{"id":182,"date":"2022-03-03T23:48:32","date_gmt":"2022-03-03T15:48:32","guid":{"rendered":"https:\/\/chenqinghe.com\/?p=182"},"modified":"2022-03-03T23:49:59","modified_gmt":"2022-03-03T15:49:59","slug":"go%e8%af%bb%e5%8f%96%e4%bb%bb%e6%84%8f%e5%86%85%e5%ad%98%e5%9c%b0%e5%9d%80%e7%9a%84%e4%bb%bb%e6%84%8f%e5%ad%97%e8%8a%82%e6%95%b0%e6%8d%ae","status":"publish","type":"post","link":"https:\/\/chenqinghe.com\/?p=182","title":{"rendered":"Go\u8bfb\u53d6\u4efb\u610f\u5185\u5b58\u5730\u5740\u7684\u4efb\u610f\u5b57\u8282\u6570\u636e"},"content":{"rendered":"<p>\u5728\u4ecb\u7ecd\u8bfb\u53d6\u65b9\u6cd5\u4e4b\u524d\uff0c\u9996\u5148\u4ecb\u7ecd\u4e24\u79cd\u7c7b\u578b\uff1aunsafe.Pointer \u548cuintptr\u3002<\/p>\n<p>unsafe.Pointer\u4ee3\u8868\u7684\u662f\u4efb\u610f\u7c7b\u578b\u7684\u6307\u9488\uff0c\u5b83\u652f\u6301\u56db\u79cd\u7279\u6709\u7684\u64cd\u4f5c\uff1a<\/p>\n<ol>\n<li>\u4efb\u610f\u7c7b\u578b\u7684\u6307\u9488\u53d8\u91cf\u90fd\u53ef\u4ee5\u8f6c\u6362\u4e3aunsafe.Pointer<\/li>\n<li>unsafe.Pointer\u53ef\u4ee5\u8f6c\u6362\u4e3a\u4efb\u610f\u7c7b\u578b\u7684\u6307\u9488\u53d8\u91cf<\/li>\n<li>uintptr\u53ef\u4ee5\u8f6c\u6362\u4e3aunsafe.Pointer<\/li>\n<li>unsafe.Pointer\u53ef\u4ee5\u8f6c\u6362\u4e3auintptr<\/li>\n<\/ol>\n<p>\u6211\u4eec\u77e5\u9053\u5728Go\u4e2d\uff0c\u4e0d\u540c\u7c7b\u578b\u7684\u6307\u9488\u662f\u4e0d\u53ef\u4ee5\u76f8\u4e92\u8f6c\u6362\u7684\uff0c\u4f46\u662f\u6839\u636e\u4ee5\u4e0a\u7684\u7279\u6027\uff0c\u5c31\u53ef\u4ee5\u501f\u52a9unsafe.Pointer\u4f5c\u4e3a\u8df3\u677f<strong>\u5b9e\u73b0\u4e0d\u540c\u7c7b\u578b\u7684\u6307\u9488\u4e4b\u95f4\u7684\u76f8\u4e92\u8f6c\u6362<\/strong>\u3002<\/p>\n<p>\u540c\u65f6\uff0cGo\u4e2d\u7684\u6307\u9488\u662f\u4e0d\u80fd\u8fdb\u884c\u8fd0\u7b97\u7684\uff0c\u5305\u62ecunsafe.Pointer\uff0c\u4f46\u662fuintptr\u662f\u53ef\u4ee5\u7684\uff0c\u800cuintptr\u548cunsafe.Pointer\u53ef\u4ee5\u4e92\u76f8\u8f6c\u6362\uff0c\u56e0\u6b64\u53ef\u4ee5\u7528\u6765<strong>\u5b9e\u73b0\u6307\u9488\u7684\u8fd0\u7b97<\/strong>\u3002<\/p>\n<\/p>\n<p>\u63a5\u4e0b\u6765\u4ecb\u7ecd\u4e00\u4e9b\u53d8\u91cf\u53ca\u5176\u5728\u5185\u5b58\u4e2d\u7684\u5b58\u50a8\u65b9\u6cd5\u3002<\/p>\n<p>\u4f8b\u5982\u4ee5\u4e0b\u7ed3\u6784\uff1a<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"golang\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">type T struct {\n\tF1 int32\n\tF2 rune\n\tF3 int64\n\tF4 *string\n}\n\nvar t T<\/pre>\n<p>\u5219\u53d8\u91cft\u5728\u5185\u5b58\u4e2d\u7684\u5e03\u5c40\u53ef\u89c1\u4e0b\u56fe\uff1a<\/p>\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" layer-src=\"https:\/\/chenqinghe.com\/wp-content\/uploads\/2022\/03\/image-1.png\" src=\"https:\/\/chenqinghe.com\/wp-content\/uploads\/2022\/03\/image-1.png\" alt=\"\u300aGo\u8bfb\u53d6\u4efb\u610f\u5185\u5b58\u5730\u5740\u7684\u4efb\u610f\u5b57\u8282\u6570\u636e\u300b\" \/><\/figure>\n<p>\u5176\u4e2d\u53d8\u91cft\u7684\u6307\u9488&amp;t\u6307\u5411\u7684\u662ft\u5728\u5185\u5b58\u4e2d\u7684\u8d77\u59cb\u5730\u5740\u3002\u5b57\u6bb5F1\u4e3aint32\u7c7b\u578b\uff0c\u53604\u4e2a\u5b57\u8282\uff1bF2\u4e3arune\uff0c\u662fint32\u7684\u522b\u540d\uff0c\u4e5f\u53604\u4e2a\u5b57\u8282\uff1bF3\u4e3aint64\uff0c\u5360\u75288\u4e2a\u5b57\u8282\uff0c\u6700\u540e\u662fF4\u662f*string\u7c7b\u578b\uff0c\u4e5f\u662f\u4e2a\u6307\u9488\uff0c\u6240\u4ee5\u4e5f\u5360\u75288\u4e2a\u5b57\u8282\u3002<\/p>\n<p>\u5728\u5185\u5b58\u5b58\u50a8\u4e2d\uff0c\u662f\u6ca1\u6709\u53d8\u91cf\u7c7b\u578b\u4fe1\u606f\u7684\uff0c\u5176\u5185\u90e8\u5b58\u653e\u7684\u5185\u5bb9\u5230\u5e95\u5982\u4f55\u5904\u7406\uff0c\u7531\u53d8\u91cf\u7684\u7c7b\u578b\u6765\u51b3\u5b9a\u3002\u6bd4\u5982\u8bf4\u4e0a\u56fe\u4e2d\u7684F1\u5b57\u6bb5\uff0c\u5047\u8bbe\u5b58\u50a8\u7684\u5185\u5bb9\u4e3a0x01\uff0c\u4f5c\u4e3aint32\u503c\u89e3\u6790\u65f6\u4e3a1\uff0c\u4f5c\u4e3abool\u503c\u89e3\u6790\u65f6\u5c31\u4e3atrue\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u53ea\u8981\u6211\u77e5\u9053\u5185\u5b58\u5730\u5740\uff0c\u7136\u540e\u4efb\u610f\u7ed9\u5b9a\u4e00\u4e2a\u7c7b\u578b\uff0c\u5c31\u80fd\u5f97\u5230\u8fd9\u4e2a\u5730\u5740\u91cc\u7684\u5185\u5bb9\u4f5c\u4e3a\u8fd9\u4e2a\u7c7b\u578b\u5904\u7406\u65f6\u5f97\u5230\u7684\u503c\u3002<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"golang\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func main() {\n\tt := T{\n\t\tF1: 1,\n\t\tF2: 2,\n\t}\n\tprintln(t.F1)\n\n\tb := *(*bool)(unsafe.Pointer(&amp;t))\n\tprintln(b)\n\n}\n\/\/ output:\n1\ntrue<\/pre>\n<p>\u65e2\u7136\u4efb\u610f\u7c7b\u578b\u90fd\u53ef\u4ee5\uff0c\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u4ee5<strong>\u5b57\u8282\u6570\u7ec4<\/strong>\u7c7b\u578b\u6765\u89e3\u6790\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u62ff\u5230\u5185\u5b58\u4e2d\u7684\u6bcf\u4e2a\u5b57\u8282\u7684\u6570\u636e\u4e86\u3002<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"golang\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func main() {\n\tt := T{\n\t\tF1: 1,\n\t\tF2: 2,\n\t}\n\tfmt.Println(t.F1)\n\n\tb := *(*bool)(unsafe.Pointer(&amp;t))\n\tfmt.Println(b)\n\n\tvar arr [4]byte\n\tarr = *(*[4]byte)(unsafe.Pointer(&amp;t))\n\tfmt.Println(arr)\n}\n\/\/ output:\n1\ntrue\n[1 0 0 0]<\/pre>\n<p>\u7531\u4e0a\u9762\u56fe\u4e2d\u53ef\u4ee5\u770b\u5230\uff0cF2\u5b57\u6bb5\u7684\u5730\u5740\u8d77\u59cb\u662f\u5728F1\u5b57\u6bb5\u5730\u5740(\u4e5f\u5373\u53d8\u91cft\u7684\u8d77\u59cb\u5730\u5740)\u540e\u504f\u79fb4\u4e2a\u5b57\u8282\uff0c\u90a3\u4e48\u53ef\u4ee5\u901a\u8fc7\u6307\u9488\u8fd0\u7b97\u7684\u65b9\u5f0f\u5f97\u5230F2\u5b57\u6bb5\u7684\u5730\u5740\u53ca\u5185\u90e8\u5b58\u50a8\u7684\u5185\u5bb9\uff1a<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"golang\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func main() {\n\tt := T{\n\t\tF1: 1,\n\t\tF2: 2,\n\t}\n\n\t\/\/ \u6b64\u5904\u53ea\u4f5c\u4e3a\u6f14\u793a\uff0c\u7528\u6cd5\u6709\u4e0d\u59a5\u7684\u5730\u65b9\n\t\/\/ \u5177\u4f53\u6b63\u786e\u7528\u6cd5\u8bf7\u89c1unsafe.Pointer\u7684\u6e90\u7801\u6ce8\u91ca\n\tp2 := uintptr(unsafe.Pointer(&amp;t)) + 4\n\n\tfmt.Println(*(*[4]byte)(unsafe.Pointer(p2)))\n}\n\n\/\/ output:\n[2 0 0 0]<\/pre>\n<p>uintptr\u5176\u5b9e\u5c31\u662f\u4e2a\u6574\u6570\uff0c\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u5b9e\u73b0\u4ee5\u4e0b\u7684\u65b9\u6cd5\u6765\u8bfb\u53d6\u4efb\u610f\u5730\u5740(\u5f53\u7136\u5730\u5740\u662f\u5426\u5408\u6cd5\u53e6\u8bf4)\u76844\u4e2a\u5b57\u8282\u7684\u6570\u636e\uff1a<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"golang\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func readMemory(addr uintptr) [4]byte {\n\treturn *(*[4]byte)(unsafe.Pointer(addr))\n}\n<\/pre>\n<p>\u73b0\u5728\u6211\u4eec\u5df2\u7ecf\u5b9e\u73b0\u4e86\u8bfb\u53d6\u4efb\u610f\u5730\u5740\u76844\u4e2a\u5b57\u8282\u7684\u6570\u636e\uff0c\u90a3\u6709\u4ec0\u4e48\u529e\u6cd5\u6765\u8bfb\u53d6\u4efb\u610f\u5b57\u8282\u7684\u6570\u636e\u5462\uff1fGo\u4e2d\u7684\u6570\u7ec4\u7ed3\u6784\u957f\u5ea6\u662f\u56fa\u5b9a\u7684\uff0c\u5e76\u4e14\u65e0\u6cd5\u901a\u8fc7\u53d8\u91cf\u6765\u6307\u5b9a\u957f\u5ea6\u3002\u4f46\u662f\u6211\u4eec\u6709\u5207\u7247(slice)\u554a\uff01<\/p>\n<p>\u90fd\u77e5\u9053\u5207\u7247\u7684\u5e95\u5c42\u7ed3\u6784\u662f\u7531\u6570\u636e\u5730\u5740\u3001\u957f\u5ea6\u3001\u5bb9\u91cf\u4e09\u4e2a\u5b57\u6bb5\u7ec4\u6210\u7684\u7ed3\u6784\u4f53\uff0c\u5176\u4e0ereflect.SliceHeader\u4fdd\u6301\u4e00\u81f4\uff0c\u90a3\u4e48\u6211\u4eec\u53ea\u8981\u5c06\u4e0a\u9762\u4ee3\u7801\u505a\u5982\u4e0b\u6539\u52a8\u5373\u53ef\uff1a<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"golang\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func readMemory(addr uintptr, size int) []byte {\n\treturn *(*[]byte)(unsafe.Pointer(&amp;reflect.SliceHeader{\n\t\tData: addr,\n\t\tLen:  size,\n\t\tCap:  size,\n\t}))\n}\n<\/pre>\n<p>\u8fd9\u6837\uff0c\u5c31\u5b9e\u73b0\u4e86\u8bfb\u53d6\u4efb\u610f\u5185\u5b58\u5730\u5740\u4efb\u610f\u5b57\u8282\u6570\u636e\u7684\u529f\u80fd\u3002\u521a\u624d\u53ea\u662f\u8bfb\u4e86\u5355\u4e2a\u5b57\u6bb5\u30014\u4e2a\u5b57\u8282\u7684\u6570\u636e\uff0c\u73b0\u5728\u53ef\u4ee5\u5c1d\u8bd5\u76f4\u63a5\u8bfb\u53d6\u524d\u4e24\u4e2a\u5b57\u6bb5\u603b\u51718\u4e2a\u5b57\u8282\u7684\u6570\u636e\u4e86\uff1a<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"golang\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">func main() {\n\tt := T{\n\t\tF1: 1,\n\t\tF2: 2,\n\t}\n\n\tfmt.Println(readMemory(uintptr(unsafe.Pointer(&amp;t)), 8))\n}\n\/\/ output\uff1a\n[1 0 0 0 2 0 0 0]<\/pre>\n<p>\u5b8c\u7f8e\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728\u4ecb\u7ecd\u8bfb\u53d6\u65b9\u6cd5\u4e4b\u524d\uff0c\u9996\u5148\u4ecb\u7ecd\u4e24\u79cd\u7c7b\u578b\uff1aunsafe.Pointer \u548cuintptr\u3002 unsafe.Pointer\u4ee3\u8868\u7684\u662f\u4efb\u610f\u7c7b\u578b\u7684\u6307\u9488\uff0c\u5b83\u652f\u6301\u56db\u79cd\u7279\u6709\u7684\u64cd\u4f5c\uff1a \u4efb\u610f\u7c7b\u578b\u7684\u6307\u9488\u53d8\u91cf\u90fd\u53ef\u4ee5\u8f6c\u6362\u4e3aunsafe.Pointer unsafe.Pointer\u53ef\u4ee5\u8f6c\u6362\u4e3a\u4efb\u610f\u7c7b\u578b\u7684\u6307\u9488\u53d8\u91cf uintptr\u53ef\u4ee5\u8f6c\u6362\u4e3aunsafe.Pointer un\u2026\u2026<\/p>\n","protected":false},"author":1,"featured_media":185,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[9],"tags":[],"_links":{"self":[{"href":"https:\/\/chenqinghe.com\/index.php?rest_route=\/wp\/v2\/posts\/182"}],"collection":[{"href":"https:\/\/chenqinghe.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chenqinghe.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chenqinghe.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chenqinghe.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=182"}],"version-history":[{"count":0,"href":"https:\/\/chenqinghe.com\/index.php?rest_route=\/wp\/v2\/posts\/182\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/chenqinghe.com\/index.php?rest_route=\/wp\/v2\/media\/185"}],"wp:attachment":[{"href":"https:\/\/chenqinghe.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=182"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chenqinghe.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=182"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chenqinghe.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=182"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}