{"id":6054,"date":"2024-08-21T13:01:01","date_gmt":"2024-08-21T05:01:01","guid":{"rendered":""},"modified":"2024-08-21T13:01:01","modified_gmt":"2024-08-21T05:01:01","slug":"typeid\u8be6\u89e3_type\u4ec0\u4e48\u63a5\u53e3","status":"publish","type":"post","link":"https:\/\/mushiming.com\/6054.html","title":{"rendered":"typeid\u8be6\u89e3_type\u4ec0\u4e48\u63a5\u53e3"},"content":{"rendered":"<p>typeid\u662fC++\u7684\u5173\u952e\u5b57\u4e4b\u4e00\uff0c\u7b49\u540c\u4e8esizeof\u8fd9\u7c7b\u7684\u64cd\u4f5c\u7b26\u3002typeid\u64cd\u4f5c\u7b26\u7684\u8fd4\u56de\u7ed3\u679c\u662f\u540d\u4e3atype_info\u7684\u6807\u51c6\u5e93\u7c7b\u578b\u7684\u5bf9\u8c61\u7684\u5f15\u7528\uff08\u5728\u5934\u6587\u4ef6typeinfo\u4e2d\u5b9a\u4e49\uff0c\u7a0d\u540e\u6211\u4eec\u770b\u4e00\u4e0bvs\u548cgcc\u5e93\u91cc\u9762\u7684\u6e90\u7801\uff09\uff0c\u5b83\u7684\u8868\u8fbe\u5f0f\u6709\u4e0b\u56fe\u4e24\u79cd\u5f62\u5f0f\u3002<br \/>&nbsp;&nbsp;&nbsp;&nbsp;<br \/>&nbsp;&nbsp;&nbsp;&nbsp;<img decoding=\"async\" src=\"http:\/\/www.cppblog.com\/images\/cppblog_com\/smagle\/typeid.jpg\" =\"\" =\"\" alt=\"typeid\u8be6\u89e3_type\u4ec0\u4e48\u63a5\u53e3 (https:\/\/mushiming.com\/)  \u7b2c1\u5f20\" title=\"typeid\u8be6\u89e3_type\u4ec0\u4e48\u63a5\u53e3  \u7b2c1\u5f20-\u7a46\u4e16\u660e\u535a\u5ba2\" ><br \/>&nbsp;&nbsp;&nbsp;&nbsp;\u5982\u679c\u8868\u8fbe\u5f0f\u7684\u7c7b\u578b\u662f\u7c7b\u7c7b\u578b\u4e14\u81f3\u5c11\u5305\u542b\u6709\u4e00\u4e2a\u865a\u51fd\u6570\uff0c\u5219typeid\u64cd\u4f5c\u7b26\u8fd4\u56de\u8868\u8fbe\u5f0f\u7684\u52a8\u6001\u7c7b\u578b\uff0c\u9700\u8981\u5728\u8fd0\u884c\u65f6\u8ba1\u7b97\uff1b\u5426\u5219\uff0ctypeid\u64cd\u4f5c\u7b26\u8fd4\u56de\u8868\u8fbe\u5f0f\u7684\u9759\u6001\u7c7b\u578b\uff0c\u5728\u7f16\u8bd1\u65f6\u5c31\u53ef\u4ee5\u8ba1\u7b97\u3002<\/p>\n<p>&nbsp;&nbsp; &nbsp; gcc v4.4\u4e0btypeinfo\u7684\u6e90\u7801\u5982\u4e0b\uff1a<\/p>\n<p>&nbsp;&nbsp; &nbsp; &nbsp; &nbsp;<textarea name=\"code\" class=\"cpp\">class type_info { public: virtual ~type_info(); const char* name() const { return __name; } #if !__GXX_TYPEINFO_EQUALITY_INLINE bool before(const type_info&amp; __arg) const; bool operator==(const type_info&amp; __arg) const; #else #if !__GXX_MERGED_TYPEINFO_NAMES #error \"Inline implementation of type_info comparision requires merging of type_info objects\" #endif bool before(const type_info&amp; __arg) const { return __name &lt; __arg.__name; } bool operator==(const type_info&amp; __arg) const { return __name == __arg.__name; } #endif bool operator!=(const type_info&amp; __arg) const { return !operator==(__arg); } virtual bool __is_pointer_p() const; virtual bool __is_function_p() const; virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj, unsigned __outer) const; virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target, void **__obj_ptr) const; protected: const char *__name; explicit type_info(const char *__n): __name(__n) { } private: \/\/\/ Assigning type_info is not supported. type_info&amp; operator=(const type_info&amp;); type_info(const type_info&amp;); };<\/textarea>&nbsp;<\/p>\n<p>ISO C++\u6807\u51c6\u5e76\u6ca1\u6709\u786e\u5207\u5b9a\u4e49type_info\uff0c\u5b83\u7684\u786e\u5207\u5b9a\u4e49\u7f16\u8bd1\u5668\u76f8\u5173\u7684\uff0c\u4f46\u662f\u6807\u51c6\u5374\u89c4\u5b9a\u4e86\u5176\u5b9e\u73b0\u5fc5\u9700\u63d0\u4f9b\u5982\u4e0b\u56db\u79cd\u64cd\u4f5c\uff08\u5728\u4e4b\u540e\u7684\u7ae0\u8282\u4e2d\u6211\u4f1a\u6765\u5206\u6790type_info\u7c7b\u6587\u4ef6\u7684\u6e90\u7801\uff09\uff1a <\/p>\n<table border=\"1\" cellspacing=\"1\" cellpadding=\"1\">\n<tbody>\n<tr>\n<td>&nbsp;t1 == t2<\/td>\n<td>&nbsp;\u5982\u679c\u4e24\u4e2a\u5bf9\u8c61t1\u548ct2\u7c7b\u578b\u76f8\u540c\uff0c\u5219\u8fd4\u56detrue\uff1b\u5426\u5219\u8fd4\u56defalse<\/td>\n<\/tr>\n<tr>\n<td>&nbsp;t1 != t2<\/td>\n<td>&nbsp;\u5982\u679c\u4e24\u4e2a\u5bf9\u8c61t1\u548ct2\u7c7b\u578b\u4e0d\u540c\uff0c\u5219\u8fd4\u56detrue\uff1b\u5426\u5219\u8fd4\u56defalse<\/td>\n<\/tr>\n<tr>\n<td>&nbsp;t.name()<\/td>\n<td>&nbsp;\u8fd4\u56de\u7c7b\u578b\u7684C-style\u5b57\u7b26\u4e32\uff0c\u7c7b\u578b\u540d\u5b57\u7528\u7cfb\u7edf\u76f8\u5173\u7684\u65b9\u6cd5\u4ea7\u751f<\/td>\n<\/tr>\n<tr>\n<td>&nbsp;t1.before(t2)<\/td>\n<td>&nbsp;\u8fd4\u56de\u6307\u51fat1\u662f\u5426\u51fa\u73b0\u5728t2\u4e4b\u524d\u7684bool\u503c<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;&nbsp;&nbsp; type_info\u7c7b\u63d0\u4f9b\u4e86public\u865a \u6790\u6784\u51fd\u6570\uff0c\u4ee5\u4f7f\u7528\u6237\u80fd\u591f\u7528\u5176\u4f5c\u4e3a\u57fa\u7c7b\u3002\u5b83\u7684\u9ed8\u8ba4\u6784\u9020\u51fd\u6570\u548c\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u53ca\u8d4b\u503c\u64cd\u4f5c\u7b26\u90fd\u5b9a\u4e49\u4e3aprivate\uff0c\u6240\u4ee5\u4e0d\u80fd\u5b9a\u4e49\u6216\u590d\u5236type_info\u7c7b\u578b\u7684\u5bf9\u8c61\u3002\u7a0b\u5e8f\u4e2d\u521b\u5efatype_info\u5bf9\u8c61\u7684\u552f\u4e00\u65b9\u6cd5\u662f\u4f7f\u7528typeid\u64cd\u4f5c\u7b26\uff08\u7531\u6b64\u53ef\u89c1\uff0c\u5982\u679c\u628atypeid\u770b\u4f5c\u51fd\u6570\u7684\u8bdd\uff0c\u5176\u5e94\u8be5\u662ftype_info\u7684 \u53cb\u5143\uff09\u3002type_info\u7684name\u6210\u5458\u51fd\u6570\u8fd4\u56deC-style\u7684\u5b57\u7b26\u4e32\uff0c\u7528\u6765\u8868\u793a\u76f8\u5e94\u7684\u7c7b\u578b\u540d\uff0c\u4f46\u52a1\u5fc5\u6ce8\u610f\u8fd9\u4e2a\u8fd4\u56de\u7684\u7c7b\u578b\u540d\u4e0e\u7a0b\u5e8f\u4e2d\u4f7f\u7528\u7684\u76f8\u5e94\u7c7b\u578b\u540d\u5e76\u4e0d\u4e00\u5b9a\u4e00\u81f4\uff08\u5f80\u5f80\u5982\u6b64\uff0c\u89c1\u540e\u9762\u7684\u7a0b\u5e8f\uff09\uff0c\u8fd9\u5177\u4f53\u7531\u7f16\u8bd1\u5668\u7684\u5b9e\u73b0\u6240\u51b3\u5b9a\u7684\uff0c\u6807\u51c6\u53ea\u8981\u6c42\u5b9e\u73b0\u4e3a\u6bcf\u4e2a\u7c7b\u578b\u8fd4\u56de\u552f\u4e00\u7684\u5b57\u7b26\u4e32\u3002type_info\u7684==\u3001\uff01=\u548cbefore() \u7b49\u4e3b\u8981\u662f\u5bf9\u4e8ename\u5b57\u7b26\u4e32\u7684\u6bd4\u5bf9\u3002<\/p>\n<p>&nbsp;&nbsp; &nbsp;\u4e0b\u9762\u901a\u8fc7\u4ee3\u7801\u6765\u5c55\u793a\uff1a<\/p>\n<p><textarea name=\"code\" class=\"cpp\">#include &lt;iostream&gt; #include &lt;typeinfo&gt; using namespace std; class base { public: \/\/ virtual void say() { cout &lt;&lt; \"Base\" &lt;&lt; endl;} }; class child : public base { public: \/\/ virtual void say() { cout &lt;&lt; \"child\" &lt;&lt; endl;} }; int main(int argc, char* argv[]) { base* p = NULL; child d; p = &amp;d; base&amp; d_d = d; cout &lt;&lt; typeid(int).name() &lt;&lt;endl &lt;&lt; typeid(unsigned int).name() &lt;&lt; endl &lt;&lt; typeid(double).name() &lt;&lt; endl &lt;&lt; typeid(string).name() &lt;&lt; endl &lt;&lt; typeid(base).name() &lt;&lt; endl &lt;&lt; typeid(p).name() &lt;&lt; endl &lt;&lt; typeid(child).name() &lt;&lt; endl &lt;&lt; typeid(d).name() &lt;&lt; endl &lt;&lt; typeid(d_d).name() &lt;&lt; endl; } <\/textarea>&nbsp;<\/p>\n<p>gcc\u4e0b\u8fd0\u884c\u7ed3\u679c\uff1a<\/p>\n<\/p>\n<p>i<\/p>\n<p>j<\/p>\n<p>d<\/p>\n<p>Ss<\/p>\n<p>4base<\/p>\n<p>P4base<\/p>\n<p>5child<\/p>\n<p>5child<\/p>\n<p>4base<\/p>\n<div><\/div>\n<div>\n  \u82e5\u53bb\u6389\u4e0a\u9762\u4e24\u5904\u6ce8\u91ca\uff0c\u8fd0\u884c\u7ed3\u679c\u5982\u4e0b\uff1a\n<\/div>\n<div>\n<div>\n   i\n <\/div>\n<div>\n   j\n <\/div>\n<div>\n   d\n <\/div>\n<div>\n   Ss\n <\/div>\n<div>\n   4base\n <\/div>\n<div>\n   P4base\n <\/div>\n<div>\n   5child\n <\/div>\n<div>\n   5child\n <\/div>\n<div>\n   5child\n <\/div>\n<\/div>\n<div><\/div>\n<div>\n  &nbsp;&nbsp; \u5f53typeid\u4f5c\u7528\u4e8e\u6307\u9488\u65f6\uff0c\u770b\u5230\u7684\u662f\u57fa\u7c7b\u7684\u7c7b\u578b\uff0c\u800c\u4e0d\u8bba\u57fa\u7c7b\u662f\u5426\u5305\u542b\u865a\u51fd\u6570\u3002\u4f5c\u7528\u4e8e\u5f15\u7528\u65f6\uff0c\u5f53typeid\u64cd\u4f5c\u7b26\u7684\u64cd\u4f5c\u6570\u662f\u4e0d\u5e26\u6709\u865a\u51fd\u6570\u7684\u7c7b\u7c7b\u578b\u65f6\uff0ctypeid\u64cd\u4f5c\u7b26\u4f1a\u6307\u51fa\u64cd\u4f5c\u6570\u7684\u7c7b\u578b\uff0c\u800c\u4e0d\u662f\u5e95\u5c42\u5bf9\u8c61\u7684\u7c7b\u578b\u3002\u5982\u679ctypeid\u64cd\u4f5c\u7b26\u7684\u64cd\u4f5c\u6570\u662f\u81f3\u5c11\u5305\u542b\u4e00\u4e2a\u865a\u62df\u51fd\u6570\u7684\u7c7b\u7c7b\u578b\u65f6\uff0c\u5e76\u4e14\u8be5\u8868\u8fbe\u5f0f\u662f\u4e00\u4e2a\u57fa\u7c7b\u7684\u5e94\u7528\uff0c\u5219typeid\u64cd\u4f5c\u7b26\u6307\u51fa\u5e95\u5c42\u5bf9\u8c61\u7684\u6d3e\u751f\u7c7b\u7c7b\u578b\u3002\n<\/div>\n<div><\/div>\n<div>\n  &nbsp;&nbsp; \u611f\u8c22\uff1a http:\/\/www.cppblog.com\/smagle\/archive\/2010\/05\/14\/115286.html\n<\/div><\/p>\n","protected":false},"excerpt":{"rendered":"typeid\u8be6\u89e3_type\u4ec0\u4e48\u63a5\u53e3typeid\u662fC++\u7684\u5173\u952e\u5b57\u4e4b\u4e00\uff0c\u7b49\u540c\u4e8esizeof\u8fd9\u7c7b\u7684\u64cd\u4f5c\u7b26","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"_links":{"self":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/6054"}],"collection":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/comments?post=6054"}],"version-history":[{"count":0,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/6054\/revisions"}],"wp:attachment":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/media?parent=6054"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/categories?post=6054"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/tags?post=6054"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}