u6389char\u540e\uff0c*p\u79bbconst\u6700\u8fd1\uff0c\u90a3\u4e48*p\u662fconst\u7684\uff1b\u518d\u5982const charp p2 = string\u53bb\u6389\u6570\u636e\u7c7b\u578bcharp\u540e\uff0cp2\u79bbconst\u6700\u8fd1\uff0c\u90a3\u4e48p2\u5c31\u662f\u4e0d\u53ef\u6539\u53d8\u7684\u3002<\/p>\n<p>\u4e0d\u8fc7\uff0c\u5bf9\u4e8e\u7c7b\u4f3cconst (char *)p1 = string;\u8fd9\u6837\u7684\u8bed\u53e5\uff0c\u4e0a\u8ff0\u529e\u6cd5\u6709\u70b9\u963b\u788d\u3002\u4e0d\u8fc7\u4f60\u53ef\u4ee5\u5c06\uff08char*\uff09\u770b\u6210\u4e00\u4e2a\u6574\u4f53\uff08\u4f60\u4e5f\u53ef\u4ee5\u8ba4\u4e3a\u662f\u7528typedef\u5b9a\u4e49\u4e86\u4e00\u4e2a\u65b0\u7c7b\u578b\uff09\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u7ee7\u7eed\u7528\u4e0a\u9762\u7684\u65b9\u6cd5\u3002<\/p>\n<h4><strong><em>enum<\/em><\/strong><\/h4>\n<p>\u5173\u4e8e\u4e2d\u65ad\u5904\u7406\u51fd\u6570\u7684\u8fd4\u56de\u503c\u7c7b\u578b\uff0c\u6709\u4e0b\u9762\u7684\u5b9a\u4e49\uff1a<\/p>\n<pre class=\"brush:c\">\/\/linux\/include\/linux\/interrupt.h\r\n 98typedef irqreturn_t (*irq_handler_t)(int, void *);\r\n\/\/linux\/include\/linux\/irqreturn.h\r\n 10enum irqreturn {\r\n 11        IRQ_NONE,\r\n 12        IRQ_HANDLED,\r\n 13        IRQ_WAKE_THREAD,\r\n 14};\r\n 15\r\n 16typedef enum irqreturn irqreturn_t;<\/pre>\n<p>\u6709\u4e00\u4e9b\u4e66\u4e0a\u4f7f\u7528\u7684\u662fint\u578b\uff0c\u5e76\u4e14\u4f7f\u7528int\u4e5f\u53ef\u4ee5\u901a\u8fc7\u3002\u8fd9\u662f\u4e3a\u4ec0\u4e48\uff1f<\/p>\n<p>\u5176\u5b9e\uff0c\u4e86\u89e3\u4e86\u679a\u4e3e\u7c7b\u578b\u7684\u672c\u8d28\uff0c\u8fd9\u4e2a\u95ee\u9898\u5c31\u4e00\u76ee\u4e86\u7136\u4e86\u3002\u679a\u4e3e\u7c7b\u578b\u7684\u5b9a\u4e49\u5f62\u5f0f\u5982\u4e0b\uff1a<\/p>\n<p><em>enum<\/em><br \/>\n{ \u679a\u4e3e\u5e38\u91cf1\uff0c\u679a\u4e3e\u5e38\u91cf2\uff0c\u2026\u2026\uff0c\u679a\u4e3e\u5e38\u91cfn};<\/p>\n<p>\u800c\u679a\u4e3e\u5e38\u91cf\u662f\u7528\u6807\u793a\u7b26\u8868\u793a\u7684\u6574\u5f62\u5e38\u91cf\u3002\u5e76\u4e14C\u8bed\u8a00\u89c4\u5b9a\u679a\u4e3e\u5e38\u91cf\u7684\u9ed8\u8ba4\u503c\u4f9d\u6b21\u4e3a\uff1a0\uff0c1\uff0c\u2026\u2026\uff0cn-1\u3002\u5bf9\u5e94\u5230\u4e0a\u9762\u7684\u5b9a\u4e49\u4ee3\u7801\uff0cenum irqreturn\u4e2d\u4e09\u4e2a\u5e38\u91cf\u7684\u503c\u5373\u4e3a0\uff0c1\uff0c2\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>const \u6211\u4eec\u53ef\u4ee5\u5c06const\u5173\u952e\u5b57\u6240\u4fee\u9970\u7684\u53d8\u91cf\u770b\u4f5c\u662f\u53ea\u8bfb\u53d8\u91cf\uff0c\u4e5f\u5c31\u662f\u8bf4\u8fd9\u4e2a\u53d8\u91cf\u4e0d\u53ef\u88ab\u4fee\u6539\uff0c\u53ea\u80fd\u8bfb\u53d6\u5176\u503c\u3002\u4f46 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[74],"tags":[401],"class_list":["post-1756","post","type-post","status-publish","format-standard","hentry","category-c","tag-c"],"views":5858,"_links":{"self":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/1756","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/comments?post=1756"}],"version-history":[{"count":0,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/1756\/revisions"}],"wp:attachment":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/media?parent=1756"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/categories?post=1756"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/tags?post=1756"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}