{"id":125616,"date":"2020-06-24T07:47:25","date_gmt":"2020-06-23T23:47:25","guid":{"rendered":"http:\/\/4563.org\/?p=125616"},"modified":"2020-06-24T07:47:25","modified_gmt":"2020-06-23T23:47:25","slug":"%e5%a4%a7%e5%ae%b6%e5%86%99-golang-%e7%9a%84%e6%97%b6%e5%80%99%e6%98%af%e5%90%a6%e5%a4%84%e7%90%86-f-close-%e8%bf%94%e5%9b%9e%e7%9a%84%e9%94%99%e8%af%af%e5%80%bc%ef%bc%9f","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=125616","title":{"rendered":"\u5927\u5bb6\u5199 golang \u7684\u65f6\u5019\u662f\u5426\u5904\u7406 f.Close \u8fd4\u56de\u7684\u9519\u8bef\u503c\uff1f"},"content":{"rendered":"<div>\n<div>\n<div>\n<h1>                  \u5927\u5bb6\u5199 golang \u7684\u65f6\u5019\u662f\u5426\u5904\u7406 f.Close \u8fd4\u56de\u7684\u9519\u8bef\u503c\uff1f               <\/h1>\n<p> <\/p>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : SimbaPeng <\/span>  <span><i><\/i> 5<\/span> <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div isfirst=\"1\"> <\/p>\n<p>golang \u91cc\u6253\u5f00\u67d0\u4e2a\u8d44\u6e90\uff0c\u901a\u5e38\u90fd\u4f1a\u5728\u4e0b\u9762\u7d27\u63a5\u7740 defer f.Close, \u8fd9\u4e2a f \u662f\u6307\u4efb\u4f55\u9700\u8981 close \u7684\u8d44\u6e90\uff0c\u6ca1\u6709\u7279\u6307\u6587\u4ef6\u3002<\/p>\n<p>\u4f46\u662f close \u65b9\u6cd5\u90fd\u4f1a\u8fd4\u56de\u4e00\u4e2a err\uff0c\u5927\u5bb6\u5728\u5b9e\u9645\u7f16\u7801\u4e2d\u4f1a\u53bb\u5904\u7406\u8fd9\u4e2a err \u5417\uff0c\u5982\u679c\u5904\u7406\uff0c\u600e\u4e48\u5904\u7406\u5462\uff1f<\/p>\n<p>\u8bb0\u5f55\u65e5\u5fd7\u4e4b\u540e os.Exit() or panic ?<\/p>\n<p>\u8fd9 2 \u4e2a\u6211\u611f\u89c9\u90fd\u4e0d\u597d\u7528\u554a\uff0cos.Exit()\u4f1a\u8df3\u8fc7 defer \u76f4\u63a5\u7ec8\u6b62\u7a0b\u5e8f\uff0c\u4e5f\u5c31\u662f\u8bf4\u5982\u679c\u7a0b\u5e8f\u4e2d\u8fd8\u6709\u5176\u4ed6\u8d44\u6e90\u5728 defer \u91cc\u6e05\u7406\uff0c\u90fd\u4f1a\u5931\u6548\u3002<\/p>\n<p>\u800c panic \u53ea\u4f1a\u6267\u884c\u5f53\u524d goroutine \u7684 defer, \u7136\u540e\u7a0b\u5e8f\u5d29\u6e83\u9000\u51fa\uff0c\u5982\u679c\u7a0b\u5e8f\u5728\u591a\u4e2a goroutine \u4e2d\u90fd\u6709 defer \u8981\u6267\u884c\uff0c\u90a3\u4e48\u5176\u4ed6 goroutine \u7684 defer \u90fd\u4e0d\u80fd\u4fdd\u8bc1\u6267\u884c\u4e86\u3002\u96be\u9053\u6211\u8981\u5728\u6bcf\u4e2a goroutine \u90fd\u6355\u83b7 panic \u6765\u4fdd\u8bc1\u7a0b\u5e8f\u4e0d\u5d29\u6e83\u5417\uff1f\uff1f<\/p>\n<p>golang \u91cc\u5c31\u6ca1\u6709 finally \u8fd9\u79cd\u53ea\u8981\u8fdb\u4e86 try \u5757\u5c31\u603b\u4f1a\u6267\u884c\u7684\u673a\u5236\u5417\uff1f\uff1f<\/p>\n<\/p><\/div>\n<div> <b>\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (<span>17<\/span>)        <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<ul>\n<li data-pid=\"2155100\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : xmge <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u611f\u89c9\u95ee\u9898\u6709\u70b9\u4e71\uff0c\u6574\u7406\u4e00\u4e0b\uff1a<\/p>\n<p>1. defer f.Close \u7684 error \u5904\u7406\u5417\uff1f\u5982\u4f55\u5904\u7406?<br \/>2.\u662f\u4e0d\u662f\u6bcf\u4e2a goroutine \u4e2d\u90fd\u8981\u5199 defer {err := recover } \u6765\u6355\u6349\u5f02\u5e38\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155101\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : reus <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u4e00\u822c\u4e0d\u5904\u7406\uff0c\u5982\u679c\u975e\u8981\u5904\u7406\u7684\u8bdd\uff0c\u8fd9\u6837\u5199<\/p>\n<p>https:\/\/gist.github.com\/reusee\/25836c8a6faac925fe52c1c73d122a04 <button onclick=\"lazyGist(this)\">\u00a0\u663e\u793a Gist \u4ee3\u7801\u00a0<\/button> <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155102\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : lewinlan <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u6253\u5f00\u7684\u8d44\u6e90\u7c7b\u578b\u4e0d\u540c\uff0cerr \u7684\u5f71\u54cd\u80af\u5b9a\u4e5f\u4e0d\u540c\u3002\u81ea\u5df1\u770b\u6e90\u7801\u6ce8\u91ca\u51b3\u5b9a\u3002                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155103\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : Aoang <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u8fd9\u6bb5\u65f6\u95f4\u7528\u4e86\u4e00\u4e2a\u4e09\u65b9\u5e93\uff0c\u5e93\u91cc\u9762\u5230\u5904\u90fd\u662f panic \u90a3\u79cd\uff0c\u5b83\u5c31\u662f\u5c5e\u4e8e\u4ec0\u4e48 error \u90fd\u4f1a\u5904\u7406\u7684\u3002<\/p>\n<p>\u6211\u7528\u8fd9\u4e2a\u5e93\u7684\u65f6\u5019\uff0c\u6ca1\u6709\u4efb\u4f55\u611f\u53d7\u2026\uff08<\/p>\n<p>\u4e0d\u5199 recover \u7684\u8bdd\uff0c\u4e00\u8dd1\u5c31 panic\uff0c\u6ca1\u6709\u4e00\u4e2a\u5b8c\u5584\u7684\u9519\u8bef\u5904\u7406\u673a\u5236\uff0c\u4e0d\u7ed9\u8c03\u7528\u8005\u5904\u7406\u7684\u673a\u4f1a\u3002                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155104\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : sagaxu <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u628a\u4e00\u4e2a exception \u641e\u6210\u8fd9\u6837\u4e5f\u662f\u5927\u9053\u81f3\u7b80\u4e48                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155105\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : virusdefender <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u4e00\u822c close \u5931\u8d25\u4e86\u4e5f\u6ca1\u5565\u8865\u6551\u7684\u529e\u6cd5\uff0c\u6253\u5370\u65e5\u5fd7\u610f\u4e49\u4e5f\u4e0d\u5927\uff0c\u6211\u9009\u62e9\u76f4\u63a5 defer \u5ffd\u7565                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155106\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : input2output <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             https:\/\/www.joeshaw.org\/dont-defer-close-on-writable-files\/                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155107\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : fengjianxinghun <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u5927\u9053\u81f3\u7b80\u8fd8\u6015\u8fd9\u79cd\u95ee\u9898\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155108\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : Mohanson <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             close \u662f\u4e00\u4e2a\u7cfb\u7edf\u8c03\u7528, \u5b83\u51fa\u9519\u7684\u60c5\u51b5\u53ea\u6709: <\/p>\n<p>&#8220;`<br \/>ERRORS<br \/> The close() system call will fail if:<br \/> [EBADF] fildes is not a valid, active file descriptor.<br \/> [EINTR] Its execution was interrupted by a signal.<br \/> [EIO] A previously-uncommitted write(2) encountered an input\/output<br \/> error.<br \/>&#8220;`<\/p>\n<p>\u7a0b\u5e8f\u4e2d\u7ecf\u5e38\u9047\u5230\u7684\u662f EIO, \u4e5f\u5c31\u662f\u5728\u5728 close \u4e4b\u524d, read\/write \u5df2\u7ecf\u62a5\u9519\u4e86(\u6bd4\u5982\u6587\u4ef6 fd \u5df2\u7ecf\u63d0\u524d\u5173\u95ed, \u7f51\u7edc\u7684\u8bdd TCP \u8fde\u63a5\u5df2\u7ecf\u65ad\u5f00\u7b49), \u8fd9\u79cd\u60c5\u51b5\u5ffd\u7565 close \u7684 err \u624d\u662f\u6b63\u786e\u7684\u903b\u8f91. **\u56e0\u4e3a\u8c03\u7528 close \u7684\u6838\u5fc3\u76ee\u7684\u662f\u91ca\u653e\u8d44\u6e90, \u800c\u4e0d\u7ba1\u5728\u8fd9\u6b21\u8c03\u7528\u4e4b\u524d\u8d44\u6e90\u662f\u5426\u5df2\u7ecf\u88ab\u91ca\u653e\u4e86, \u7a0b\u5e8f\u53ea\u4fdd\u8bc1\u5728\u8be5\u6b21\u8c03\u7528 close \u540e\u8d44\u6e90\u4e00\u5b9a\u662f\u5df2\u7ecf\u91ca\u653e\u7684\u72b6\u6001\u5373\u53ef.**                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155109\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : reus <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u626f\u201c\u5927\u9053\u81f3\u7b80\u201d\u7684\u50bb\u903c\uff0c\u80fd\u4e0d\u80fd\u4e0d\u61c2\u5c31\u95ed\u5634\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155110\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : xmge <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             &#8220;`<br \/> f, err := os.Create(fn)<br \/> if err != nil {<br \/> return err<br \/> }<br \/> defer f.Close()<br \/>&#8220;`<\/p>\n<p>\u5728\u5b98\u65b9\u5e93\u4e2d\u4e5f\u662f\u8fd9\u4e48\u5199\u7684\uff0c\u5e94\u8be5\u5982\u4e0a\u6240\u8a00\uff0c\u8fd9\u4e2a error \u4e0d\u7528\u7ba1                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155111\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : lcode <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u53ef\u4ee5\u4e0d\u5904\u7406\uff0c\u4e00\u822c\u7684 lint \u5de5\u5177\u4e5f\u4f1a\u6709 ignore defer \u7c7b\u4f3c\u7684\u9009\u9879<br \/>\u5982\u679c\u975e\u8981\u5904\u7406\uff0c\u53ef\u4ee5<br \/>1. \u5c06\u9519\u8bef\u8fd4\u56de\uff0c\u4f46\u662f\u6ce8\u610f\u8fd9\u91cc\u5982\u679c\u8fd4\u56de\u7684\u8bdd\u53ef\u80fd\u4f1a\u8986\u76d6\u4ee3\u7801\u4e4b\u524d\u7684\u903b\u8f91\u4e2d\u7684\u9519\u8bef\uff0c\u6240\u4ee5\u6700\u597d\u7ec4\u5408\u5230\u4e00\u8d77\u8fd4\u56de<br \/>2. \u8fd4\u56de\u9519\u8bef\u65f6\u6253\u5370\u65e5\u5fd7\uff0c\u6216\u76f4\u63a5\u5c06\u5b9a\u4e49\u4e00\u4e2a log.CallFailed(func ())\u7c7b\u4f3c\u7684\u51fd\u6570\uff0c\u540e\u671f\u8fd0\u7ef4\u7684\u65f6\u5019\u53ef\u4ee5\u770b\u5230\u54ea\u91cc close \u65f6\u51fa\u9519\u4e86<br \/>3. \u6392\u9664\u6389\u5e94\u8be5\u8fd4\u56de\u9519\u8bef\u7684\u60c5\u51b5\u540e\uff0c\u76f4\u63a5 panic                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155112\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : hellodudu86 <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             1.err \u8981\u5904\u7406\u7684\u8bdd\u6700\u597d\u5c31\u662f\u8fd4\u56de\u7ed9\u4e0a\u5c42\u8c03\u7528\uff0c\u6709\u591a\u5c42\u4e0a\u62a5\u7684\u8bdd\u53ef\u4ee5\u89c6\u60c5\u51b5 wrap \u8fdb\u53bb\u5f53\u524d\u8c03\u7528\u5c42\u7684\u4fe1\u606f\uff0c\u4e0a\u5c42\u5224\u65ad\u7684\u65f6\u5019\u4f7f\u7528 errors.is()\u6765\u5904\u7406\uff0c\u8fd9\u6837\u5e95\u5c42\u7684\u4ee3\u7801\u90fd\u6bd4\u8f83\u7b80\u6d01\u4e14\u4e0d\u4f1a\u9677\u5165\u9762\u5bf9\u9519\u8bef\u7f16\u7a0b\u7684\u56f0\u5883\uff0c\u53ef\u4ee5\u53c2\u8003\u4e0b\u8fd9\u7bc7\u6587\u7ae0 https:\/\/blog.golang.org\/go1.13-errors                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155113\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : hellodudu86 <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             2.\u5f00\u65b0\u7684 goroutine \u4e00\u822c\u90fd\u4f1a\u5728 defer \u91cc\u9762 recover \u6765\u4fdd\u8bc1\u4e0d\u5d29\u6e83                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155114\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : CRVV <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             Java \u7684 finally \u4e5f\u4e0d\u4fdd\u8bc1\u80fd\u6267\u884c\u5230<br \/>https:\/\/stackoverflow.com\/questions\/1410951\/how-does-javas-system-exit-work-with-try-catch-finally-blocks<\/p>\n<p>\u4f46\u662f Python \u5728\u8fd9\u4e2a\u60c5\u51b5\u4e0b\u4f1a\u6267\u884c finally<\/p>\n<p>defer \u548c\u5176\u5b83\u8bed\u8a00\u91cc\u7684 finally \u57fa\u672c\u4e0a\u662f\u7b49\u4ef7\u7684\uff0c\u76f4\u63a5\u7528\u5c31\u662f\u4e86<\/p>\n<p>\u6211\u89c9\u5f97 panic \u548c os.Exit \u5728\u6b63\u5e38\u8fd0\u884c\u7684\u7a0b\u5e8f\u91cc\u4e0d\u591a\u89c1\uff0c\u51fa\u73b0\u4e86\u5c31\u9700\u8981\u6539 bug \u4e86\uff0c\u8fd9\u4e2a\u95ee\u9898\u4e5f\u6ca1\u591a\u5927\u5f71\u54cd                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155115\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : ujued <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u6709\u4e0d\u5f97\u4e0d\u5904\u7406\u7684\u65f6\u5019\uff0c\u7528\u533f\u540d\u51fd\u6570\uff1a<br \/>defer func(){<br \/> err := f.Close()<br \/> \/\/ Handle or Throw<br \/>}()                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li data-pid=\"2155116\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : dawniii <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             @input2output \u8fd9\u7bc7\u6587\u7ae0\u7684\u89c2\u70b9\u597d\u50cf\u662f\u4e0d\u5bf9\u7684\u3002\u8bf4\u662f close \u7684\u65f6\u5019\uff0c\u53ef\u80fd\u6709 buffer \u6ca1\u6709\u843d\u76d8\uff1f\u53ef\u662f go \u7684 write \u64cd\u4f5c\u6ca1\u6709\u5e94\u7528\u5c42 buffer \u7684\uff0c\u76f4\u63a5\u5c31\u662f write \u7cfb\u7edf\u8c03\u7528\u5199\u5230 page cache \u4e86\uff0c\u8fd9\u65f6\u5019\u5c31\u7b97\u8fdb\u7a0b\u6302\u4e86\uff0c\u5185\u6838\u4e5f\u5e94\u8be5\u4f1a\u81ea\u52a8\u843d\u76d8\u3002                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li>\n","protected":false},"excerpt":{"rendered":"<p>\u5927\u5bb6\u5199 golang \u7684\u65f6\u5019\u662f\u5426\u5904&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/125616"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=125616"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/125616\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=125616"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=125616"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=125616"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}