{"id":208198,"date":"2025-07-08T12:54:54","date_gmt":"2025-07-08T04:54:54","guid":{"rendered":"https:\/\/server.hk\/cnblog\/208198\/"},"modified":"2025-07-08T12:54:54","modified_gmt":"2025-07-08T04:54:54","slug":"%e8%87%b4%e5%91%bd%e9%94%99%e8%af%af%ef%bc%9a%e6%89%80%e6%9c%89-goroutine-%e9%83%bd%e5%9c%a8%e7%9d%a1%e8%a7%89-%e6%ad%bb%e9%94%81%ef%bc%81%e5%b0%86-waitgroup-%e4%b8%8e-for-select-%e5%be%aa%e7%8e%af","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/208198\/","title":{"rendered":"\u81f4\u547d\u9519\u8bef\uff1a\u6240\u6709 goroutine \u90fd\u5728\u7761\u89c9 – \u6b7b\u9501\uff01\u5c06 WaitGroup \u4e0e for-select \u5faa\u73af\u4e00\u8d77\u4f7f\u7528\u65f6"},"content":{"rendered":"

<\/b> <\/p>\n

\u5f53\u524d\u4f4d\u7f6e\uff1a ><\/span> ><\/span> ><\/span> ><\/span> \u81f4\u547d\u9519\u8bef\uff1a\u6240\u6709 goroutine \u90fd\u5728\u7761\u89c9 – \u6b7b\u9501\uff01\u5c06 WaitGroup \u4e0e for-select \u5faa\u73af\u4e00\u8d77\u4f7f\u7528\u65f6<\/span><\/p>\n

\u6765\u6e90\uff1astackoverflow<\/span>
\n2024-04-30 10:03:37<\/span>
\n<\/i>0\u6d4f\u89c8<\/span>
\n<\/i>\u6536\u85cf<\/span> <\/p>\n

\u76ee\u524d\u4e0a\u5df2\u7ecf\u6709\u5f88\u591a\u5173\u4e8eGolang<\/span>\u7684\u6587\u7ae0\u4e86\uff0c\u81ea\u5df1\u5728\u521d\u6b21\u9605\u8bfb\u8fd9\u4e9b\u6587\u7ae0\u4e2d\uff0c\u4e5f\u89c1\u8bc6\u5230\u4e86\u5f88\u591a\u5b66\u4e60\u601d\u8def\uff1b\u90a3\u4e48\u672c\u6587\u300a\u81f4\u547d\u9519\u8bef\uff1a\u6240\u6709 goroutine \u90fd\u5728\u7761\u89c9 – \u6b7b\u9501\uff01\u5c06 WaitGroup \u4e0e for-select \u5faa\u73af\u4e00\u8d77\u4f7f\u7528\u65f6\u300b<\/span>\uff0c\u4e5f\u5e0c\u671b\u80fd\u5e2e\u52a9\u5230\u5927\u5bb6\uff0c\u5982\u679c\u9605\u8bfb\u5b8c\u540e\u771f\u7684\u5bf9\u4f60\u5b66\u4e60Golang<\/span>\u6709\u5e2e\u52a9\uff0c\u6b22\u8fce\u52a8\u52a8\u624b\u6307\uff0c\u8bc4\u8bba\u7559\u8a00\u5e76\u5206\u4eab~<\/p>\n

\u95ee\u9898\u5185\u5bb9
\n <\/p>\n

go\u7248\u672c\uff1a<\/strong> go1.12.5 linux\/amd64<\/p>\n

\u6211\u8bd5\u56fe\u7406\u89e3 go \u4e2d\u7684 nil \u901a\u9053\u3002<\/p>\n

package main\n\nimport (\n    \"fmt\"\n    \"sync\"\n)\n\nfunc main() {\n    ch := make(chan int)\n    ch2 := make(chan int)\n    wg := sync.waitgroup{}\n    wg.add(1)\n    go func(c1 chan int, c2 chan int, w *sync.waitgroup) {\n        for c1 != nil || c2 != nil {\n            fmt.println(\"in for\")\n            fmt.println(c1, c2)\n            select {\n            case v, ok := <-c1:\n                if !ok {\n                    c1 = nil\n                    fmt.println(\"c1 closed\")\n                } else {\n                    fmt.println(v, \" recieved c1\")\n                }\n            case v, ok := <-c2:\n                if !ok {\n                    c2 = nil\n                } else {\n                    fmt.println(v, \" recieved c2\")\n                }\n            }\n        }\n        fmt.println(\"called wg.done\")\n        wg.done()\n    }(ch, ch2, &wg)\n    for i := 0; i < 4; i++ {\n        if i%2 == 0 {\n            ch <- i\n        } else {\n            ch2 <- i\n        }\n    }\n    close(ch)\n    wg.wait()\n}<\/pre>\n
\u5e76\u5728\u6807\u51c6\u8f93\u51fa\u4e0a\u6536\u5230\u6b64\u8f93\u51fa\uff1a<\/p>\n
in for\n0xc000084060 0xc0000840c0\n0  recieved c1\nin for\n0xc000084060 0xc0000840c0\n1  recieved c2\nin for\n0xc000084060 0xc0000840c0\n2  recieved c1\nin for\n0xc000084060 0xc0000840c0\n3  recieved c2\nin for\n0xc000084060 0xc0000840c0\nc1 closed\nin for\n<nil> 0xc0000840c0\nfatal error: all goroutines are asleep - deadlock!\n\ngoroutine 1 [semacquire]:\nsync.runtime_Semacquire(0xc00009a018)\n        \/usr\/local\/go\/src\/runtime\/sema.go:56 +0x39\nsync.(*WaitGroup).Wait(0xc00009a010)\n        \/usr\/local\/go\/src\/sync\/waitgroup.go:130 +0x65\nmain.main()\n        \/home\/ayush\/projects\/gojects\/src\/go-practice\/nil-channels\/main.go:44 +0x155\n\ngoroutine 18 [select]:\nmain.main.func1(0xc00009a010, 0xc000084060, 0xc0000840c0, 0xc00009a010)\n        \/home\/ayush\/projects\/gojects\/src\/go-practice\/nil-channels\/main.go:17 +0x1e5\ncreated by main.main\n        \/home\/ayush\/projects\/gojects\/src\/go-practice\/nil-channels\/main.go:13 +0xce\nexit status 2<\/pre>\n
\u4f46\u662f\u6839\u636e\u4ee3\u7801\u548c\u65e5\u5fd7\uff0cwg.done()<\/code> \u4ece\u672a\u88ab\u8c03\u7528\uff0c\u8fd9\u610f\u5473\u7740 goroutine \u4ecd\u7136\u5b58\u5728\u3002<\/p>\n
\u8c01\u80fd\u5e2e\u6211\u7406\u89e3\u8fd9\u91cc\u53d1\u751f\u4e86\u4ec0\u4e48\uff1f<\/p>\n
 <\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
 <\/p>\n
\u60a8\u4ec5\u5173\u95ed ch<\/code>\uff0c\u800c\u4e0d\u5173\u95ed ch2<\/code>\u3002\u5f53ch<\/code>\u5173\u95ed\u65f6\uff0cgoroutine\u5c06c1<\/code>\u8bbe\u7f6e\u4e3anil\uff0c\u4f46\u662fc2<\/code>\u4ecd\u7136\u4e0d\u662fnil\uff0c\u6240\u4ee5select<\/code>\u7b49\u5f85\u4ecec2<\/code>\u63a5\u6536\uff0c\u4e3bgoroutine\u5728wg.done()zqbendcz\u5904\u7b49\u5f85qb\uff0c\u6240\u4ee5\u4e24\u4e2a goroutine \u90fd\u5728\u7761\u89c9\u3002<\/p> <p>\u53d1\u751f\u8fd9\u79cd\u60c5\u51b5\u662f\u56e0\u4e3a\u60a8\u6ca1\u6709\u5173\u95ed ch2<\/code>\u3002 select \u5757\u4ecd\u5728\u7b49\u5f85 ch2<\/code>\u3002<\/code><\/p>\n
\u5de5\u4f5c\u4ee3\u7801\uff1a<\/p>\n
package main\n\nimport (\n    \"fmt\"\n    \"sync\"\n)\n\nfunc main() {\n    ch := make(chan int)\n    ch2 := make(chan int)\n    wg := sync.WaitGroup{}\n    wg.Add(1)\n\n    go func(c1 chan int, c2 chan int, w *sync.WaitGroup) {\n        for c1 != nil || c2 != nil {\n\n            select {\n            case v, ok := <-c1:\n                if !ok {\n                    c1 = nil\n                    fmt.Println(\"c1 closed\")\n                } else {\n                    fmt.Println(v, \" recieved c1\")\n                }\n            case v, ok := <-c2:\n                if !ok {\n                    c2 = nil\n                } else {\n                    fmt.Println(v, \" recieved c2\")\n                }\n            }\n        }\n\n        fmt.Println(\"called wg.Done\")\n        wg.Done()\n    }(ch, ch2, &wg)\n\n    for i := 0; i < 4; i++ {\n        if i%2 == 0 {\n            ch <- i\n            fmt.Println(\"sending to c1 \", i)\n        } else {\n            ch2 <- i\n            fmt.Println(\"sending to c2 \", i)\n        }\n    }\n    close(ch)\n    close(ch2)\n    wg.Wait()\n}<\/pre>\n
\u4eca\u5929\u5e26\u5927\u5bb6\u4e86\u89e3\u4e86\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u5e0c\u671b\u5bf9\u4f60\u6709\u6240\u5e2e\u52a9\uff1b\u5173\u4e8eGolang\u7684\u6280\u672f\u77e5\u8bc6\u6211\u4eec\u4f1a\u4e00\u70b9\u70b9\u6df1\u5165\u4ecb\u7ecd\uff0c\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u516c\u4f17\u53f7\uff0c\u4e00\u8d77\u5b66\u4e60\u7f16\u7a0b~<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f53\u524d\u4f4d\u7f6e\uff1a > > ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-208198","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208198","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=208198"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208198\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=208198"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=208198"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=208198"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}