{"@attributes":{"version":"2.0"},"channel":{"title":"14March","link":"https:\/\/hcraM41.github.io\/","description":"Recent content on 14March","generator":"Hugo -- gohugo.io","language":"zh-cn","copyright":"Ycz","lastBuildDate":"Sat, 10 May 2025 23:03:15 +0800","item":[{"title":"defer","link":"https:\/\/hcraM41.github.io\/p\/defer\/","pubDate":"Sat, 10 May 2025 23:03:15 +0800","guid":"https:\/\/hcraM41.github.io\/p\/defer\/","description":"\"Featured

\u4e00\u3001defer\u7684\u7b80\u5355\u4f7f\u7528\n<\/h2>

defer<\/code> \u62e5\u6709\u6ce8\u518c\u5ef6\u8fdf\u8c03\u7528\u7684\u673a\u5236\uff0cdefer<\/code> \u5173\u952e\u5b57\u540e\u9762\u8ddf\u968f\u7684\u8bed\u53e5\u6216\u8005\u51fd\u6570\uff0c\u4f1a\u5728\u5f53\u524d\u7684\u51fd\u6570return<\/code> \u6b63\u5e38\u7ed3\u675f \u6216\u8005 panic<\/code> \u5f02\u5e38\u7ed3\u675f \u540e\u6267\u884c\u3002<\/strong><\/p>\n

\u4f46\u662fdefer<\/code> \u53ea\u6709\u5728\u6ce8\u518c\u540e\uff0c\u6700\u540e\u624d\u80fd\u751f\u6548\u8c03\u7528\u6267\u884c\uff0creturn<\/code> \u4e4b\u540e\u7684defer<\/code> \u8bed\u53e5\u662f\u4e0d\u4f1a\u6267\u884c\u7684\uff0c\u56e0\u4e3a\u5e76\u6ca1\u6709\u6ce8\u518c\u6210\u529f\u3002<\/p>\n

\u5982\u4e0b\u4f8b\u5b50\uff1a<\/p>\n

func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>111<\/span>)<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>222<\/span>)<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>333<\/span>)<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
\u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
222<\/span>\n<\/span><\/span>111<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
\u89e3\u6790\uff1a222<\/code> \u3001111<\/code> \u662f\u5728return<\/code> \u4e4b\u524d\u6ce8\u518c\u7684\uff0c\u6240\u4ee5\u5982\u671f\u6267\u884c\uff0c333<\/code> \u662f\u5728return <\/code> \u4e4b\u540e\u6ce8\u518c\u7684\uff0c\u6ce8\u518c\u5931\u8d25\uff0c\u6267\u884c\u4e0d\u4e86\u3002<\/p>\n
defer<\/code> \u5728\u9700\u8981\u8d44\u6e90\u91ca\u653e\u7684\u573a\u666f\u975e\u5e38\u6709\u7528\uff0c\u53ef\u4ee5\u5f88\u65b9\u4fbf\u5730\u5728\u51fd\u6570\u7ed3\u675f\u524d\u6267\u884c\u4e00\u4e9b\u64cd\u4f5c\u3002<\/p>\n
\u6bd4\u5982\u5728 \u6253\u5f00\u8fde\u63a5\/\u5173\u95ed\u8fde\u63a5 \u3001\u52a0\u9501\/\u91ca\u653e\u9501\u3001\u6253\u5f00\u6587\u4ef6\/\u5173\u95ed\u6587\u4ef6 \u8fd9\u4e9b\u573a\u666f\u4e0b\uff1a<\/p>\n
file<\/span>,<\/span> err<\/span> :=<\/span> os<\/span>.<\/span>Open<\/span>(<\/span>"1.txt"<\/span>)<\/span>\n<\/span><\/span>if<\/span> err<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>    panic<\/span>(<\/span>err<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>if<\/span> file<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>    defer<\/span> file<\/span>.<\/span>Close<\/span>()<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
\u8fd9\u91cc\u8981\u6ce8\u610f\u7684\u662f\uff1a\u5728\u8c03\u7528file.Close()<\/code> \u4e4b\u524d\uff0c\u9700\u8981\u5224\u65adfile<\/code> \u662f\u5426\u4e3a\u7a7a\uff0c\u907f\u514d\u51fa\u73b0\u5f02\u5e38\u60c5\u51b5\u3002<\/p>\n
\u518d\u6765\u770b\u4e00\u4e2a\u9519\u8bef\u793a\u8303\uff0c\u6ca1\u6709\u6b63\u786e\u4f7f\u7528defer<\/code> \u7684\u4f8b\u5b50\uff1a<\/p>\n
player<\/span>.<\/span>mu<\/span>.<\/span>Lock<\/span>()<\/span>\n<\/span><\/span>rand<\/span>.<\/span>Intn<\/span>(<\/span>number<\/span>)<\/span>\n<\/span><\/span>player<\/span>.<\/span>mu<\/span>.<\/span>Unlock<\/span>()<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
\u8fd9\u4e09\u884c\u4ee3\u7801\uff0c\u5b58\u5728\u4e24\u4e2a\u95ee\u9898\uff1a\n1. \u4e2d\u95f4\u8fd9\u884c\u4ee3\u7801 rand.Intn(number)<\/code> \u662f\u6709\u53ef\u80fd\u53d1\u751fpanic<\/code> \u7684\uff0c\u8fd9\u5c31\u4f1a\u5bfc\u81f4\u6ca1\u6709\u6b63\u5e38\u89e3\u9501\u3002\n2. \u8fd9\u6837\u7684\u4ee3\u7801\u5728\u9879\u76ee\u4e2d\u540e\u7eed\u53ef\u80fd\u88ab\u5176\u4ed6\u4eba\u4fee\u6539\uff0c\u5728rand.Intn(number)<\/code> \u540e\u589e\u52a0\u66f4\u591a\u7684\u903b\u8f91\uff0c\u8fd9\u662f\u5b8c\u5168\u4e0d\u53ef\u63a7\u7684\u3002<\/p>\n
\u5728Lock<\/code> \u548c Unlock<\/code> \u4e4b\u95f4\u7684\u4ee3\u7801\u4e00\u65e6\u51fa\u73b0 panic<\/code> \uff0c\u5c31\u4f1a\u9020\u6210\u6b7b\u9501\u3002\u56e0\u6b64\uff0c\u5373\u4f7f\u903b\u8f91\u975e\u5e38\u7b80\u5355\uff0c\u4f7f\u7528defer<\/code> \u4e5f\u662f\u5f88\u6709\u5fc5\u8981\u7684\uff0c\u56e0\u4e3a\u9700\u6c42\u603b\u5728\u53d8\u5316\uff0c\u4ee3\u7801\u4e5f\u603b\u4f1a\u88ab\u4fee\u6539\u3002<\/p>\n
\n
\u4e8c\u3001defer\u7684\u51fd\u6570\u53c2\u6570\u4e0e\u95ed\u5305\u5f15\u7528\n<\/h2>
defer<\/code> \u5ef6\u8fdf\u8bed\u53e5\u4e0d\u4f1a\u9a6c\u4e0a\u6267\u884c\uff0c\u800c\u662f\u4f1a\u8fdb\u5165\u4e00\u4e2a\u6808\uff0c\u51fd\u6570return<\/code> \u524d\uff0c\u4f1a\u6309\u5148\u8fdb\u540e\u51fa<\/strong>\u7684\u987a\u5e8f\u6267\u884c\u3002<\/p>\n
\u5148\u8fdb\u540e\u51fa\u7684\u539f\u56e0\u662f\u540e\u9762\u5b9a\u4e49\u7684\u51fd\u6570\u53ef\u80fd\u4f1a\u4f9d\u8d56\u524d\u9762\u7684\u8d44\u6e90\uff0c\u81ea\u7136\u8981\u5148\u6267\u884c\uff1b\u5426\u5219\uff0c\u5982\u679c\u524d\u9762\u7684\u5148\u6267\u884c\u4e86\uff0c\u90a3\u4e48\u540e\u9762\u51fd\u6570\u7684\u4f9d\u8d56\u5c31\u6ca1\u6709\u4e86\uff0c\u5c31\u53ef\u80fd\u4f1a\u5bfc\u81f4\u51fa\u9519\u3002<\/p>\n
\u5728defer<\/code> \u51fd\u6570\u5b9a\u4e49\u65f6\uff0c\u5bf9\u5916\u90e8\u53d8\u91cf\u7684\u5f15\u7528\u6709\u4e09\u79cd\u65b9\u5f0f\uff1a\u503c\u4f20\u53c2\u3001\u6307\u9488\u4f20\u53c2\u3001\u95ed\u5305\u5f15\u7528\u3002<\/font><\/u><\/p>\n
    \n
  1. \u503c\u4f20\u53c2\uff1a\u5728defer<\/code> \u5b9a\u4e49\u65f6\u5c31\u628a\u503c\u4f20\u9012\u7ed9defer<\/code> \uff0c\u5e76\u590d\u5236\u4e00\u4efdcache\u8d77\u6765\uff0cdefer\u8c03\u7528\u65f6\u548c\u5b9a\u4e49\u7684\u65f6\u5019\u503c\u662f\u4e00\u81f4\u7684\u3002<\/strong><\/li>\n
  2. \u6307\u9488\u4f20\u53c2\uff1a\u5728defer<\/code> \u5b9a\u4e49\u65f6\u5c31\u628a\u6307\u9488\u4f20\u9012\u7ed9defer<\/code> \uff0cdefer\u8c03\u7528\u65f6\u6839\u636e\u6574\u4e2a\u4e0a\u4e0b\u6587\u786e\u5b9a\u53c2\u6570\u5f53\u524d\u7684\u503c\u3002<\/strong><\/li>\n
  3. \u95ed\u5305\u5f15\u7528\uff1a\u5728defer<\/code> \u5b9a\u4e49\u65f6\u5c31\u628a\u503c\u5f15\u7528\u4f20\u9012\u7ed9defer<\/code> \uff0cdefer\u8c03\u7528\u65f6\u6839\u636e\u6574\u4e2a\u4e0a\u4e0b\u6587\u786e\u5b9a\u53c2\u6570\u5f53\u524d\u7684\u503c\u3002<\/strong><\/li>\n<\/ol>\n
    \u4e0b\u9762\u901a\u8fc7\u4f8b\u5b50\u52a0\u6df1\u4e00\u4e0b\u7406\u89e3\u3002<\/p>\n
    \u4f8b\u5b501\uff1a<\/p>\n
    func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tvar<\/span> arr<\/span> [<\/span>4<\/span>]<\/span>struct<\/span>{}<\/span>\n<\/span><\/span>\n<\/span><\/span>\tfor<\/span> i<\/span> :=<\/span> range<\/span> arr<\/span> {<\/span>\n<\/span><\/span>\t\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>i<\/span>)<\/span>\n<\/span><\/span>\t\t}()<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
    3<\/span>\n<\/span><\/span>3<\/span>\n<\/span><\/span>3<\/span>\n<\/span><\/span>3<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u89e3\u6790\uff1a\u56e0\u4e3adefer<\/code> \u540e\u9762\u8ddf\u7740\u7684\u662f\u4e00\u4e2a\u95ed\u5305\uff0c\u6839\u636e\u6574\u4e2a\u4e0a\u4e0b\u6587\u786e\u5b9a\uff0cfor<\/code> \u5faa\u73af\u7ed3\u675f\u540ei<\/code> \u7684\u503c\u4e3a3\uff0c\u56e0\u6b64\u6700\u540e\u6253\u5370\u4e864\u4e2a3\u3002<\/p>\n
    \u4f8b\u5b502\uff1a<\/p>\n
    func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tvar<\/span> n<\/span> int<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ \u503c\u4f20\u53c2<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>(<\/span>n1<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>n1<\/span>)<\/span>\n<\/span><\/span>\t}(<\/span>n<\/span>)<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ \u6307\u9488\u4f20\u53c2<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>(<\/span>n2<\/span> *<\/span>int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>*<\/span>n2<\/span>)<\/span>\n<\/span><\/span>\t}(<\/span>&<\/span>n<\/span>)<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ \u95ed\u5305<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>n<\/span>)<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\n<\/span><\/span>\tn<\/span> =<\/span> 4<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
    4<\/span>\n<\/span><\/span>4<\/span>\n<\/span><\/span>0<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u89e3\u6790\uff1a<\/p>\n
    defer<\/code> \u6267\u884c\u987a\u5e8f\u548c\u5b9a\u4e49\u7684\u987a\u5e8f\u662f\u76f8\u53cd\u7684\uff1b<\/p>\n
    \u7b2c\u4e09\u4e2adefer<\/code> \u8bed\u53e5\u662f\u95ed\u5305\uff0c\u5f15\u7528\u7684\u5916\u90e8\u53d8\u91cfn<\/code> \uff0cdefer\u8c03\u7528\u65f6\u6839\u636e\u4e0a\u4e0b\u6587\u786e\u5b9a\uff0c\u6700\u7ec8\u7ed3\u679c\u662f4\uff1b<\/p>\n
    \u7b2c\u4e8c\u4e2adefer<\/code> \u8bed\u53e5\u662f\u6307\u9488\u4f20\u53c2\uff0cdefer\u8c03\u7528\u65f6\u6839\u636e\u6574\u4e2a\u4e0a\u4e0b\u6587\u786e\u5b9a\u53c2\u6570\u5f53\u524d\u7684\u503c\uff0c\u6700\u7ec8\u7ed3\u679c\u662f4\uff1b<\/p>\n
    \u7b2c\u4e00\u4e2adefer<\/code> \u8bed\u53e5\u662f\u503c\u4f20\u53c2\uff0cdefer\u8c03\u7528\u65f6\u548c\u5b9a\u4e49\u7684\u65f6\u5019\u503c\u662f\u4e00\u81f4\u7684\uff0c\u6700\u7ec8\u7ed3\u679c\u662f0\uff1b<\/p>\n
    \u4f8b\u5b503\uff1a<\/p>\n
    func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\/\/ \u6587\u4ef61<\/span>\n<\/span><\/span>\tf<\/span>,<\/span> _<\/span> :=<\/span> os<\/span>.<\/span>Open<\/span>(<\/span>"1.txt"<\/span>)<\/span>\n<\/span><\/span>\tif<\/span> f<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\tdefer<\/span> func<\/span>(<\/span>f<\/span> io<\/span>.<\/span>Closer<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\t\tif<\/span> err<\/span> :=<\/span> f<\/span>.<\/span>Close<\/span>();<\/span> err<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\t\t\tfmt<\/span>.<\/span>Printf<\/span>(<\/span>"defer close file err 1 %v\\n"<\/span>,<\/span> err<\/span>)<\/span>\n<\/span><\/span>\t\t\t}<\/span>\n<\/span><\/span>\t\t}(<\/span>f<\/span>)<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ \u6587\u4ef62<\/span>\n<\/span><\/span>\tf<\/span>,<\/span> _<\/span> =<\/span> os<\/span>.<\/span>Open<\/span>(<\/span>"2.txt"<\/span>)<\/span>\n<\/span><\/span>\tif<\/span> f<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\tdefer<\/span> func<\/span>(<\/span>f<\/span> io<\/span>.<\/span>Closer<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\t\tif<\/span> err<\/span> :=<\/span> f<\/span>.<\/span>Close<\/span>();<\/span> err<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\t\t\tfmt<\/span>.<\/span>Printf<\/span>(<\/span>"defer close file err 2 %v\\n"<\/span>,<\/span> err<\/span>)<\/span>\n<\/span><\/span>\t\t\t}<\/span>\n<\/span><\/span>\t\t}(<\/span>f<\/span>)<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>"success"<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
    success<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u89e3\u6790\uff1a\u5148\u8bf4\u7ed3\u8bba\uff0c\u8fd9\u4e2a\u4f8b\u5b50\u7684\u4ee3\u7801\u6ca1\u6709\u95ee\u9898\uff0c\u4e24\u4e2a\u6587\u4ef6\u90fd\u4f1a\u88ab\u6210\u529f\u5173\u95ed\u3002\u8fd9\u4e2a\u662f\u5bf9defer<\/code> \u539f\u7406\u7684\u5e94\u7528\uff0c\u56e0\u4e3adefer<\/code> \u51fd\u6570\u5728\u5b9a\u4e49\u7684\u65f6\u5019\uff0c\u53c2\u6570\u5c31\u5df2\u7ecf\u590d\u5236\u8fdb\u53bb\u4e86\uff0c\u8fd9\u91cc\u662f\u503c\u4f20\u53c2\uff0c\u771f\u6b63\u6267\u884cclose()<\/code> \u51fd\u6570\u7684\u65f6\u5019\u5c31\u521a\u597d\u5173\u95ed\u7684\u662f\u6b63\u786e\u7684\u6587\u4ef6\u3002\u5982\u679c\u4e0d\u628af<\/code> \u5f53\u505a\u503c\u4f20\u53c2\uff0c\u6700\u540e\u4e24\u4e2aclose()<\/code> \u51fd\u6570\u5173\u95ed\u7684\u5c31\u662f\u540c\u4e00\u4e2a\u6587\u4ef6\u4e86\uff0c\u90fd\u662f\u6700\u540e\u6253\u5f00\u7684\u90a3\u4e2a\u6587\u4ef6\u3002<\/p>\n
    \u4f8b\u5b503\u7684\u9519\u8bef\u793a\u8303\uff1a<\/p>\n
    func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\/\/ \u6587\u4ef61<\/span>\n<\/span><\/span>\tf<\/span>,<\/span> _<\/span> :=<\/span> os<\/span>.<\/span>Open<\/span>(<\/span>"1.txt"<\/span>)<\/span>\n<\/span><\/span>\tif<\/span> f<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\t\tif<\/span> err<\/span> :=<\/span> f<\/span>.<\/span>Close<\/span>();<\/span> err<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\t\t\tfmt<\/span>.<\/span>Printf<\/span>(<\/span>"defer close file err 1 %v\\n"<\/span>,<\/span> err<\/span>)<\/span>\n<\/span><\/span>\t\t\t}<\/span>\n<\/span><\/span>\t\t}()<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ \u6587\u4ef62<\/span>\n<\/span><\/span>\tf<\/span>,<\/span> _<\/span> =<\/span> os<\/span>.<\/span>Open<\/span>(<\/span>"2.txt"<\/span>)<\/span>\n<\/span><\/span>\tif<\/span> f<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\t\tif<\/span> err<\/span> :=<\/span> f<\/span>.<\/span>Close<\/span>();<\/span> err<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\t\t\tfmt<\/span>.<\/span>Printf<\/span>(<\/span>"defer close file err 2 %v\\n"<\/span>,<\/span> err<\/span>)<\/span>\n<\/span><\/span>\t\t\t}<\/span>\n<\/span><\/span>\t\t}()<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>"success"<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
    success<\/span>\n<\/span><\/span>defer<\/span> close<\/span> file<\/span> err<\/span> 1<\/span> close<\/span> 2.<\/span>txt<\/span>:<\/span> file<\/span> already<\/span> closed<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u4f8b\u5b504\uff1a<\/p>\n
    \/\/ \u503c\u4f20\u53c2<\/span>\n<\/span><\/span>func<\/span> func1<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tvar<\/span> err<\/span> error<\/span>\n<\/span><\/span>\tdefer<\/span> fmt<\/span>.<\/span>Println<\/span>(<\/span>err<\/span>)<\/span>\n<\/span><\/span>\terr<\/span> =<\/span> errors<\/span>.<\/span>New<\/span>(<\/span>"func1 error"<\/span>)<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>\/\/ \u95ed\u5305<\/span>\n<\/span><\/span>func<\/span> func2<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tvar<\/span> err<\/span> error<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>err<\/span>)<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\terr<\/span> =<\/span> errors<\/span>.<\/span>New<\/span>(<\/span>"func2 error"<\/span>)<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>\/\/ \u503c\u4f20\u53c2<\/span>\n<\/span><\/span>func<\/span> func3<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tvar<\/span> err<\/span> error<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>(<\/span>err<\/span> error<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>err<\/span>)<\/span>\n<\/span><\/span>\t}(<\/span>err<\/span>)<\/span>\n<\/span><\/span>\terr<\/span> =<\/span> errors<\/span>.<\/span>New<\/span>(<\/span>"func3 error"<\/span>)<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>\/\/ \u6307\u9488\u4f20\u53c2<\/span>\n<\/span><\/span>func<\/span> func4<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tvar<\/span> err<\/span> error<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>(<\/span>err<\/span> *<\/span>error<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>*<\/span>err<\/span>)<\/span>\n<\/span><\/span>\t}(<\/span>&<\/span>err<\/span>)<\/span>\n<\/span><\/span>\terr<\/span> =<\/span> errors<\/span>.<\/span>New<\/span>(<\/span>"func4 error"<\/span>)<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tfunc1<\/span>()<\/span>\n<\/span><\/span>\tfunc2<\/span>()<\/span>\n<\/span><\/span>\tfunc3<\/span>()<\/span>\n<\/span><\/span>\tfunc4<\/span>()<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
    <<\/span>nil<\/span>><\/span>\n<\/span><\/span>func2<\/span> error<\/span>\n<\/span><\/span><<\/span>nil<\/span>><\/span>\n<\/span><\/span>func4<\/span> error<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
    \u89e3\u6790\uff1a<\/p>\n
    \u7b2c\u4e00\u4e2a\u548c\u7b2c\u4e09\u4e2a\u51fd\u6570\u4e2d\uff0c\u90fd\u662f\u4f5c\u4e3a\u53c2\u6570\uff0c\u8fdb\u884c\u503c\u4f20\u53c2\uff0cerr<\/code> \u5728\u5b9a\u4e49\u7684\u65f6\u5019\u5c31\u4f1a\u6c42\u503c\uff0c\u56e0\u4e3a\u5b9a\u4e49\u7684\u65f6\u5019\u503c\u90fd\u662fnil<\/code> \uff0c\u6240\u4ee5\u6700\u540e\u7684\u7ed3\u679c\u90fd\u662fnil<\/code> \uff1b<\/p>\n
    \u7b2c\u4e8c\u4e2a\u51fd\u6570\u7684\u53c2\u6570\u5728\u5b9a\u4e49\u7684\u65f6\u5019\u4e5f\u6c42\u503c\u4e86\uff0c\u4f46\u662f\u5b83\u662f\u4e2a\u95ed\u5305\uff0c\u67e5\u770b\u4e0a\u4e0b\u6587\u53d1\u73b0\u6700\u540e\u503c\u88ab\u4fee\u6539\u4e3afunc2 error<\/code> \uff1b<\/p>\n
    \u7b2c\u56db\u4e2a\u51fd\u6570\u662f\u6307\u9488\u4f20\u53c2\uff0c\u6700\u540e\u503c\u88ab\u4fee\u6539\u4e3afunc4 error<\/code> \uff1b<\/p>\n
    \u73b0\u5b9e\u4e2d\uff0c\u7b2c\u4e09\u4e2a\u51fd\u6570\u95ed\u5305\u7684\u4f8b\u5b50\u662f\u6bd4\u8f83\u5bb9\u6613\u72af\u7684\u9519\u8bef\uff0c\u5bfc\u81f4\u6700\u540edefer<\/code> \u8bed\u53e5\u6ca1\u6709\u8d77\u5230\u4f5c\u7528\uff0c\u9020\u6210\u751f\u4ea7\u4e0a\u7684\u4e8b\u6545\uff0c\u9700\u8981\u7279\u522b\u6ce8\u610f\u3002<\/strong><\/p>\n
    \n
    \u4e09\u3001defer\u7684\u8bed\u53e5\u62c6\u89e3\n<\/h2>
    \u4ece\u8fd4\u56de\u503c\u51fa\u53d1\u6765\u62c6\u89e3\u5ef6\u8fdf\u8bed\u53e5 defer<\/code> \u3002<\/p>\n
    \u200b\treturn xxx<\/code><\/p>\n
    \u8fd9\u6761\u8bed\u53e5\u7ecf\u8fc7\u7f16\u8bd1\u4e4b\u540e\uff0c\u5b9e\u9645\u4e0a\u751f\u6210\u4e86\u4e09\u6761\u6307\u4ee4\uff1a<\/p>\n
      \n
    1. \u8fd4\u56de\u503c = xxx<\/strong><\/li>\n
    2. \u8c03\u7528 defer \u51fd\u6570<\/strong><\/li>\n
    3. \u7a7a\u7684 return<\/strong><\/li>\n<\/ol>\n
      \u5176\u4e2d\uff0c1<\/code> \u548c 3<\/code> \u662freturn<\/code> \u8bed\u53e5\u751f\u6210\u7684\u6307\u4ee4\uff0c2<\/code> \u662fdefer<\/code> \u8bed\u53e5\u751f\u6210\u7684\u6307\u4ee4\u3002\u53ef\u4ee5\u770b\u51fa\uff1a<\/p>\n
      return<\/code> \u5e76\u4e0d\u662f\u4e00\u6761\u539f\u5b50\u6307\u4ee4\uff1bdefer<\/code> \u8bed\u53e5\u5728\u7b2c\u4e8c\u6b65\u8c03\u7528\uff0c\u8fd9\u91cc\u53ef\u80fd\u64cd\u4f5c\u8fd4\u56de\u503c\uff0c\u4ece\u800c\u5f71\u54cd\u6700\u7ec8\u7ed3\u679c\u3002<\/strong><\/p>\n
      \u63a5\u4e0b\u6765\u901a\u8fc7\u4f8b\u5b50\u6765\u52a0\u6df1\u7406\u89e3\u3002<\/p>\n
      \u4f8b\u5b501\uff1a<\/p>\n
      func<\/span> func1<\/span>()<\/span> (<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\tt<\/span> :=<\/span> 3<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tt<\/span> =<\/span> t<\/span> +<\/span> 3<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\n<\/span><\/span>\treturn<\/span> t<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tr<\/span> :=<\/span> func1<\/span>()<\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>r<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
      3<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u8bed\u53e5\u62c6\u89e3\uff1a<\/p>\n
      func<\/span> func1<\/span>()<\/span> (<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\tt<\/span> :=<\/span> 3<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 1.\u8fd4\u56de\u503c=xxx\uff1a\u8d4b\u503c\u6307\u4ee4<\/span>\n<\/span><\/span>\tr<\/span> =<\/span> t<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 2.\u8c03\u7528defer\u51fd\u6570\uff1adefer\u5728\u8d4b\u503c\u4e0e\u8fd4\u56de\u4e4b\u524d\u6267\u884c\uff0c\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\u8fd4\u56de\u503cr\u6ca1\u6709\u88ab\u4fee\u6539\u8fc7<\/span>\n<\/span><\/span>\tfunc<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tt<\/span> =<\/span> t<\/span> +<\/span> 3<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 3.\u7a7a\u7684return<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tr<\/span> :=<\/span> func1<\/span>()<\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>r<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1a\u56e0\u4e3a\u7b2c\u4e8c\u4e2a\u6b65\u9aa4\u91cc\u5e76\u6ca1\u6709\u64cd\u4f5c\u8fd4\u56de\u503cr<\/code> \uff0c\u6240\u4ee5\u6700\u7ec8\u5f97\u5230\u7684\u7ed3\u679c\u662f3<\/code> \u3002<\/p>\n
      \u4f8b\u5b502\uff1a<\/p>\n
      func<\/span> func2<\/span>()<\/span> (<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>(<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\tr<\/span> =<\/span> r<\/span> +<\/span> 3<\/span>\n<\/span><\/span>\t}(<\/span>r<\/span>)<\/span>\n<\/span><\/span>\n<\/span><\/span>\treturn<\/span> 1<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tr<\/span> :=<\/span> func2<\/span>()<\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>r<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
      1<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u8bed\u53e5\u62c6\u89e3\uff1a<\/p>\n
      func<\/span> func2<\/span>()<\/span> (<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 1.\u8fd4\u56de\u503c=xxx\uff1a\u8d4b\u503c\u6307\u4ee4<\/span>\n<\/span><\/span>\tr<\/span> =<\/span> 1<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 2.\u8c03\u7528defer\u51fd\u6570\uff1a\u56e0\u4e3a\u662f\u503c\u4f20\u53c2\uff0c\u6240\u4ee5\u4fee\u6539\u7684r\u662f\u4e2a\u590d\u5236\u7684\u503c\uff0c\u4e0d\u4f1a\u5f71\u54cd\u8981\u8fd4\u56de\u7684\u90a3\u4e2ar\u503c\u3002<\/span>\n<\/span><\/span>\tfunc<\/span>(<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\t\tr<\/span> =<\/span> r<\/span> +<\/span> 3<\/span>\n<\/span><\/span>\t}(<\/span>r<\/span>)<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 3.\u7a7a\u7684return<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tr<\/span> :=<\/span> func2<\/span>()<\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>r<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1a\u56e0\u4e3a\u7b2c\u4e8c\u4e2a\u6b65\u9aa4\u91cc\u6539\u53d8\u7684\u662f\u4f20\u503c\u8fdb\u53bb\u7684r<\/code> \u503c\uff0c\u662f\u4e00\u4e2a\u5f62\u53c2\u7684\u590d\u5236\u503c\uff0c\u4e0d\u4f1a\u5f71\u54cd\u5b9e\u53c2r<\/code> \uff0c\u6240\u4ee5\u6700\u7ec8\u5f97\u5230\u7684\u7ed3\u679c\u662f1<\/code> \u3002<\/p>\n
      \u4f8b\u5b503\uff1a<\/p>\n
      func<\/span> func3<\/span>()<\/span> (<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tr<\/span> =<\/span> r<\/span> +<\/span> 3<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\n<\/span><\/span>\treturn<\/span> 1<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tr<\/span> :=<\/span> func3<\/span>()<\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>r<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
      4<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u8bed\u53e5\u62c6\u89e3\uff1a<\/p>\n
      func<\/span> func3<\/span>()<\/span> (<\/span>r<\/span> int<\/span>)<\/span> {<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 1.\u8fd4\u56de\u503c=xxx\uff1a\u8d4b\u503c\u6307\u4ee4<\/span>\n<\/span><\/span>\tr<\/span> =<\/span> 1<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 2.\u8c03\u7528defer\u51fd\u6570\uff1a\u56e0\u4e3a\u662f\u95ed\u5305\uff0c\u6355\u83b7\u7684\u53d8\u91cf\u662f\u5f15\u7528\u4f20\u9012\uff0c\u6240\u4ee5\u4f1a\u4fee\u6539\u8fd4\u56de\u7684\u90a3\u4e2ar\u503c\u3002<\/span>\n<\/span><\/span>\tfunc<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tr<\/span> =<\/span> r<\/span> +<\/span> 3<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ 3.\u7a7a\u7684return<\/span>\n<\/span><\/span>\treturn<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tr<\/span> :=<\/span> func3<\/span>()<\/span>\n<\/span><\/span>\tfmt<\/span>.<\/span>Println<\/span>(<\/span>r<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1a\u56e0\u4e3a\u7b2c\u4e8c\u4e2a\u6b65\u9aa4\u91cc\u6539\u53d8\u7684r<\/code> \u503c\u662f\u95ed\u5305\uff0c\u95ed\u5305\u4e2d\u6355\u83b7\u7684\u53d8\u91cf\u662f\u5f15\u7528\u4f20\u9012\uff0c\u4e0d\u662f\u503c\u4f20\u9012\uff0c\u6240\u4ee5\u6700\u7ec8\u5f97\u5230\u7684\u7ed3\u679c\u662f4<\/code> \u3002<\/p>\n
      \n
      \u56db\u3001defer\u4e2d\u7684recover\n<\/h2>
      \u4ee3\u7801\u4e2d\u7684panic<\/code> \u6700\u7ec8\u4f1a\u88abrecover<\/code> \u6355\u83b7\u5230\u3002\u5728\u65e5\u5e38\u5f00\u53d1\u4e2d\uff0c\u53ef\u80fd\u67d0\u4e00\u6761\u534f\u8bae\u7684\u903b\u8f91\u89e6\u53d1\u4e86\u67d0\u4e00\u4e2abug<\/code> \u9020\u6210panic<\/code> \uff0c\u8fd9\u65f6\u5c31\u53ef\u4ee5\u7528recover<\/code> \u53bb\u6355\u83b7panic<\/code> \uff0c\u7a33\u4f4f\u4e3b\u6d41\u7a0b\uff0c\u4e0d\u5f71\u54cd\u5176\u4ed6\u534f\u8bae\u7684\u4e1a\u52a1\u903b\u8f91\u3002<\/p>\n
      \u9700\u8981\u6ce8\u610f\u7684\u662f\uff0crecover<\/code> \u51fd\u6570\u53ea\u5728defer<\/code> \u7684\u51fd\u6570\u4e2d\u76f4\u63a5\u8c03\u7528\u624d\u751f\u6548\u3002<\/strong><\/p>\n
      \u901a\u8fc7\u4f8b\u5b50\u770brecover<\/code> \u8c03\u7528\u60c5\u51b5\u3002<\/p>\n
      \u4f8b\u5b501\uff1a<\/p>\n
      func<\/span> func1<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tif<\/span> err<\/span> :=<\/span> recover<\/span>();<\/span> err<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>"func1 recover"<\/span>,<\/span> err<\/span>)<\/span>\n<\/span><\/span>\t\treturn<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tdefer<\/span> func1<\/span>()<\/span>\n<\/span><\/span>\tpanic<\/span>(<\/span>"func1 panic"<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
      func1<\/span> recover<\/span> func1<\/span> panic<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1a\u6b63\u786erecover<\/code> \uff0c\u56e0\u4e3a\u5728defer<\/code> \u4e2d\u8c03\u7528\u7684\uff0c\u6240\u4ee5\u53ef\u4ee5\u751f\u6548\u3002<\/p>\n
      \u4f8b\u5b502\uff1a<\/p>\n
      func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\trecover<\/span>()<\/span>\n<\/span><\/span>\tpanic<\/span>(<\/span>"func2 panic"<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
      panic<\/span>:<\/span> func2<\/span> panic<\/span>\n<\/span><\/span>\n<\/span><\/span>goroutine<\/span> 1<\/span> [<\/span>running<\/span>]:<\/span>\n<\/span><\/span>main<\/span>.<\/span>main<\/span>()<\/span>\n<\/span><\/span>        C<\/span>:<\/span>\/<\/span>Users<\/span>\/<\/span>ycz<\/span>\/<\/span>go<\/span>\/<\/span>ccc<\/span>.<\/span>go<\/span>:<\/span>5<\/span> +<\/span>0x31<\/span>\n<\/span><\/span>exit<\/span> status<\/span> 2<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1a\u9519\u8befrecover<\/code> \uff0c\u76f4\u63a5\u8c03\u7528recover<\/code> \uff0c\u8fd4\u56denil<\/code> \u3002<\/p>\n
      \u4f8b\u5b503\uff1a<\/p>\n
      func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tdefer<\/span> recover<\/span>()<\/span>\n<\/span><\/span>\tpanic<\/span>(<\/span>"func3 panic"<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
      panic<\/span>:<\/span> func3<\/span> panic<\/span>\n<\/span><\/span>\n<\/span><\/span>goroutine<\/span> 1<\/span> [<\/span>running<\/span>]:<\/span>\n<\/span><\/span>main<\/span>.<\/span>main<\/span>()<\/span>\n<\/span><\/span>        C<\/span>:<\/span>\/<\/span>Users<\/span>\/<\/span>ycz<\/span>\/<\/span>go<\/span>\/<\/span>ccc<\/span>.<\/span>go<\/span>:<\/span>5<\/span> +<\/span>0x65<\/span>\n<\/span><\/span>exit<\/span> status<\/span> 2<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1a\u9519\u8befrecover<\/code> \uff0crecover<\/code> \u9700\u8981\u5728defer<\/code> \u7684\u51fd\u6570\u91cc\u8c03\u7528\u3002<\/p>\n
      \u4f8b\u5b504\uff1a<\/p>\n
      func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\t\trecover<\/span>()<\/span>\n<\/span><\/span>\t\t}()<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>\tpanic<\/span>(<\/span>"func4 panic"<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u6267\u884c\u7ed3\u679c\uff1a<\/p>\n
      panic<\/span>:<\/span> func4<\/span> panic<\/span>\n<\/span><\/span>\n<\/span><\/span>goroutine<\/span> 1<\/span> [<\/span>running<\/span>]:<\/span>\n<\/span><\/span>main<\/span>.<\/span>main<\/span>()<\/span>\n<\/span><\/span>        C<\/span>:<\/span>\/<\/span>Users<\/span>\/<\/span>ycz<\/span>\/<\/span>go<\/span>\/<\/span>ccc<\/span>.<\/span>go<\/span>:<\/span>9<\/span> +<\/span>0x49<\/span>\n<\/span><\/span>exit<\/span> status<\/span> 2<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1a\u9519\u8befrecover<\/code> \uff0c\u4e0d\u80fd\u5728\u591a\u91cddefer<\/code> \u5d4c\u5957\u91cc\u8c03\u7528recover<\/code> \u3002<\/p>\n
      \u53e6\u5916\u9700\u8981\u6ce8\u610f\u7684\u4e00\u70b9\u662f\uff0c\u7236goroutine<\/code> \u65e0\u6cd5 recover<\/code> \u4f4f \u5b50goroutine<\/code> \u7684 panic<\/code> \u3002<\/strong><\/p>\n
      \u539f\u56e0\u662f\uff0cgoroutine<\/code> \u88ab\u8bbe\u8ba1\u4e3a\u4e00\u4e2a\u72ec\u7acb\u7684\u4ee3\u7801\u6267\u884c\u5355\u5143\uff0c\u62e5\u6709\u81ea\u5df1\u7684\u6267\u884c\u6808\uff0c\u4e0d\u4e0e\u5176\u4ed6goroutine<\/code> \u5171\u4eab\u4efb\u4f55\u7684\u6570\u636e\u3002<\/p>\n
      \u4e5f\u5c31\u662f\u8bf4\uff0c\u65e0\u6cd5\u8ba9goroutine<\/code> \u62e5\u6709\u8fd4\u56de\u503c\uff0c\u4e5f\u65e0\u6cd5\u8ba9goroutine<\/code> \u62e5\u6709\u81ea\u8eab\u7684ID<\/code> \u7f16\u53f7\u3002<\/p>\n
      \u5982\u679c\u5e0c\u671b\u6709\u4e00\u4e2a\u5168\u5c40\u7684panic<\/code> \u6355\u83b7\u4e2d\u5fc3\uff0c\u90a3\u4e48\u53ef\u4ee5\u901a\u8fc7channel<\/code> \u6765\u5b9e\u73b0\uff0c\u5982\u4e0b\u793a\u4f8b\uff1a<\/p>\n
      var<\/span> panicNotifyManage<\/span> chan<\/span> interface<\/span>{}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> StartGlobalPanicRecover<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tpanicNotifyManage<\/span> =<\/span> make<\/span>(<\/span>chan<\/span> interface<\/span>{})<\/span>\n<\/span><\/span>\tgo<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tselect<\/span> {<\/span>\n<\/span><\/span>\t\tcase<\/span> err<\/span> :=<\/span> <-<\/span>panicNotifyManage<\/span>:<\/span>\n<\/span><\/span>\t\t\tfmt<\/span>.<\/span>Println<\/span>(<\/span>"panicNotifyManage--->"<\/span>,<\/span> err<\/span>)<\/span>\n<\/span><\/span>\t\t}<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> GoSafe<\/span>(<\/span>f<\/span> func<\/span>())<\/span> {<\/span>\n<\/span><\/span>\tgo<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tdefer<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\t\tif<\/span> err<\/span> :=<\/span> recover<\/span>();<\/span> err<\/span> !=<\/span> nil<\/span> {<\/span>\n<\/span><\/span>\t\t\t\tpanicNotifyManage<\/span> <-<\/span> err<\/span>\n<\/span><\/span>\t\t\t}<\/span>\n<\/span><\/span>\t\t}()<\/span>\n<\/span><\/span>\t\tf<\/span>()<\/span>\n<\/span><\/span>\t}()<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> main<\/span>()<\/span> {<\/span>\n<\/span><\/span>\tStartGlobalPanicRecover<\/span>()<\/span>\n<\/span><\/span>\tf1<\/span> :=<\/span> func<\/span>()<\/span> {<\/span>\n<\/span><\/span>\t\tpanic<\/span>(<\/span>"f1 panic"<\/span>)<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\tGoSafe<\/span>(<\/span>f1<\/span>)<\/span>\n<\/span><\/span>\ttime<\/span>.<\/span>Sleep<\/span>(<\/span>time<\/span>.<\/span>Second<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u89e3\u6790\uff1aGoSafe()<\/code> \u672c\u8d28\u4e0a\u662f\u5bf9go<\/code> \u5173\u952e\u5b57\u8fdb\u884c\u4e86\u4e00\u5c42\u5c01\u88c5\uff0c\u786e\u4fdd\u5728\u6267\u884c\u5e76\u53d1\u5355\u5143\u524d\u63d2\u5165\u4e00\u4e2adefer<\/code> \uff0c\u4ece\u800c\u4fdd\u8bc1\u80fd\u591frecover<\/code> \u4f4fpanic<\/code> \u3002\u4f46\u662f\u8fd9\u4e2a\u65b9\u6848\u5e76\u4e0d\u5b8c\u7f8e\uff0c\u5982\u679c\u5f00\u53d1\u4eba\u5458\u4e0d\u4f7f\u7528GoSafe<\/code> \u51fd\u6570\u6765\u521b\u5efagoroutine<\/code> \uff0c\u800c\u662f\u81ea\u5df1\u521b\u5efa\uff0c\u5e76\u4e14\u5728\u4ee3\u7801\u4e2d\u51fa\u73b0\u4e86panic<\/code> \uff0c\u90a3\u4e48\u4ecd\u7136\u4f1a\u9020\u6210\u7a0b\u5e8f\u5d29\u6e83\u3002<\/p>\n"},{"title":"rand","link":"https:\/\/hcraM41.github.io\/p\/rand\/","pubDate":"Sat, 10 May 2025 22:26:34 +0800","guid":"https:\/\/hcraM41.github.io\/p\/rand\/","description":"\"Featured
      \u6e90\u7801\u5256\u6790\n<\/h2>
      \u901a\u8fc7\u65e5\u5e38\u968f\u673a\u6570\u7684\u4ee3\u7801\u4f7f\u7528\uff0c\u770b\u4e0brank\u5305\u5177\u4f53\u7684\u5e95\u5c42\u5b9e\u73b0\uff1a<\/p>\n
      r<\/span> :=<\/span> rand<\/span>.<\/span>New<\/span>(<\/span>rand<\/span>.<\/span>NewSource<\/span>(<\/span>time<\/span>.<\/span>Now<\/span>().<\/span>UnixNano<\/span>()))<\/span> \/\/ \u521d\u59cb\u5316\u968f\u673a\u5668<\/span>\n<\/span><\/span>r<\/span>.<\/span>Intn<\/span>(<\/span>314<\/span>)<\/span>\t\/\/ \u751f\u6210 [0, 314) \u5185\u7684\u6574\u6570<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u4ecer := rand.New(rand.NewSource(time.Now().UnixNano()))<\/code> \u5f00\u59cb\u3002<\/strong><\/p>\n
      \u521d\u59cb\u5316 Rand \u7684\u65f6\u5019\uff0c\u901a\u8fc7rand.New(rand.NewSource(seed))<\/code>\u521b\u5efa\uff0c\u6240\u4ee5\u770b\u4e0brand.New()<\/code>\u7684\u5b9e\u73b0\u3002<\/p>\n
      \/\/ New returns a new Rand that uses random values from src<\/span>\n<\/span><\/span>\/\/ to generate other random values.<\/span>\n<\/span><\/span>func<\/span> New<\/span>(<\/span>src<\/span> Source<\/span>)<\/span> *<\/span>Rand<\/span> {<\/span>\n<\/span><\/span>\ts64<\/span>,<\/span> _<\/span> :=<\/span> src<\/span>.(<\/span>Source64<\/span>)<\/span>\n<\/span><\/span>\treturn<\/span> &<\/span>Rand<\/span>{<\/span>src<\/span>:<\/span> src<\/span>,<\/span> s64<\/span>:<\/span> s64<\/span>}<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u53ef\u4ee5\u770b\u5230 Rand<\/strong> \u4f7f\u7528\u7684\u662frand.NewSource()<\/code>\u4f20\u5165\u7684 Source<\/strong>\uff0c\u56e0\u6b64\u63a5\u7740\u770b\u4e0brand.NewSource()<\/code>\u7684\u5b9e\u73b0\u3002<\/p>\n
      \/\/ NewSource returns a new pseudo-random Source seeded with the given value.<\/span>\n<\/span><\/span>\/\/ Unlike the default Source used by top-level functions, this source is not<\/span>\n<\/span><\/span>\/\/ safe for concurrent use by multiple goroutines.<\/span>\n<\/span><\/span>\/\/ The returned Source implements Source64.<\/span>\n<\/span><\/span>func<\/span> NewSource<\/span>(<\/span>seed<\/span> int64<\/span>)<\/span> Source<\/span> {<\/span>\n<\/span><\/span>\treturn<\/span> newSource<\/span>(<\/span>seed<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>func<\/span> newSource<\/span>(<\/span>seed<\/span> int64<\/span>)<\/span> *<\/span>rngSource<\/span> {<\/span>\n<\/span><\/span>\tvar<\/span> rng<\/span> rngSource<\/span>\n<\/span><\/span>\trng<\/span>.<\/span>Seed<\/span>(<\/span>seed<\/span>)<\/span>\n<\/span><\/span>\treturn<\/span> &<\/span>rng<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u770b\u5230 Source<\/strong> \u7684\u5b9e\u9645\u7c7b\u578b\u662f rngSource<\/strong>\uff0c\u5b9e\u73b0\u4e86\u63a5\u53e3 Source<\/strong>\u3002<\/p>\n
      type<\/span> rngSource<\/span> struct<\/span> {<\/span>\n<\/span><\/span>\ttap<\/span>  int<\/span>           \/\/ index into vec<\/span>\n<\/span><\/span>\tfeed<\/span> int<\/span>           \/\/ index into vec<\/span>\n<\/span><\/span>\tvec<\/span>  [<\/span>rngLen<\/span>]<\/span>int64<\/span> \/\/ current feedback register<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u770b\u4e0b\u63a5\u53e3 Source<\/strong>\u7684\u5b9a\u4e49\u3002<\/p>\n
      \/\/ A Source represents a source of uniformly-distributed<\/span>\n<\/span><\/span>\/\/ pseudo-random int64 values in the range [0, 1<<63).<\/span>\n<\/span><\/span>\/\/<\/span>\n<\/span><\/span>\/\/ A Source is not safe for concurrent use by multiple goroutines.<\/span>\n<\/span><\/span>type<\/span> Source<\/span> interface<\/span> {<\/span>\n<\/span><\/span>\tInt63<\/span>()<\/span> int64<\/span>\n<\/span><\/span>\tSeed<\/span>(<\/span>seed<\/span> int64<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u4ece newSource \u4e2d\uff0c\u53ef\u4ee5\u770b\u5230\u8c03\u7528\u4e86 rng.Seed(seed)<\/code> \uff0c\u5373 rngSource \u7684 Seed \uff0c\u8fd9\u4e2a\u5c31\u662f\u968f\u673a\u5668\u521d\u59cb\u5316\u7684\u6838\u5fc3\u51fd\u6570\u3002<\/font><\/u><\/p>\n
      \n  \ud83e\udef5\ud83d\ude0e<\/summary>\n  
      const<\/span> (<\/span>\n<\/span><\/span>\trngLen<\/span>   =<\/span> 607<\/span>\n<\/span><\/span>\trngTap<\/span>   =<\/span> 273<\/span>\n<\/span><\/span>\trngMax<\/span>   =<\/span> 1<\/span> <<<\/span> 63<\/span>\n<\/span><\/span>\trngMask<\/span>  =<\/span> rngMax<\/span> -<\/span> 1<\/span>\n<\/span><\/span>\tint32max<\/span> =<\/span> (<\/span>1<\/span> <<<\/span> 31<\/span>)<\/span> -<\/span> 1<\/span>\n<\/span><\/span>)<\/span>\n<\/span><\/span>\n<\/span><\/span>\/\/ Seed uses the provided seed value to initialize the generator to a deterministic state.<\/span>\n<\/span><\/span>func<\/span> (<\/span>rng<\/span> *<\/span>rngSource<\/span>)<\/span> Seed<\/span>(<\/span>seed<\/span> int64<\/span>)<\/span> {<\/span>\n<\/span><\/span>\trng<\/span>.<\/span>tap<\/span> =<\/span> 0<\/span>\n<\/span><\/span>\trng<\/span>.<\/span>feed<\/span> =<\/span> rngLen<\/span> -<\/span> rngTap<\/span>\n<\/span><\/span>\n<\/span><\/span>\tseed<\/span> =<\/span> seed<\/span> %<\/span> int32max<\/span>\n<\/span><\/span>\tif<\/span> seed<\/span> <<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\tseed<\/span> +=<\/span> int32max<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\tif<\/span> seed<\/span> ==<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\tseed<\/span> =<\/span> 89482311<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\n<\/span><\/span>\tx<\/span> :=<\/span> int32<\/span>(<\/span>seed<\/span>)<\/span>\n<\/span><\/span>\tfor<\/span> i<\/span> :=<\/span> -<\/span>20<\/span>;<\/span> i<\/span> <<\/span> rngLen<\/span>;<\/span> i<\/span>++<\/span> {<\/span>\n<\/span><\/span>\t\tx<\/span> =<\/span> seedrand<\/span>(<\/span>x<\/span>)<\/span>\n<\/span><\/span>\t\tif<\/span> i<\/span> >=<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\t\tvar<\/span> u<\/span> int64<\/span>\n<\/span><\/span>\t\t\tu<\/span> =<\/span> int64<\/span>(<\/span>x<\/span>)<\/span> <<<\/span> 40<\/span>\n<\/span><\/span>\t\t\tx<\/span> =<\/span> seedrand<\/span>(<\/span>x<\/span>)<\/span>\n<\/span><\/span>\t\t\tu<\/span> ^=<\/span> int64<\/span>(<\/span>x<\/span>)<\/span> <<<\/span> 20<\/span>\n<\/span><\/span>\t\t\tx<\/span> =<\/span> seedrand<\/span>(<\/span>x<\/span>)<\/span>\n<\/span><\/span>\t\t\tu<\/span> ^=<\/span> int64<\/span>(<\/span>x<\/span>)<\/span>\n<\/span><\/span>\t\t\tu<\/span> ^=<\/span> rngCooked<\/span>[<\/span>i<\/span>]<\/span>\n<\/span><\/span>\t\t\trng<\/span>.<\/span>vec<\/span>[<\/span>i<\/span>]<\/span> =<\/span> u<\/span>\n<\/span><\/span>\t\t}<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span>\n<\/span><\/span>\n<\/span><\/span>\/\/ seed rng x[n+1] = 48271 * x[n] mod (2**31 - 1)<\/span>\n<\/span><\/span>func<\/span> seedrand<\/span>(<\/span>x<\/span> int32<\/span>)<\/span> int32<\/span> {<\/span>\n<\/span><\/span>\tconst<\/span> (<\/span>\n<\/span><\/span>\t\tA<\/span> =<\/span> 48271<\/span>\n<\/span><\/span>\t\tQ<\/span> =<\/span> 44488<\/span>\n<\/span><\/span>\t\tR<\/span> =<\/span> 3399<\/span>\n<\/span><\/span>\t)<\/span>\n<\/span><\/span>\n<\/span><\/span>\thi<\/span> :=<\/span> x<\/span> \/<\/span> Q<\/span>\n<\/span><\/span>\tlo<\/span> :=<\/span> x<\/span> %<\/span> Q<\/span>\n<\/span><\/span>\tx<\/span> =<\/span> A<\/span>*<\/span>lo<\/span> -<\/span> R<\/span>*<\/span>hi<\/span>\n<\/span><\/span>\tif<\/span> x<\/span> <<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\tx<\/span> +=<\/span> int32max<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\treturn<\/span> x<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>\n<\/details>\n
      \u901a\u8fc7\u903b\u8f91\u53ef\u4ee5\u770b\u51fa\uff0c\u8c03\u7528 rand.Seed<\/strong> \u6765\u8bbe\u7f6e\u79cd\u5b50, \u5176\u5b9e\u5c31\u662f\u7ed9 rng.vec<\/strong> \u7684 607<\/strong> \u4e2a\u69fd\u8bbe\u7f6e\u5bf9\u5e94\u7684\u503c\u3002\u901a\u8fc7\u4e0a\u9762\u7684\u6e90\u7801\u90a3\u53ef\u4ee5\u770b\u51fa\u6765, rand.Seed<\/strong> \u4f1a\u8c03\u7528\u4e00\u4e2a seedrand<\/strong> \u7684\u51fd\u6570, \u6765\u8ba1\u7b97\u5bf9\u5e94\u69fd\u7684\u503c\u3002\u8fd9\u4e2a\u51fd\u6570\u7684\u8ba1\u7b97\u7ed3\u679c\u5e76\u4e0d\u662f\u968f\u673a\u7684\uff0c\u800c\u662f\u6839\u636e seed \u5b9e\u9645\u7b97\u51fa\u6765\u7684\uff0c\u53e6\u5916\u8fd9\u4e2a\u51fd\u6570\u5e76\u4e0d\u662f\u968f\u4fbf\u5199\u7684\uff0c\u662f\u6709\u76f8\u5173\u7684\u6570\u5b66\u8bc1\u660e\u7684\u3002\n\u8fd9\u4e5f\u5bfc\u81f4\u4e86\u76f8\u540c\u7684 seed\uff0c\u6700\u7ec8\u8bbe\u7f6e\u5230 rng.vec<\/strong> \u91cc\u9762\u7684\u503c\u662f\u76f8\u540c\u7684\u3002\n\u603b\u7ed3\u4e0b\uff0c\u968f\u673a\u5668\u521d\u59cb\u5316\u7684\u903b\u8f91\u5176\u5b9e\u5c31\u662f\u4e3a\u4e86\u8fdb\u884c rng.tap<\/strong>\u3001rng.feed<\/strong>\u3001 rng.vec<\/strong> \u7684\u521d\u59cb\u5316\u5de5\u4f5c\u3002\n\u5176\u4e2d\uff0c\u9700\u8981\u7279\u522b\u6ce8\u610f\u7684\u662f\uff1a\n\u76f8\u540c\u7684seed\u79cd\u5b50<\/strong> \u6216\u8005 seed\u79cd\u5b50\u53d6\u6a21int32\u6700\u5927\u503c\u540e\u76f8\u7b49<\/strong>\uff1b\n\u8fd9\u4e24\u79cd\u60c5\u51b5\u90fd\u4f1a\u5bfc\u81f4\u6700\u7ec8\u8bbe\u7f6e\u5230 rng.vec \u91cc\u9762\u7684\u503c\u662f\u76f8\u540c\u7684\u3002<\/p>\n
      \n
      \u4ee5\u4e0a\u5c31\u662f\u968f\u673a\u5668\u521d\u59cb\u5316\uff0c\u63a5\u4e0b\u6765\u770b\u4e0b\u968f\u673a\u6570\u662f\u5982\u4f55\u4ea7\u751f\u7684\u3002\n\u4ecer.Intn(314)<\/code> \u5f00\u59cb\u89e3\u6790\u3002<\/strong>\n\u4ee5 rand.Intn()<\/code> \u4e3a\u4f8b\uff0c\u770b\u4e0b\u5177\u4f53\u7684\u5b9e\u73b0\u3002<\/p>\n
      \/\/ Intn returns, as an int, a non-negative pseudo-random number in the half-open interval [0,n).<\/span>\n<\/span><\/span>\/\/ It panics if n <= 0.<\/span>\n<\/span><\/span>func<\/span> (<\/span>r<\/span> *<\/span>Rand<\/span>)<\/span> Intn<\/span>(<\/span>n<\/span> int<\/span>)<\/span> int<\/span> {<\/span>\n<\/span><\/span>\tif<\/span> n<\/span> <=<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\tpanic<\/span>(<\/span>"invalid argument to Intn"<\/span>)<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\tif<\/span> n<\/span> <=<\/span> 1<\/span><<<\/span>31<\/span>-<\/span>1<\/span> {<\/span>\n<\/span><\/span>\t\treturn<\/span> int<\/span>(<\/span>r<\/span>.<\/span>Int31n<\/span>(<\/span>int32<\/span>(<\/span>n<\/span>)))<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\treturn<\/span> int<\/span>(<\/span>r<\/span>.<\/span>Int63n<\/span>(<\/span>int64<\/span>(<\/span>n<\/span>)))<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u67e5\u770b\u6e90\u7801\u53ef\u4e86\u89e3\u5230\uff0c\u5c0f\u4e8e\u7b49\u4e8e MaxInt32<\/code> \u7684\u503c\u8c03\u7528\u7684\u662f r.Int31n<\/code> \u3002<\/p>\n
      \/\/ Int31n returns, as an int32, a non-negative pseudo-random number in the half-open interval [0,n).<\/span>\n<\/span><\/span>\/\/ It panics if n <= 0.<\/span>\n<\/span><\/span>func<\/span> (<\/span>r<\/span> *<\/span>Rand<\/span>)<\/span> Int31n<\/span>(<\/span>n<\/span> int32<\/span>)<\/span> int32<\/span> {<\/span>\n<\/span><\/span>\tif<\/span> n<\/span> <=<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\tpanic<\/span>(<\/span>"invalid argument to Int31n"<\/span>)<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\tif<\/span> n<\/span>&<\/span>(<\/span>n<\/span>-<\/span>1<\/span>)<\/span> ==<\/span> 0<\/span> {<\/span> \/\/ n is power of two, can mask<\/span>\n<\/span><\/span>\t\treturn<\/span> r<\/span>.<\/span>Int31<\/span>()<\/span> &<\/span> (<\/span>n<\/span> -<\/span> 1<\/span>)<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\tmax<\/span> :=<\/span> int32<\/span>((<\/span>1<\/span> <<<\/span> 31<\/span>)<\/span> -<\/span> 1<\/span> -<\/span> (<\/span>1<\/span><<<\/span>31<\/span>)<\/span>%<\/span>uint32<\/span>(<\/span>n<\/span>))<\/span>\n<\/span><\/span>\tv<\/span> :=<\/span> r<\/span>.<\/span>Int31<\/span>()<\/span>\n<\/span><\/span>\tfor<\/span> v<\/span> ><\/span> max<\/span> {<\/span>\n<\/span><\/span>\t\tv<\/span> =<\/span> r<\/span>.<\/span>Int31<\/span>()<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\treturn<\/span> v<\/span> %<\/span> n<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u5982\u679c\u4f20\u5165\u7684\u503c\u662f2\u7684\u5e42\u6b21\u65b9\uff0c\u5219\u8c03\u7528\u7684 r.Int31() & (n - 1)<\/code> \uff1b<\/p>\n
      \u56e0\u4e3a\u4f20\u5165\u7684314\u4e0d\u662f2\u7684\u5e42\u6b21\u65b9\uff0c\u6240\u4ee5\u8d70\u7684\u662f max := int32((1 << 31) - 1 - (1<<31)%uint32(n))<\/code> \u4e0b\u9762\u7684\u903b\u8f91\u3002<\/p>\n
      \u9488\u5bf9 max \u8fd9\u4e2a\u903b\u8f91\uff0c\u9700\u8981\u7406\u89e3\u5b83\u7684\u7528\u9014\uff0c\u5b83\u5176\u5b9e\u662f\u5c06 int32<\/strong>  0, (1 << 31) - 1<\/code> \u8303\u56f4\u5185\u5c3e\u90e8\uff0c\u201c\u53d6\u6a21\u540e\u201d\uff0c\u4e0d\u80fd\u8986\u76d6  [0, n) <\/code> \u7684\u6570\u503c\u53bb\u6389\uff0c\u8fd9\u6837\u5c31\u4fdd\u8bc1\u4e86  [0, n) <\/code> \u5185\u5404\u4e2a\u6570\u503c\u51fa\u73b0\u7684\u6982\u7387\u662f\u4e00\u81f4\u7684\u3002\u4e3e\u4f8b\u5982\u4e0b\uff1a<\/p>\n
      var<\/span> n<\/span> int32<\/span> =<\/span> 314<\/span>\n<\/span><\/span>tail<\/span> :=<\/span> (<\/span>1<\/span> <<<\/span> 31<\/span>)<\/span> %<\/span> uint32<\/span>(<\/span>n<\/span>)<\/span>\n<\/span><\/span>max<\/span> :=<\/span> int32<\/span>((<\/span>1<\/span> <<<\/span> 31<\/span>)<\/span> -<\/span> 1<\/span> -<\/span> (<\/span>1<\/span><<<\/span>31<\/span>)<\/span>%<\/span>uint32<\/span>(<\/span>n<\/span>))<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>tail<\/span>)<\/span>    \/\/ 282<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>max<\/span>)<\/span>     \/\/ 2147483365<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>max<\/span> %<\/span> n<\/span>)<\/span> \/\/ 313<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u7ee7\u7eed\u5f80\u4e0b\u770b\u903b\u8f91\uff0c\u65e0\u8bba\u662f\u4e0d\u662f2\u7684\u5e42\u6b21\u65b9\uff0c\u6700\u7ec8\u90fd\u4f1a\u8c03\u7528\u5230   r.Int31() <\/code> \uff0c\u6240\u4ee5\u9700\u8981\u770b r.Int31() <\/code> \u7684\u5177\u4f53\u5b9e\u73b0\u3002<\/p>\n
      \/\/ Int31 returns a non-negative pseudo-random 31-bit integer as an int32.<\/span>\n<\/span><\/span>func<\/span> (<\/span>r<\/span> *<\/span>Rand<\/span>)<\/span> Int31<\/span>()<\/span> int32<\/span> {<\/span> return<\/span> int32<\/span>(<\/span>r<\/span>.<\/span>Int63<\/span>()<\/span> >><\/span> 32<\/span>)<\/span> }<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      r.Int31() <\/code>  \u4e2d\u8c03\u7528\u7684\u662f   r.Int63() <\/code> \uff0c\u7136\u540e\u53d6\u7ed3\u679c\u7684\u9ad831\u4f4d\u4f5c\u4e3a int32<\/strong> \u968f\u673a\u503c\uff0c\u4e0b\u9762\u770b r.Int63() <\/code> \u7684\u5b9e\u73b0\u3002<\/p>\n
      \/\/ Int63 returns a non-negative pseudo-random 63-bit integer as an int64.<\/span>\n<\/span><\/span>func<\/span> (<\/span>r<\/span> *<\/span>Rand<\/span>)<\/span> Int63<\/span>()<\/span> int64<\/span> {<\/span> return<\/span> r<\/span>.<\/span>src<\/span>.<\/span>Int63<\/span>()<\/span> }<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u53ef\u4ee5\u770b\u5230\uff0c\u6700\u7ec8\u8c03\u7528\u7684\u662f r.src.Int63()<\/code> \u3002<\/p>\n
      \u770b\u4e0bRand\u7684\u5b9a\u4e49\uff0c\u56e0\u4e3a\u4e0a\u9762\u5df2\u7ecf\u5206\u6790\u51fa\u4e86Rand\u7684src\u7684\u5177\u4f53\u5b9e\u73b0\u5c31\u662f rngSource<\/strong>\u3002<\/p>\n
      \/\/ A Rand is a source of random numbers.<\/span>\n<\/span><\/span>type<\/span> Rand<\/span> struct<\/span> {<\/span>\n<\/span><\/span>\tsrc<\/span> Source<\/span>\n<\/span><\/span>\ts64<\/span> Source64<\/span> \/\/ non-nil if src is source64<\/span>\n<\/span><\/span>\n<\/span><\/span>\t\/\/ readVal contains remainder of 63-bit integer used for bytes<\/span>\n<\/span><\/span>\t\/\/ generation during most recent Read call.<\/span>\n<\/span><\/span>\t\/\/ It is saved so next Read call can start where the previous<\/span>\n<\/span><\/span>\t\/\/ one finished.<\/span>\n<\/span><\/span>\treadVal<\/span> int64<\/span>\n<\/span><\/span>\t\/\/ readPos indicates the number of low-order bytes of readVal<\/span>\n<\/span><\/span>\t\/\/ that are still valid.<\/span>\n<\/span><\/span>\treadPos<\/span> int8<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u56e0\u6b64\uff0c\u968f\u673a\u6570\u7684\u4ea7\u751f\u8c03\u7528\u7684\u5c31\u662f rngSource<\/strong> \u7ed3\u6784\u4f53\u7684 Int63<\/strong> \u51fd\u6570\u3002<\/p>\n
      \/\/ Int63 returns a non-negative pseudo-random 63-bit integer as an int64.<\/span>\n<\/span><\/span>func<\/span> (<\/span>rng<\/span> *<\/span>rngSource<\/span>)<\/span> Int63<\/span>()<\/span> int64<\/span> {<\/span>\n<\/span><\/span>\treturn<\/span> int64<\/span>(<\/span>rng<\/span>.<\/span>Uint64<\/span>()<\/span> &<\/span> rngMask<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u5176\u4e2d rngMask<\/strong> \u8868\u793a Int64 \u7684\u6700\u5927\u503c\uff0c\u4f5c\u7528\u662f\u4f5c\u4e3a\u63a9\u7801\u3002<\/p>\n
      rngMax<\/span>   =<\/span> 1<\/span> <<<\/span> 63<\/span>\n<\/span><\/span>rngMask<\/span>  =<\/span> rngMax<\/span> -<\/span> 1<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u800c  rng.Uint64()<\/code> \uff0c\u5219\u662f\u4ea7\u751f\u968f\u673a\u6570\u7684\u6838\u5fc3\u51fd\u6570\uff1b\u5b83\u7684\u6838\u5fc3\u903b\u8f91\u5c31\u662f\u4ece\u6570\u7ec4 rngSource.vec<\/code> \u4e2d\u53d6\u51fa\u968f\u673a\u6570\u3002<\/font><\/u><\/p>\n
      \/\/ Uint64 returns a non-negative pseudo-random 64-bit integer as an uint64.<\/span>\n<\/span><\/span>func<\/span> (<\/span>rng<\/span> *<\/span>rngSource<\/span>)<\/span> Uint64<\/span>()<\/span> uint64<\/span> {<\/span>\n<\/span><\/span>\trng<\/span>.<\/span>tap<\/span>--<\/span>\n<\/span><\/span>\tif<\/span> rng<\/span>.<\/span>tap<\/span> <<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\trng<\/span>.<\/span>tap<\/span> +=<\/span> rngLen<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\n<\/span><\/span>\trng<\/span>.<\/span>feed<\/span>--<\/span>\n<\/span><\/span>\tif<\/span> rng<\/span>.<\/span>feed<\/span> <<\/span> 0<\/span> {<\/span>\n<\/span><\/span>\t\trng<\/span>.<\/span>feed<\/span> +=<\/span> rngLen<\/span>\n<\/span><\/span>\t}<\/span>\n<\/span><\/span>\n<\/span><\/span>\tx<\/span> :=<\/span> rng<\/span>.<\/span>vec<\/span>[<\/span>rng<\/span>.<\/span>feed<\/span>]<\/span> +<\/span> rng<\/span>.<\/span>vec<\/span>[<\/span>rng<\/span>.<\/span>tap<\/span>]<\/span>\n<\/span><\/span>\trng<\/span>.<\/span>vec<\/span>[<\/span>rng<\/span>.<\/span>feed<\/span>]<\/span> =<\/span> x<\/span>\n<\/span><\/span>\treturn<\/span> uint64<\/span>(<\/span>x<\/span>)<\/span>\n<\/span><\/span>}<\/span>\n<\/span><\/span><\/code><\/pre><\/div>
      \u5b9e\u9645\u4e0a\uff0c\u8c03\u7528 Intn(), Int31n(), Int63(), Int63n()<\/code> \u7b49\u5176\u4ed6\u968f\u673a\u51fd\u6570\uff0c\u6700\u7ec8\u8c03\u7528\u5230\u90fd\u662f\u51fd\u6570 rngSource.Uint64()<\/code> \u3002\u53ef\u4ee5\u770b\u5230\u6bcf\u6b21\u8c03\u7528\u5c31\u662f\u5229\u7528 rng.feed, rng.tap \u4ece rng.vec \u4e2d\u53d6\u5230\u4e24\u4e2a\u503c\u76f8\u52a0\u7684\u7ed3\u679c\u8fd4\u56de\uff0c\u540c\u65f6\u8fd9\u4e2a\u7ed3\u679c\u53c8\u91cd\u65b0\u653e\u5165 rng.vec<\/strong>\u3002\u8fd9\u6837\u505a\u7684\u76ee\u7684\u662f\uff0c\u8ba9\u968f\u673a\u6570\u66f4\u52a0\u4e30\u5bcc\u968f\u673a\uff0c\u800c\u4e0d\u662f\u4ec5\u5c40\u9650\u4e8e rng.vec \u6570\u7ec4\u4e2d\u7684\u503c\u3002<\/p>\n
      \u6e90\u7801\u603b\u7ed3\n<\/h2>
      \u901a\u8fc7\u4ee5\u4e0a\u7684\u6e90\u7801\u5206\u6790\uff0c\u53ef\u4ee5\u603b\u7ed3\u51fa\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n
        \n
      1. rand.New \u521d\u59cb\u5316\u51fa\u6765\u7684 rand \u4e0d\u662f\u5e76\u53d1\u5b89\u5168\u7684\u3002<\/strong> \u56e0\u4e3a\u6bcf\u6b21\u5229\u7528 rng.feed, rng.tap \u4ece rng.vec \u4e2d\u53d6\u5230\u968f\u673a\u503c\u540e\u4f1a\u5c06\u968f\u673a\u503c\u91cd\u65b0\u653e\u5165 rng.vec\uff0c\u5f53\u591a goroutine \u540c\u65f6\u8c03\u7528\u65f6\u5c31\u4f1a\u6709\u6570\u636e\u7ade\u4e89\u95ee\u9898\u3002\u5982\u679c\u60f3\u5e76\u53d1\u5b89\u5168\uff0c\u53ef\u4ee5\u4f7f\u7528\u5168\u5c40\u7684\u968f\u673a\u6570\u53d1\u751f\u5668 rand.globalRand\uff0c\u5b83\u662f\u57fa\u4e8elockedSource\u5b9e\u73b0\u7684\uff0c\u8fdb\u884c\u4e86\u52a0\u9501\u7684\u903b\u8f91\u3002<\/li>\n
      2. \u76f8\u540cseed\u79cd\u5b50\uff0c\u6bcf\u6b21\u8fd0\u884c\u7684\u7ed3\u679c\u662f\u4e00\u6837\u7684\u3002<\/strong> \u56e0\u4e3a\u968f\u673a\u6570\u662f\u4ece rng.vec \u6570\u7ec4\u4e2d\u53d6\u51fa\u6765\u7684\uff0c\u8fd9\u4e2a\u6570\u7ec4\u662f\u6839\u636e\u79cd\u5b50\u751f\u6210\u7684\uff0c\u76f8\u540c\u7684\u79cd\u5b50\u751f\u6210\u7684 rng.vec \u6570\u7ec4\u662f\u76f8\u540c\u7684\u3002<\/li>\n
      3. \u4e0d\u540cseed\u79cd\u5b50\uff0c\u6bcf\u6b21\u8fd0\u884c\u7684\u7ed3\u679c\u53ef\u80fd\u4e00\u6837\u3002<\/strong> \u56e0\u4e3a\u6839\u636e\u79cd\u5b50\u751f\u6210 rng.vec \u6570\u7ec4\u65f6\u4f1a\u6709\u4e00\u4e2a\u5bf9int32\u6700\u5927\u503c\u53d6\u6a21\u7684\u64cd\u4f5c\uff0c\u6a21\u540e\u7684\u7ed3\u679c\u53ef\u80fd\u76f8\u540c\uff0c\u4e5f\u5c31\u662f\u4e24\u4e2a\u79cd\u5b50\u5982\u679c\u76f8\u5deeint32\u7684\u6700\u5927\u503c\uff0c\u5c31\u4f1a\u5bfc\u81f4 rng.vec \u6570\u7ec4\u76f8\u540c\u3002<\/li>\n<\/ol>\n
        r1<\/span> :=<\/span> rand<\/span>.<\/span>New<\/span>(<\/span>rand<\/span>.<\/span>NewSource<\/span>(<\/span>1111<\/span>))<\/span>\n<\/span><\/span>r2<\/span> :=<\/span> rand<\/span>.<\/span>New<\/span>(<\/span>rand<\/span>.<\/span>NewSource<\/span>(<\/span>1111<\/span> +<\/span> math<\/span>.<\/span>MaxInt32<\/span>))<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>"\u7b2c\u4e00\u4e2a\u968f\u673a\u5668\uff1a"<\/span>,<\/span> r1<\/span>.<\/span>Intn<\/span>(<\/span>10000<\/span>))<\/span>  \/\/ \u7b2c\u4e00\u4e2a\u968f\u673a\u5668\uff1a 9241<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>"\u7b2c\u4e00\u4e2a\u968f\u673a\u5668\uff1a"<\/span>,<\/span> r1<\/span>.<\/span>Intn<\/span>(<\/span>10000<\/span>))<\/span>  \/\/ \u7b2c\u4e00\u4e2a\u968f\u673a\u5668\uff1a 8842<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>"\u7b2c\u4e00\u4e2a\u968f\u673a\u5668\uff1a"<\/span>,<\/span> r1<\/span>.<\/span>Intn<\/span>(<\/span>10000<\/span>))<\/span>  \/\/ \u7b2c\u4e00\u4e2a\u968f\u673a\u5668\uff1a 2221<\/span>\n<\/span><\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>"\u7b2c\u4e8c\u4e2a\u968f\u673a\u5668\uff1a"<\/span>,<\/span> r2<\/span>.<\/span>Intn<\/span>(<\/span>10000<\/span>))<\/span>  \/\/ \u7b2c\u4e8c\u4e2a\u968f\u673a\u5668\uff1a 9241<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>"\u7b2c\u4e8c\u4e2a\u968f\u673a\u5668\uff1a"<\/span>,<\/span> r2<\/span>.<\/span>Intn<\/span>(<\/span>10000<\/span>))<\/span>  \/\/ \u7b2c\u4e8c\u4e2a\u968f\u673a\u5668\uff1a 8842<\/span>\n<\/span><\/span>fmt<\/span>.<\/span>Println<\/span>(<\/span>"\u7b2c\u4e8c\u4e2a\u968f\u673a\u5668\uff1a"<\/span>,<\/span> r2<\/span>.<\/span>Intn<\/span>(<\/span>10000<\/span>))<\/span>  \/\/ \u7b2c\u4e8c\u4e2a\u968f\u673a\u5668\uff1a 2221<\/span>\n<\/span><\/span><\/code><\/pre><\/div>"},{"title":"\u5f52\u6863","link":"https:\/\/hcraM41.github.io\/archives\/","pubDate":"Tue, 28 May 2019 00:00:00 +0000","guid":"https:\/\/hcraM41.github.io\/archives\/","description":{}},{"title":"\u5173\u4e8e","link":"https:\/\/hcraM41.github.io\/%E5%85%B3%E4%BA%8E\/","pubDate":"Mon, 01 Jan 0001 00:00:00 +0000","guid":"https:\/\/hcraM41.github.io\/%E5%85%B3%E4%BA%8E\/","description":"
        This is a test page for i18n support.<\/p>\n"},{"title":"\u641c\u7d22","link":"https:\/\/hcraM41.github.io\/search\/","pubDate":"Mon, 01 Jan 0001 00:00:00 +0000","guid":"https:\/\/hcraM41.github.io\/search\/","description":{}},{"title":"\u53cb\u60c5\u94fe\u63a5","link":"https:\/\/hcraM41.github.io\/%E5%8F%8B%E6%83%85%E9%93%BE%E6%8E%A5\/","pubDate":"Mon, 01 Jan 0001 00:00:00 +0000","guid":"https:\/\/hcraM41.github.io\/%E5%8F%8B%E6%83%85%E9%93%BE%E6%8E%A5\/","description":{}}]}}