go\u7684\u5185\u5b58\u6a21\u578b\u65e8\u5728\u8bf4\u660e\uff1a\u4e00\u4e2a\u534f\u7a0b\u4e2d\u5bf9\u53d8\u91cfv\u7684\u5199\u5165\u4ea7\u751f\u7684\u503c\u53ef\u4ee5\u4fdd\u8bc1\u88ab\u53e6\u4e00\u4e2a\u534f\u7a0b\u4e2d\u7684\u5bf9\u53d8\u91cfv\u7684\u8bfb\u53d6\u89c2\u5bdf\u5230\u3002<\/p>\n
\u5728\u4e00\u4e2a\u534f\u7a0b\u5185\uff0c\u8bfb\u5199\u64cd\u4f5c\u5fc5\u987b\u6309\u7167\u7a0b\u5e8f\u6307\u5b9a\u7684\u987a\u5e8f\u8fdb\u884c\u3002\u5728\u4e00\u4e2a\u534f\u7a0b\u5185\uff0c\u7f16\u8bd1\u5668\u548c\u5904\u7406\u5668\u53ef\u80fd\u5bf9\u8bfb\u5199\u64cd\u4f5c\u91cd\u5199\u6392\u5e8f\uff0c\u4f46\u662f\u8fd9\u4e2a\u6392\u5e8f\u7684\u524d\u63d0\u662f\uff1a\u5728 \u6211\u4eec\u8fd9\u91cc\u5b9a\u4e49 \u5728\u4e00\u4e2a\u534f\u7a0b\u5185\uff0c \u5982\u679c\u4e0b\u9762\u4e24\u70b9\u53ef\u4ee5\u4fdd\u8bc1\uff0c\u5c31\u8bf4\u660e\u5bf9\u53d8\u91cfv\u7684\u8bfb\u53d6r \u4e3a\u4e86\u4fdd\u8bc1\u53d8\u91cfv\u7684\u8bfb\u53d6r\u89c2\u5bdf\u5230v\u7684\u7279\u5b9a\u5199\u5165w\uff0c\u5e76\u4e14\u4fdd\u8bc1w\u662f\u552f\u4e00\u5141\u8bb8\u88abr\u89c2\u5bdf\u5230\u7684\u3002\u4e5f\u5c31\u662f\u8bf4\uff0cr\u4fdd\u8bc1\u80fd\u89c2\u5bdf\u5230w\u3002\u9700\u8981\u505a\u5230\u4e0b\u9762\u4e24\u70b9\uff1a<\/p>\n \u4e0b\u9762\u4e24\u70b9\u6bd4\u4e0a\u9762\u4e24\u70b9\u8981\u6c42\u66f4\u4e3a\u4e25\u683c\u3002\u5b83\u4fdd\u8bc1\u4e86\u6ca1\u6709\u5176\u4ed6\u7684\u5199\u5165w’\u548cw\u3001r\u540c\u65f6\u53d1\u751f\u3002<\/p>\n \u5728\u4e00\u4e2a\u534f\u7a0b\u5185\uff0c\u56e0\u4e3a\u6ca1\u6709\u5e76\u53d1\uff0c\u6240\u4ee5\u8fd9\u4e24\u79cd\u5b9a\u4e49\u662f\u4e00\u81f4\u7684\uff1a\u8bfb\u53d6r\u53ef\u4ee5\u89c2\u5bdf\u5230\u5199\u5165w\u5bf9\u53d8\u91cfv\u6700\u8fd1\u4e00\u6b21\u7684\u5199\u5165\u3002\u4f46\u662f\u5f53\u591a\u4e2a\u534f\u7a0b\u540c\u65f6\u8bbf\u95ee\u540c\u4e00\u4e2a\u5171\u4eab\u53d8\u91cf\u65f6\uff0c\u5c31\u5fc5\u987b\u4f7f\u7528\u540c\u6b65\u4e8b\u4ef6\u6765\u5efa\u7acb \u5728\u5185\u5b58\u6a21\u578b\u4e2d\uff0c\u5bf9\u53d8\u91cfv\u4ee50\u503c\u521d\u59cb\u5316\u662f\u4e00\u6b21\u5199\u5165\u3002<\/p>\n \u5bf9\u4e8e\u5927\u4e8e\u5355\u673a\u5668\u5b57\u8282\u7684\u8bfb\u53d6\u548c\u5199\u5165\uff0c\u53ef\u4ee5\u770b\u505a\u662f\u5bf9\u591a\u4e2a\u5355\u673a\u5668\u5b57\u8282\u7684\u4e71\u5e8f\u64cd\u4f5c\u3002<\/p>\n \u7a0b\u5e8f\u521d\u59cb\u5316\u662f\u5728\u5355\u534f\u7a0b\u5185\u8fd0\u884c\u7684\uff0c\u4f46\u662f\u8fd9\u4e2a\u534f\u7a0b\u53ef\u80fd\u521b\u5efa\u5176\u4ed6\u7684\u534f\u7a0b\u3002\u5b83\u4eec\u662f\u5e76\u53d1\u7684\u3002<\/p>\n \u5982\u679c\u5305p\u5f15\u5165\u4e86\u5305q\uff0c\u5219q\u7684\u521d\u59cb\u5316\u51fd\u6570\u4f1a\u5728p\u7684\u521d\u59cb\u5316\u51fd\u6570\u4e4b\u524d\u8fd0\u884c\u3002<\/p>\n main.main\u51fd\u6570\u5728\u6240\u6709\u7684\u521d\u59cb\u5316\u51fd\u6570\u4e4b\u540e\u8fd0\u884c\u3002<\/p>\n \u534f\u7a0b\u7684\u9500\u6bc1\u4e0d\u4fdd\u8bc1\u5728\u7a0b\u5e8f\u4e2d\u7684\u4efb\u4f55\u4e8b\u4ef6\u53d1\u751f\u4e4b\u524d\u3002\u6bd4\u5982\uff1a<\/p>\n \u8fd9\u4e2a\u8d4b\u503c\u6ca1\u6709\u8ddf\u968f\u4efb\u4f55\u540c\u6b65\u4e8b\u4ef6\uff0c\u6240\u4ee5\u5b83\u4e0d\u4fdd\u8bc1\u88ab\u5176\u4ed6\u534f\u7a0b\u89c2\u5bdf\u5230\u3002\u4e8b\u5b9e\u4e0a\uff0c\u6fc0\u8fdb\u7684\u7f16\u8bd1\u5668\u4f1a\u5220\u9664\u6574\u4e2ago\u8bed\u53e5\u3002<\/p>\n \u5982\u679c\u9700\u8981\uff0c\u53ef\u4ee5\u4f7f\u7528\u540c\u6b65\u539f\u8bed\u6bd4\u5982 \u5728go\u7684\u534f\u7a0b\u4e2d\uff0c\u7ba1\u9053\u901a\u4fe1\u662f\u975e\u5e38\u91cd\u8981\u7684\u4e00\u4e2a\u540c\u6b65\u65b9\u6cd5\u3002\u901a\u5e38\u53d1\u9001\u65b9\u548c\u63a5\u53d7\u65b9\u5728\u4e24\u4e2a\u4e0d\u540c\u7684\u534f\u7a0b\u4e2d\uff0c\u5229\u7528\u53d1\u9001\u548c\u63a5\u6536\u8fd9\u4e24\u4e2a\u6709\u5e8f\u7684\u52a8\u4f5c\u6765\u8fdb\u884c\u540c\u6b65\u3002<\/p>\n \n 1.\u5728\u6709\u7f13\u51b2\u7684\u7ba1\u9053\u4e2d\uff0c\u53d1\u9001\u4e00\u5b9a\u53d1\u751f\u5728\u63a5\u6536\u5b8c\u6210\u524d\u3002(A send on a channel happens before the corresponding receive from that channel completes.\n<\/p><\/blockquote>\n \u4f8b\u5982\uff1a<\/p>\n \n 2.\u7ba1\u9053\u7684\u5173\u95ed\u4e00\u5b9a\u53d1\u751f\u5728\u4ece\u7ba1\u9053\u4e2d\u63a5\u6536\u503c\u4e4b\u524d\u3002\n<\/p><\/blockquote>\n \u56e0\u6b64\u4e0a\u9762\u7684\u4f8b\u5b50\u5c06 \n 3.\u5728\u65e0\u7f13\u51b2\u7ba1\u9053\u4e2d\uff0c\u63a5\u6536\u4e00\u5b9a\u53d1\u751f\u5728\u53d1\u9001\u5b8c\u6210\u524d\u3002(The closing of a channel happens before a receive that returns a zero value because the channel is closed.)\n<\/p><\/blockquote>\n \u4f8b\u5982\u4e0b\u9762\u7684\u4f8b\u5b50\u5c06\u53d1\u9001\u548c\u63a5\u6536\u8bed\u53e5\u4e92\u6362\u4e86\u4f4d\u7f6e\u3002<\/p>\n \u5982\u679c\u4e0a\u8ff0\u4f8b\u5b50\u4e2d\u7ba1\u9053\u662f\u6709\u7f13\u51b2\u7684(e.g., c = make(chan int, 1)) \uff0c\u5c31\u65e0\u6cd5\u4fdd\u8bc1\u4e00\u5b9a\u80fd\u6253\u5370\u51fa \n 4.\u5728\u5bb9\u91cf\u4e3aC\u7684\u7ba1\u9053\u4e2d\uff0c\u7b2ck\u4e2a\u63a5\u6536\u53d1\u751f\u5728k+C\u4e2a\u53d1\u9001\u5b8c\u6210\u4e4b\u524d\u3002(The kth receive on a channel with capacity C happens before the k+Cth send from that channel completes.)\n<\/p><\/blockquote>\n \u7b2c4\u70b9\u63a8\u5e7f\u4e86\u7b2c\u4e00\u70b9\u7684\u89c4\u5219\u3002\u8fd9\u91cc\u5176\u5b9e\u6709\u4e00\u70b9\u7ed5\uff0c\u4e3e\u4e2a\u4f8b\u5b50\uff1a \u7b2c\u56db\u70b9\u89c4\u5219\u4f7f\u5f97 \u4e0b\u9762\u7684\u4f8b\u5b50\u9650\u5236\u4e86\u6700\u5927\u5e76\u53d1\u91cf\u4e3a3\uff1a<\/p>\n \u540c\u6837\u7684\uff0c\u6211\u4eec\u4e5f\u53ef\u4ee5\u7528lock\u548conce\u6765\u5b9e\u73b0 \u5373\u4f7f\u8bfbr\u53ef\u4ee5\u89c2\u5bdf\u5230\u540c\u65f6\u53d1\u751f\u7684\u5199w\u7684\u503c\uff0c\u4f46\u8fd9\u5e76\u4e0d\u610f\u5473\u8fd9\u5728r\u4e4b\u540e\u53d1\u751f\u7684\u8bfbr’\u53ef\u4ee5\u89c2\u5bdf\u5230\u5728w\u4e4b\u524d\u53d1\u751f\u7684\u5199w’\u3002\u4f8b\u5982\uff1a<\/p>\n \u8fd9\u6bb5\u7a0b\u5e8f\u53ef\u80fd\u6253\u5370\u51fa2\u30010<\/p>\n \u8fd9\u79cd\u73b0\u8c61\u4f7f\u5f97\u4e00\u4e9b\u5e38\u89c1\u7684\u65b9\u5f0f\u5931\u6548\u3002\u6bd4\u5982 \u8fd9\u6bb5\u7a0b\u5e8f\u4e0d\u80fd\u4fdd\u8bc1 \u540c\u6837\u7684\uff0c\u8fd8\u6709\u4e00\u79cd\u5faa\u73af\u7b49\u5f85\u7684\u5199\u6cd5\u4e5f\u53ef\u80fd\u6709\u95ee\u9898\uff0c\u4f8b\u5982\uff1a<\/p>\n \u8fd9\u6bb5\u7a0b\u5e8f\u4e5f\u4e0d\u4fdd\u8bc1 \u8fd8\u6709\u4e00\u79cd\u884d\u751f\u7248\u672c\u7684\u5199\u6cd5\u4e5f\u4f1a\u6709\u95ee\u9898<\/p>\n \u5373\u4f7f The Go Memory Model\uff08\u539f\u6587\uff09<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\u5f53\u524d\u534f\u7a0b<\/code>\u5185\uff0c\u4e0d\u4f1a\u6539\u53d8\u7a0b\u5e8f\u7684\u6267\u884c\u884c\u4e3a\u3002\u4f46\u662f\u8fd9\u4e2a\u91cd\u65b0\u6392\u5e8f\u662f\u4e0d\u4fdd\u8bc1\u5176\u4ed6\u534f\u7a0b\u89c2\u6d4b\u5230\u6267\u884c\u987a\u5e8f\u662f\u4e0d\u6539\u53d8\u7684\u3002\u6bd4\u5982\u5728\u534f\u7a0b1\u4e2da=1;b=2<\/code>\uff0c\u4f46\u5728\u5176\u4ed6\u534f\u7a0b\u7684\u611f\u77e5\u4e2d\uff0c\u53ef\u80fdb\u6bd4a\u5148\u66f4\u65b0\u503c\u3002<\/p>\nHappens Before(\u5728...\u4e4b\u524d\u53d1\u751f)<\/code>\uff0c\u5982\u679c\u4e8b\u4ef6e1\u5728\u4e8b\u4ef6e2\u4e4b\u524d\u53d1\u751f<\/code>\uff0c\u90a3\u4e48\u6211\u4eec\u5c31\u53ef\u4ee5\u8bf4e2\u5728e1\u4e4b\u540e\u53d1\u751f\u3002\u5982\u679ce1\u65e2\u4e0d\u5728e2\u4e4b\u524d\u53d1\u751f\uff0c\u4e5f\u4e0d\u5728e2\u4e4b\u540e\u53d1\u751f\u3002\u90a3\u4e48e1\u548ce2\u5c31\u662f\u540c\u65f6\u53d1\u751f\u7684\uff08\u5e76\u53d1\uff09\u3002<\/p>\nHappens Before<\/code>\u7684\u987a\u5e8f\u5c31\u662f\u7a0b\u5e8f\u8868\u8fbe\u7684\u90a3\u6837\u3002<\/p>\n\u5141\u8bb8<\/code>\u89c2\u5bdf\u5230\u5bf9\u53d8\u91cfv\u7684\u5199\u5165w\uff1a<\/p>\n\n
\n
Happens Before<\/code>\u8bed\u4e49\u6765\u4fdd\u8bc1\u8bfb\u53d6r\u53ef\u4ee5\u89c2\u5bdf\u5230\u6307\u5b9a\u7684\u5199\u5165w\u3002<\/p>\n\u540c\u6b65<\/h2>\n
\u521d\u59cb\u5316<\/h3>\n
\u534f\u7a0b\u521b\u5efa<\/h3>\n
go<\/code>\u5173\u952e\u5b57\u521b\u5efa\u534f\u7a0b\u53d1\u751f\u5728\u534f\u7a0b\u8fd0\u884c\u4e4b\u524d\u3002<\/p>\n\u534f\u7a0b\u9500\u6bc1<\/h3>\n
var a string\n\nfunc hello() {\n go func() { a = \"hello\" }()\n print(a)\n}\n<\/code><\/pre>\n\u9501<\/code>\u6216\u7ba1\u9053\u901a\u4fe1<\/code>\u6765\u5efa\u7acb\u4e00\u4e2a\u76f8\u5173\u7684\u6267\u884c\u987a\u5e8f\u3002<\/p>\n\u7ba1\u9053\u901a\u4fe1<\/h3>\n
var c = make(chan int, 10)\nvar a string\n\nfunc f() {\n a = \"hello, world\"\n c <- 0\n}\n\nfunc main() {\n go f()\n <-c\n print(a)\n}\n<\/code><\/pre>\na = \"hello, world\"<\/code>\u4e00\u5b9a\u5728c<-0<\/code>\u4e4b\u524d\u53d1\u751f\uff0cc<-0<\/code>\u4e00\u5b9a\u5728<-c<\/code>\u4e4b\u524d\u53d1\u751f\uff0c<-c<\/code>\u4e00\u5b9a\u5728print(a)<\/code>\u4e4b\u524d\u53d1\u751f\u3002\u8fd9\u6837\u5c31\u80fd\u4fdd\u8bc1a = \"hello, world\"<\/code>\u5728print(a)<\/code>\u4e4b\u524d\u53d1\u751f\u3002\u5219\u4fdd\u8bc1\u53ef\u4ee5\u6253\u5370\u51fahello, world<\/code>\u3002<\/p>\n<-c<\/code>\u66ff\u6362\u6210close(c)<\/code>\u4e5f\u662f\u53ef\u4ee5\u7684\u3002<\/p>\nvar c = make(chan int)\nvar a string\n\nfunc f() {\n a = \"hello, world\"\n <-c\n}\nfunc main() {\n go f()\n c <- 0\n print(a)\n}\n<\/code><\/pre>\nhello,world<\/code><\/p>\n\u7b2c1\u4e2a\u63a5\u6536\u53d1\u751f\u57281+C\u4e2a\u53d1\u9001\u5b8c\u6210\u4e4b\u524d<\/code>\u3002\u9996\u5148\u601d\u8003\uff1a\u7b2c\u4e00\u4e2a\u63a5\u6536\u80fd\u5426\u4fdd\u8bc1\u57280+C\u4e2a\u53d1\u9001\u5b8c\u6210\u4e4b\u524d\uff1f\u7b54\u6848\u662f\u4e0d\u80fd\u3002\u56e0\u4e3a\u7ba1\u9053\u6709C\u4e2a\u5bb9\u91cf\u7684\u7f13\u51b2\uff0cC\u4e2a\u53d1\u9001\u8bed\u53e5\u53d1\u9001\u5b8c\u6210\u524d\uff0c\u5b8c\u5168\u53ef\u4ee5\u4e0d\u8c03\u7528\u63a5\u6536\u8bed\u53e5\u3002\u90a3\u7b2c1\u4e2a\u63a5\u6536\u53d1\u751f\u57281+C\u4e2a\u53d1\u9001\u5b8c\u6210\u4e4b\u524d<\/code>\u5982\u4f55\u4fdd\u8bc1\uff0c\u6211\u4eec\u77e5\u9053\uff0c\u5f53\u7ba1\u9053\u7f13\u51b2\u6ee1\u4e86\u4e4b\u540e\uff0c\u5c31\u65e0\u6cd5\u5411\u7ba1\u9053\u4e2d\u53d1\u9001\uff0c\u53d1\u9001\u8bed\u53e5\u4f1a\u963b\u585e\u3002\u56e0\u6b64\u5fc5\u987b\u5728\u63a5\u6536\u4e4b\u540e\u53d1\u9001\u8bed\u53e5\u624d\u80fd\u7ee7\u7eed\u6267\u884c\u3002<\/p>\n\u8ba1\u6570\u4fe1\u53f7\u91cf\u53ef\u4ee5\u7531\u7f13\u51b2\u7ba1\u9053\u5efa\u6a21<\/code>\uff1a\u7ba1\u9053\u4e2d\u7684\u6570\u91cf\u5bf9\u5e94\u4e86\u5f53\u524d\u5e76\u53d1\u91cf\uff0c\u7ba1\u9053\u7684\u5bb9\u91cf\u5bf9\u5e94\u4e86\u6700\u5927\u5e76\u53d1\u91cf\u3002\u53d1\u9001\u8bed\u53e5\u5360\u7528\u4e00\u4e2a\u4fe1\u7528\u91cf\uff0c\u63a5\u6536\u8bed\u53e5\u91ca\u653e\u4e00\u4e2a\u4fe1\u53f7\u91cf\u3002\u8fd9\u662f\u9650\u5236\u5e76\u53d1\u91cf\u7684\u4e00\u4e2a\u60ef\u7528\u624b\u6bb5\u3002<\/p>\nvar limit = make(chan int, 3)\n\nfunc main() {\n for _, w := range work {\n go func(w func()) {\n limit <- 1\n w()\n <-limit\n }(w)\n }\n select{}\n}\n<\/code><\/pre>\nhappens before<\/code>\u8bed\u4e49<\/p>\n\u4e0d\u6b63\u786e\u7684\u540c\u6b65\u65b9\u5f0f<\/h2>\n
var a, b int\n\nfunc f() {\n a = 1\n b = 2\n}\n\nfunc g() {\n print(b)\n print(a)\n}\n\nfunc main() {\n go f()\n g()\n}\n<\/code><\/pre>\n\u53cc\u91cd\u9501\u5b9a\u68c0\u67e5<\/code><\/p>\nvar a string\nvar done bool\n\nfunc setup() {\n a = \"hello, world\"\n done = true\n}\n\nfunc doprint() {\n if !done {\n once.Do(setup)\n }\n print(a)\n}\n\nfunc twoprint() {\n go doprint()\n go doprint()\n}\n<\/code><\/pre>\nprint(a)<\/code>\u65f6\u80fd\u591f\u89c2\u5bdf\u5230a\u7684\u503c\u4e00\u5b9a\u662fhello, world<\/code>\u3002<\/p>\nvar a string\nvar done bool\n\nfunc setup() {\n a = \"hello, world\"\n done = true\n}\n\nfunc main() {\n go setup()\n for !done {\n }\n print(a)\n}\n<\/code><\/pre>\nprint(a)<\/code>\u4e00\u5b9a\u80fd\u6253\u5370\u51fa\u5185\u5bb9\uff0c\u751a\u81f3\u66f4\u574f\u7684\u60c5\u51b5\u4e0b\u65e0\u6cd5\u89c2\u5bdf\u5230done<\/code>\u53d1\u751f
\n\u4e86\u6539\u53d8\uff0c\u56e0\u6b64\u7a0b\u5e8f\u4f1a\u6b7b\u5faa\u73af\u4e0b\u53bb\u3002<\/p>\ntype T struct {\n msg string\n}\n\nvar g *T\n\nfunc setup() {\n t := new(T)\n t.msg = \"hello, world\"\n g = t\n}\n\nfunc main() {\n go setup()\n for g == nil {\n }\n print(g.msg)\n}\n<\/code><\/pre>\nmain<\/code>\u534f\u7a0b\u89c2\u5bdf\u5230\u4e86g\u88ab\u8d4b\u503c\uff0c\u4e5f\u4e0d\u4e00\u5b9a\u80fd\u89c2\u5bdf\u5230g.msg<\/code>\u6709\u503c\u3002<\/p>\n\u53c2\u8003<\/h2>\n