{"id":93613,"date":"2020-04-10T22:40:39","date_gmt":"2020-04-10T14:40:39","guid":{"rendered":"http:\/\/4563.org\/?p=93613"},"modified":"2020-04-10T22:40:39","modified_gmt":"2020-04-10T14:40:39","slug":"%e5%85%b3%e4%ba%8e-defer","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=93613","title":{"rendered":"\u5173\u4e8e defer"},"content":{"rendered":"
\n
\n
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\u5173\u4e8e defer <\/h1>\n

<\/p>\n

\n
\u8cc7\u6df1\u5927\u4f6c : lasuar <\/span> <\/i> 27<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
<\/p>\n

\u5e73\u65f6\u6ca1\u6ce8\u610f\uff0c\u4eca\u5929\u5076\u7136\u53d1\u73b0\u5b50\u534f\u7a0b panic \u540e\uff0c\u4e3b\u534f\u7a0b\u7684 defer \u5185\u7684\u64cd\u4f5c\u4e0d\u4f1a\u6267\u884c\uff1f\u8981\u8bf4\u6355\u6349\u4e0d\u5230\u5b50\u534f\u7a0b\u7684\u5f02\u5e38\u53ef\u4ee5\u7406\u89e3\uff0c\u8bf7\u95ee\u4e0b\u6709\u76f8\u5173\u7684\u6587\u6863\u8bf4\u660e\u8fd9\u4e2a\u73b0\u8c61\u7684\u5417\uff1f<\/p>\n

func Test_X(t *testing.T) {  defer log.Println(111)  go func() {   panic(222)  }() } <\/code><\/pre>\n
Out<\/p>\n
=== RUN   Test_X panic: 222 <\/code><\/pre>\n<\/p><\/div>\n
 \u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (21<\/span>)        <\/div>\n
 <\/div>\n<\/p><\/div>\n<\/p><\/div>\n
    \n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : Mohanson <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 panic \u540e\u9762\u52a0\u4e2a sleep\uff0c\u4f60\u5e94\u8be5\u80fd\u770b\u5230 111                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : lasuar <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @Mohanson \u4e0d\u884c\u7684\uff0c\u90fd\u8bd5\u8fc7                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : yoshiyuki <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4e3b\u534f\u7a0b\u5076\u5c14\u4f1a\u5148\u4e8e\u5b50\u534f\u7a0b\u7ed3\u675f\uff0c\u56e0\u4e3a\u534f\u7a0b\u7684\u8fd0\u884c\u662f\u5f02\u6b65\u7684\uff0c\u4e3b\u534f\u7a0b\u5e76\u4e0d\u4f1a\u53bb\u201d\u7b49\u5f85\u201c\u5b50\u534f\u7a0b\u7684\u8fd0\u884c\u7ed3\u675f<\/p>\n
    \u8981\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u4f7f\u7528 waitGroup \u6216\u8005 channel & … <\/p>\n
    note\uff1a\u8fd9\u4e0d\u662f\u4e00\u4e2a bug\uff0c\u800c\u662f\u534f\u7a0b\u4ee5\u53ca\u5f02\u6b65\u672c\u8eab\u7684\u7279\u6027                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : lasuar <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @yoshiyuki \u6211\u77e5\u9053\u8fd9\u4e0d\u662f bug \u3002\u4f60\u53ef\u4ee5\u7528\u4f60\u8bf4\u7684\u65b9\u5f0f\u8ba9\u4e3b\u534f\u7a0b\u7684 defer \u6267\u884c\uff0c\u5e76\u8d34\u51fa\u4f60\u7684\u4ee3\u7801\u3002                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : ClarkAbe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u5e94\u8be5\u662f\u9700\u8981\u7b49\u5f85\u72d7\u8089\u633a\u6267\u884c\u7ed3\u675f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : lasuar <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u8d34\u51fa\u4e00\u4e2a\u76f8\u540c\u8f93\u51fa\u7684\u7247\u6bb5\uff1a
    “`
    func Test_X(t *testing.T) {
     defer func() {
     log.Println(111)
     }()
     go func() {
     panic(222)
     }()
     time.Sleep(time.Second)
    }
    “`                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
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     \u8cc7\u6df1\u5927\u4f6c : thefack <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u591a\u8fd0\u884c\u51e0\u6b21\uff0c\u4f60\u5c31\u77e5\u9053 defer \u5230\u5e95\u6709\u6ca1\u6709\u6267\u884c\u8fc7                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
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     \u8cc7\u6df1\u5927\u4f6c : hallDrawnel <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4e0d\u4f1a\uff0cdefer \u5c31\u662f\u8fd9\u6837\u8bbe\u8ba1\u7684\uff0c\u53ea\u6709\u5728\u8c03\u7528 defer \u7684 goroutine \u4e2d panic \u624d\u4f1a\u6267\u884c\uff0c\u5176\u4ed6 goroutine \u6ca1\u6709\u63d0\u53ca\uff0c\u90a3\u4e48\u5c31\u662f\u6ca1\u6709\u4fdd\u8bc1\u3002
    \u6587\u6863\u5728 https:\/\/golang.org\/ref\/spec#Defer_statements<\/p>\n
    A “defer” statement invokes a function whose execution is deferred to the moment the surrounding function returns, either because the surrounding function executed a return statement, reached the end of its function body, or because the corresponding goroutine is panicking.<\/p>\n
    \u6587\u6863\u6307\u660e\u4e86\u5728\u201cthe corresponding goroutine\u201d panic \u7684\u65f6\u5019\u624d\u4f1a defer \u3002<\/p>\n
    \u4e3a\u4e86\u786e\u5b9a panic \u5728\u4e00\u4e2a goroutine \u4e2d\u7684\u884c\u4e3a\uff0c\u6587\u6863\u4e5f\u63cf\u8ff0\u4e86\uff0c\u5728 https:\/\/golang.org\/ref\/spec#Handling_panics\uff0c\u6211\u628a\u5b83\u8d34\u8fc7\u6765<\/p>\n
    While executing a function F, an explicit call to panic or a run-time panic terminates the execution of F. Any functions deferred by F are then executed as usual. Next, any deferred functions run by F’s caller are run, and so on up to any deferred by the top-level function in the executing goroutine. At that point, the program is terminated and the error condition is reported, including the value of the argument to panic. This termination sequence is called panicking.<\/p>\n
    \u6ce8\u610f\u5230”in the executing goroutine”\u7684\u9650\u5236\uff0c\u90a3\u4e48\u5c31\u662f\u8bf4 panic \u4f1a\u89e6\u53d1\u5728\u5b83\u6240\u8fd0\u884c\u7684 goroutine \u4e2d\u8c03\u7528\u94fe\u4e0a\u7684 defer\uff0c\u7136\u540e\u6574\u4e2a\u7a0b\u5e8f\u5c31\u9000\u51fa\u4e86\u3002\u6240\u4ee5 panic \u4e0d\u4f1a\u7ba1\u5176\u4ed6 goroutine \u4e2d\u7684 defer \u3002                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : lasuar <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @hallDrawnel \u7ed9\u529b\uff0c\u8981\u7684\u5c31\u662f\u8fd9\u4e2a                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : hallDrawnel <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u8bdd\u8bf4\u90a3\u4e2a\u5c0f\u5fc3\u5fc3\u662f\u600e\u4e48\u70b9\u51fa\u6765\u7684\uff1f\uff1f\u7f51\u9875\u7aef\u53ef\u4ee5\u5417\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : lasuar <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u9f20\u6807\u79fb\u5230\u5c42\u53f7\u5de6\u8fb9\u518d\u5de6\u8fb9\u7684\u4f4d\u7f6e\u5c31\u4f1a\u663e\u793a\u4e86                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : lasuar <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @hallDrawnel \u9f20\u6807\u79fb\u5230\u5c42\u53f7\u5de6\u8fb9\u518d\u5de6\u8fb9\u7684\u4f4d\u7f6e\u5c31\u4f1a\u663e\u793a\u4e86                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
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     \u8cc7\u6df1\u5927\u4f6c : yoshiyuki <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 func main() {
     defer log.Println(111)
     go func() {
     defer func() {
     recover()
     }()
     panic(222)
     }()
    }<\/p>\n
    \u62b1\u6b49\u5bf9\u4f60\u7684\u95ee\u9898\u6709\u66f2\u89e3\uff0c\u5982 8#\u6240\u8a00\uff0cdefer \u7684\u6267\u884c\u6761\u4ef6\u662f\u6709 return\uff0c\u6240\u4ee5\u4f60\u9700\u8981 recover \u4ee5\u4fdd\u969c\u4e3b\u534f\u7a0b\u4e2d return \u7684\u6267\u884c                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
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     \u8cc7\u6df1\u5927\u4f6c : CEBBCAT <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @yoshiyuki \u94c1\u5b50\uff0c\u53ef\u4ee5\u8bd5\u7528\u4e0b\u8d34 gist \u94fe\u63a5\u7684\u529f\u80fd\uff0c\u5f88\u68d2\u55f7                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : yoshiyuki <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @CEBBCAT \u8c22\u8c22\u63a8\u8350\uff0c\u6709\u64cd\u4f5c\u6307\u5357\u4e4b\u7c7b\u7684\u4e1c\u897f\u5417\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : CEBBCAT <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @yoshiyuki \u4f60\u4e5f\u8bb8\u53ef\u4ee5\u7ad9\u5185\u641c\u7d22\u4e00\u4e0b\uff0c\u6211\u660e\u5929\u4e5f\u6709\u53ef\u80fd\u53d1\u4e2a\u6559\u7a0b                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : JamesMackerel <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 go \u8fd9\u79cd\u662f\u5bf9\u79f0\u534f\u7a0b\uff0c\u6ca1\u6709\u8001\u7238\u513f\u5b50\u7684\u6982\u5ff5\u3002                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : davidyanxw <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 defer … \/\/ \u538b\u6808
    go func() {panic(222)}() \/\/ \u5b50\u534f\u7a0b<\/p>\n
    main \u534f\u7a0b\u548c\u5b50\u534f\u7a0b\u6267\u884c\u987a\u5e8f\u672a\u77e5\uff0c\u90fd\u6709\u53ef\u80fd\u5148\u6267\u884c\u7ed3\u675f
    main \u5148\u6267\u884c\u5b8c\uff1a\u4f1a\u6267\u884c main \u534f\u7a0b\u4e2d\u7684 defer
    \u5b50\u534f\u7a0b\u5148\u6267\u884c\u5b8c\uff1apanic \u4fe1\u606f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : lasuar <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @davidyanxw \u4f60\u6d4b\u8bd5\u4e00\u4e0b                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
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     \u8cc7\u6df1\u5927\u4f6c : davidyanxw <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @lasuar 
    \u6211\u4e4b\u524d\u7684\u7406\u89e3\u6709\u95ee\u9898\u3002<\/p>\n
    \u8f93\u51fa\u7ed3\u679c\u6709\u51e0\u79cd\u53ef\u80fd\uff1a
    1. main \u534f\u7a0b\u5148\u4e8e\u5b50\u534f\u7a0b\u7ed3\u675f
    \u8f93\u51fa:111
    2. \u5b50\u534f\u7a0b\u5148 panic\uff0cmain \u534f\u7a0b\u672a\u6267\u884c\u5230 println(111)
    \u8f93\u51fa\uff1apanic 222 \u3002\u3002\u3002
    3. \u5b50\u534f\u7a0b\u5148 panic\uff0cmain \u534f\u7a0b\u6267\u884c\u5230 println(111)
    \u8f93\u51fa\uff1a
    111
    panic 222 \u3002\u3002\u3002<\/p>\n
    2\/3 \u662f\u540c\u4e00\u4e2a\u903b\u8f91\uff0cpanic \u5ffd\u7565\u4e86\u4e0a\u5c42\u7684 defer<\/p>\n
    \u7ed3\u8bba\u662f\uff1a
    1. 8 \u8bf4\u7684\uff0cpanic \u53ea\u5904\u7406\u5f53\u524d\u534f\u7a0b\u7684 defer \u51fd\u6570
    2. panic \u5411\u4e0a\u629b\u51fa                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : CEBBCAT <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @yoshiyuki #15 https:\/\/www.v2ex.com\/t\/663565                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n","protected":false},"excerpt":{"rendered":"
    \u5173\u4e8e defer \u8cc7\u6df1\u5927\u4f6c : l…<\/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\/93613"}],"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=93613"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/93613\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=93613"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=93613"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=93613"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}