{"id":116269,"date":"2026-10-21T02:24:55","date_gmt":"2026-10-20T18:24:55","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/116269.html"},"modified":"2026-10-21T02:24:55","modified_gmt":"2026-10-20T18:24:55","slug":"posix%e4%bf%a1%e5%8f%b7%e9%87%8f%e4%b8%8e%e7%8e%af%e5%bd%a2%e9%98%9f%e5%88%97","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/116269.html","title":{"rendered":"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217"},"content":{"rendered":"

\u4e00\u3001\u5148\u56de\u987e：\u4fe1\u53f7\u91cf\u5230\u5e95\u662f\u4e2a\u4ec0\u4e48\u4e1c\u897f<\/h3>\n

1.1 \u4fe1\u53f7 \u2260 \u4fe1\u53f7\u91cf<\/h4>\n

\u4fe1\u53f7\u548c\u4fe1\u53f7\u91cf，\u662f\u300c\u8001\u5a46\u300d\u548c\u300c\u8001\u5a46\u997c\u300d\u7684\u5173\u7cfb \u2014\u2014 \u6ca1\u6709\u4efb\u4f55\u5173\u7cfb\u3002<\/p>\n\n\u4fe1\u53f7（signal）\u4fe1\u53f7\u91cf（semaphore \/ \u4fe1\u53f7\u706f）<\/tr>\n\n\n\n\n
\u672c\u8d28<\/td>\n\u4e00\u79cd\u8fdb\u7a0b\u95f4\u5f02\u6b65\u901a\u77e5\u7684\u65b9\u5f0f<\/td>\n\u4e00\u4e2a\u8ba1\u6570\u5668<\/td>\n<\/tr>\n
\u4f5c\u7528<\/td>\n\u901a\u77e5\u4f60"\u51fa\u4e8b\u4e86"<\/td>\n\u8868\u660e\u4e34\u754c\u8d44\u6e90\u4e2d\u8d44\u6e90\u6570\u91cf\u8fd8\u5269\u591a\u5c11<\/td>\n<\/tr>\n
\u6bd4\u55bb<\/td>\n\u95e8\u94c3<\/td>\n\u505c\u8f66\u573a\u7684\u4f59\u4f4d\u663e\u793a\u5c4f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

1.2 POSIX \u4e0e System V<\/h4>\n
    \n
  • sem_init \/ sem_wait \/ sem_post \u8fd9\u4e00\u5957\u5c5e\u4e8e POSIX \u6807\u51c6（\u53ef\u79fb\u690d\u64cd\u4f5c\u7cfb\u7edf\u63a5\u53e3）<\/li>\n
  • \u4e4b\u524d\u8fdb\u7a0b\u95f4\u901a\u4fe1\u5b66\u7684 semget \/ semop \/ semctl \u5c5e\u4e8e System V \u6807\u51c6<\/li>\n
  • POSIX \u7cfb\u5217\u662f\u6700\u5e38\u7528\u7684，System V \u57fa\u672c\u5df2\u7ecf\u7b97\u88ab\u6dd8\u6c70\u4e86<\/li>\n
  • \u77e5\u9053\u5b83\u4fe9\u662f\u4e24\u5957\u6807\u51c6\u5c31\u53ef\u4ee5，\u7406\u8bba\u5b8c\u5168\u4e00\u6837，\u6ca1\u6709\u533a\u522b<\/li>\n<\/ul>\n

    \u2714 \u5173\u952e\u70b9：\u4ee5\u524d\u8bb2 System V \u4fe1\u53f7\u91cf\u65f6\u662f\u5728"\u8fdb\u7a0b\u95f4\u901a\u4fe1"\u91cc\u8bb2\u7684，\u4eca\u5929\u5728"\u7ebf\u7a0b"\u91cc\u8bb2 POSIX \u4fe1\u53f7\u91cf \u2014\u2014 \u7406\u8bba\u4e00\u6a21\u4e00\u6837，\u53ea\u662f\u4f5c\u7528\u7684\u8303\u56f4\u4ece\u8fdb\u7a0b\u53d8\u6210\u4e86\u7ebf\u7a0b（sem_init \u7684 pshared \u53c2\u6570\u63a7\u5236）\u3002<\/p>\n

    \n

    \u4e8c\u3001\u2605 \u672c\u8d28\u7ed3\u8bba\u4e00：\u8ba1\u6570\u5668 = \u5bf9\u7279\u5b9a\u8d44\u6e90\u7684\u300c\u9884\u8ba2\u673a\u5236\u300d<\/h3>\n

    2.1 \u7535\u5f71\u9662：\u4e70\u7968\u90a3\u4e00\u523b，\u5ea7\u4f4d\u5c31\u662f\u4f60\u7684\u4e86<\/h4>\n

    \u7528\u7535\u5f71\u9662\u4e3e\u4f8b：<\/p>\n

    \u4f60\u662f\u5c41\u80a1\u5750\u5728\u5ea7\u4f4d\u4e0a，\u8fd9\u4e2a\u5ea7\u4f4d\u8d44\u6e90\u624d\u5c5e\u4e8e\u4f60？\u8fd8\u662f\u7968\u4e70\u5230\u4e86，\u5ea7\u4f4d\u5c31\u662f\u4f60\u7684\u4e86？
    \n\u7968\u4e70\u6210\u529f\u7684\u90a3\u4e00\u523b，\u5ea7\u4f4d\u5c31\u662f\u6211\u7684\u4e86\u3002\u54ea\u6015\u4eca\u5929\u8fd9\u573a\u7535\u5f71\u6211\u4e0d\u53bb\u770b，\u90a3\u4e2a\u5ea7\u4f4d\u4e5f\u5fc5\u987b\u7ed9\u6211\u7559\u7740\u3002<\/p>\n

    \u7531\u6b64\u5f97\u51fa\u672c\u7ae0\u6700\u91cd\u8981\u7684\u4e00\u6761\u7ed3\u8bba：<\/p>\n

    \u4fe1\u53f7\u91cf\u7684\u672c\u8d28\u662f\u4e00\u4e2a\u8ba1\u6570\u5668，\u662f\u5bf9\u7279\u5b9a\u8d44\u6e90\u7684\u300c\u9884\u8ba2\u673a\u5236\u300d\u3002<\/p>\n

    \"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"<\/p>\n

    2.2 \u843d\u5230\u4ee3\u7801\u4e0a\u5c31\u662f\u4e09\u884c<\/h4>\n

    int<\/span> sem =<\/span> 50<\/span>;<\/span> \/\/ \u653e\u6620\u5385 50 \u4e2a\u5ea7\u4f4d \u2192 \u8ba1\u6570\u5668\u521d\u503c = \u8d44\u6e90\u603b\u6570<\/span><\/p>\n

    \/\/ \u4e70\u7968 = \u7533\u8bf7\u8d44\u6e90 = P \u64cd\u4f5c<\/span>
    \nsem—<\/span>;<\/span> \/\/ \u7533\u8bf7\u4e00\u4e2a<\/span>
    \nif<\/span> (<\/span>sem <<\/span> 0<\/span>)<\/span> \/\/ \u51cf\u5230\u8d1f\u6570 = \u6ca1\u7968\u4e86<\/span>
    \n \u963b\u585e\u6302\u8d77;<\/span> \/\/ \u6392\u961f\u7b49\u522b\u4eba\u9000\u7968（\u4e0d\u662f\u5fd9\u7b49！）<\/span><\/p>\n

    \/\/ \u9000\u7968 \/ \u7528\u5b8c\u5f52\u8fd8 = V \u64cd\u4f5c<\/span>
    \nsem++<\/span>;<\/span><\/p>\n

    💡 \u8fd9\u6837\u5c31\u80fd\u4fdd\u8bc1：\u8fdb\u653e\u6620\u5385\u7684\u4eba\u6570\u6c38\u8fdc\u4e0d\u4f1a\u8d85\u8fc7\u5ea7\u4f4d\u6570，\u6700\u591a\u76f8\u7b49\u3002\u518d\u901a\u8fc7\u5408\u7406\u7684\u8c03\u5ea6\u8ba9\u4e0d\u540c\u7ebf\u7a0b\u5750\u4e0d\u540c\u5ea7\u4f4d \u2014\u2014 \u5927\u5bb6\u5c31\u80fd\u540c\u65f6\u8bbf\u95ee\u653e\u6620\u5385\u91cc\u4e0d\u540c\u7684\u5ea7\u4f4d\u4e86\u3002<\/p>\n

    2.3 \u653e\u6620\u5385\u6700\u6015\u7684\u4e24\u4ef6\u4e8b<\/h4>\n\n\u4e8b\u6545\u6280\u672f\u542b\u4e49<\/tr>\n\n\n\n
    \u7968\u5356\u591a\u4e86<\/td>\n\u8ba1\u6570\u5668\u51cf\u5230\u8d1f\u6570\u8fd8\u653e\u4eba\u8fdb\u6765 \u2192 \u8d85\u5356 \u2192 \u6570\u636e\u88ab\u8986\u76d6<\/td>\n<\/tr>\n
    \u7968\u53f7\u91cd\u590d<\/td>\n\u4e24\u4e2a\u7ebf\u7a0b\u62ff\u5230\u540c\u4e00\u4e2a\u4f4d\u7f6e \u2192 \u540c\u65f6\u8bfb\u5199\u540c\u4e00\u5757\u5185\u5b58 \u2192 \u6570\u636e\u4e0d\u4e00\u81f4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    \u2714 \u8fd9\u4e24\u6761\u6b63\u597d\u5bf9\u5e94\u540e\u9762\u73af\u5f62\u961f\u5217\u7684\u4e24\u6761\u94c1\u5f8b：
    \n\u2460 \u4e0d\u8981\u8bbf\u95ee\u540c\u4e00\u4e2a\u4f4d\u7f6e（\u4e92\u65a5）；\u2461 \u4e0d\u8981\u653e\u5165\u8fc7\u591a\u7684\u8fdb\u7a0b\u8fdb\u6765（\u9650\u6d41）\u3002<\/p>\n

    2.4 \u4e3a\u4ec0\u4e48"\u4e70\u7968"\u4e0d\u7b97\u8bbf\u95ee\u8d44\u6e90？<\/h4>\n

    \u8fd9\u662f\u8fd9\u5957\u6bd4\u55bb\u6700\u5999\u7684\u5730\u65b9：<\/p>\n

      \n
    • \u4e70\u7968 = \u9884\u8ba2\u6210\u529f，\u7968\u8fd8\u6ca1\u7528 \u2192 \u53ea\u662f\u628a"\u8fd8\u5269\u591a\u5c11\u4efd"\u8fd9\u4e2a\u5224\u5b9a\u7ed9\u505a\u6389\u4e86<\/li>\n
    • \u771f\u6b63\u8fdb\u573a\u843d\u5ea7 = \u8bbf\u95ee\u4e34\u754c\u8d44\u6e90<\/li>\n<\/ul>\n

      💡 \u6240\u4ee5\u4fe1\u53f7\u91cf\u628a\u300c\u8d44\u6e90\u591f\u4e0d\u591f\u300d\u7684\u5224\u5b9a，\u63d0\u524d\u5230\u4e86\u8bbf\u95ee\u4e34\u754c\u8d44\u6e90\u4e4b\u524d，\u5e76\u4e14\u662f\u539f\u5b50\u5b8c\u6210\u7684\u3002\u8fd9\u4e00\u70b9\u5728\u7b2c\u5341\u8282\u4f1a\u518d\u62d4\u9ad8\u4e00\u6b21\u3002<\/p>\n

      \n

      \u4e09\u3001\u4e8c\u5143\u4fe1\u53f7\u91cf\u5c31\u662f\u4e92\u65a5\u9501<\/h3>\n

      \u7ee7\u7eed\u5f80\u4e0b\u63a8：<\/p>\n

        \n
      • \u666e\u901a\u653e\u6620\u5385\u6709 50 \u4e2a\u5ea7\u4f4d \u2192 sem = 50 \u2192 \u591a\u5143\u4fe1\u53f7\u91cf<\/li>\n
      • \u8d85\u7ea7 VIP \u653e\u6620\u5385\u53ea\u6709 1 \u4e2a\u5ea7\u4f4d \u2192 sem = 1 \u2192 \u4e8c\u5143\u4fe1\u53f7\u91cf<\/li>\n<\/ul>\n

        sem = 1 \u65f6：\u4f60\u7533\u8bf7\u4e00\u6b21\u6210\u529f\u4e86，\u6574\u4e2a\u653e\u6620\u5385\u5c31\u662f\u4f60\u7684；\u7533\u8bf7\u5931\u8d25\u5c31\u7b49\u7740\u3002<\/p>\n

        \u4e8c\u5143\u4fe1\u53f7\u91cf\u7684\u672c\u8d28，\u4e0d\u5c31\u662f\u4e92\u65a5\u5417？<\/p>\n

        \u800c\u4e92\u65a5\u6211\u4eec\u5df2\u7ecf\u5b66\u8fc7\u4e86 \u2014\u2014 \u6240\u4ee5 mutex \u53ef\u4ee5\u770b\u4f5c\u4e8c\u5143\u4fe1\u53f7\u91cf\u7684\u4e00\u4e2a\u7279\u4f8b\u5b9e\u73b0\u3002<\/p>\n

        \u2714 \u8bb0\u6cd5：\u4fe1\u53f7\u91cf\u53ea\u6709 1 \u6216 0 \u4e24\u79cd\u72b6\u6001\u7684，\u53eb\u4e8c\u5143\u4fe1\u53f7\u91cf，\u5b83\u5c31\u662f\u4e92\u65a5\u3002<\/p>\n

        \n

        \u56db\u3001\u2605 \u672c\u8d28\u7ed3\u8bba\u4e8c：\u4e24\u79cd\u4f7f\u7528\u573a\u666f，\u51b3\u5b9a\u4f60\u7528 mutex \u8fd8\u662f sem<\/h3>\n

        \u8fd9\u662f\u672c\u7ae0\u7b2c\u4e8c\u4e2a\u91cd\u8981\u7ed3\u8bba，\u4e5f\u662f\u6574\u4e2a\u9009\u578b\u7684\u5206\u6c34\u5cad\u3002<\/p>\n

        \"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"<\/p>\n

        \u573a\u666f\u4e00：\u628a\u76ee\u6807\u8d44\u6e90\u6574\u4f53\u4f7f\u7528<\/h4>\n

        \u5178\u578b\u4f8b\u5b50\u5c31\u662f\u4e0a\u4e00\u7ae0\u6211\u4eec\u5199\u7684 \u57fa\u4e8e\u6761\u4ef6\u53d8\u91cf\u7684\u963b\u585e\u961f\u5217\u3002<\/p>\n

        \u201c\u6211\u4eec\u7684\u963b\u585e\u961f\u5217\u91cc，std::queue \u662f\u5bb9\u5668\u9002\u914d\u5668，\u5b83\u5185\u90e8\u5c01\u88c5\u7684\u7c7b\u91cc\u9762\u6709\u5934\u6307\u9488\u3001\u6709\u5c3e\u6307\u9488，\u8fd8\u8981\u505a\u7a7a\u95f4\u7684\u4e8c\u6b21\u6269\u5bb9\u3002\u4f60\u5728 pop \u7684\u65f6\u5019\u5b83\u53ef\u80fd\u6b63\u5728 push，\u6b63\u5728\u4e8c\u6b21\u6269\u5bb9 \u2014\u2014 pop \u4e0d\u5c31\u5931\u8d25\u4e86\u5417？\u6240\u4ee5\u90a3\u79cd\u961f\u5217\u5b83\u4e0d\u80fd\u591f\u5e76\u53d1\u8d77\u6765，\u53ea\u80fd\u88ab\u67d0\u4e00\u4e2a\u751f\u4ea7\u8005\u6216\u67d0\u4e00\u4e2a\u6d88\u8d39\u8005\u5355\u72ec\u4f7f\u7528\u3002\u201d<\/p>\n

        \u6240\u4ee5\u963b\u585e\u961f\u5217\u5fc5\u987b\u6574\u4f53\u52a0\u9501 \u2192 \u7528 mutex \u6216\u4e8c\u5143\u4fe1\u53f7\u91cf\u3002<\/p>\n

        \u573a\u666f\u4e8c：\u628a\u76ee\u6807\u8d44\u6e90\u6309\u5757\u5206\u6279\u4f7f\u7528<\/h4>\n

        \u201c\u6211\u4eec\u8bbf\u95ee\u5185\u5b58\u7a7a\u95f4\u8bfb\u6570\u636e\u5199\u6570\u636e，\u996d\u4e5f\u5f97\u4e00\u53e3\u4e00\u53e3\u5403，\u7a7a\u95f4\u6211\u7ed9\u4f60\u7533\u8bf7\u4e00\u5927\u5806，\u4f60\u4e5f\u662f\u4e00\u4e2a\u4e00\u4e2a\u8fc7\u7684\u3002\u201d<\/p>\n

        \u5982\u679c\u4e00\u5757\u5927\u8d44\u6e90\u53ef\u4ee5\u88ab\u5212\u5206\u6210\u4e00\u5c0f\u5757\u4e00\u5c0f\u5757，\u800c\u4e14\u6bcf\u4e2a\u7ebf\u7a0b\u8bbf\u95ee\u4e0d\u540c\u7684\u5757，\u90a3\u5c31\u5b8c\u5168\u6ca1\u6709\u51b2\u7a81 \u2014\u2014 \u53ef\u4ee5\u8ba9\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8fdb\u6765\u3002<\/p>\n

        \u8981\u505a\u7684\u4e8b\u60c5\u65e0\u975e\u4e24\u70b9：\u2460 \u4e0d\u8981\u653e\u8fc7\u591a\u7684\u8fdb\u7a0b\/\u7ebf\u7a0b\u8fdb\u6765；\u2461 \u4e0d\u8981\u8ba9\u591a\u4e2a\u7ebf\u7a0b\u8bbf\u95ee\u540c\u4e00\u4e2a\u4f4d\u7f6e\u3002<\/p>\n

        \u2192 \u8fd9\u65f6\u5019\u7528\u591a\u5143\u4fe1\u53f7\u91cf（sem = N）\u3002<\/p>\n

        \u9009\u578b\u7ed3\u8bba<\/h4>\n\n\u8d44\u6e90\u4f7f\u7528\u65b9\u5f0f\u7528\u4ec0\u4e48\u7406\u7531<\/tr>\n\n\n\n
        \u6574\u4f53\u4f7f\u7528，\u4e00\u6b21\u53ea\u8bb8\u4e00\u4e2a\u4eba\u5b8c\u6574\u5360\u7528<\/td>\nmutex \/ \u4e8c\u5143\u4fe1\u53f7\u91cf<\/td>\n\u5fc5\u987b\u4e32\u884c<\/td>\n<\/tr>\n
        \u6309\u5757\u5206\u6279\u4f7f\u7528，\u5404\u7ebf\u7a0b\u8bbf\u95ee\u4e0d\u540c\u5757<\/td>\n\u591a\u5143\u4fe1\u53f7\u91cf<\/td>\n\u53ef\u4ee5\u771f\u6b63\u5e76\u53d1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
        \n

        \u4e94\u3001\u4e3a\u4ec0\u4e48 P \/ V \u5fc5\u987b\u539f\u5b50：\u4fe1\u53f7\u91cf\u672c\u8eab\u4e5f\u662f\u4e34\u754c\u8d44\u6e90<\/h3>\n

        \u8fd9\u4e00\u6b65\u63a8\u5bfc\u7279\u522b\u5173\u952e，\u662f\u6574\u4e2a\u4fe1\u53f7\u91cf\u80fd\u6210\u7acb\u7684\u524d\u63d0\u3002<\/p>\n

        5.1 \u63a8\u5bfc\u94fe<\/h4>\n
      • \u6240\u6709\u7ebf\u7a0b\u8bbf\u95ee\u8d44\u6e90\u4e4b\u524d，\u90fd\u5f97\u5148\u770b\u4fe1\u53f7\u91cf<\/li>\n
      • \u4fe1\u53f7\u91cf\u53c8\u5fc5\u987b\u88ab\u6240\u6709\u4eba\u770b\u5230 \u2192 \u5b83\u662f\u4e2a\u5171\u4eab\u53d8\u91cf<\/li>\n
      • \u5171\u4eab\u53d8\u91cf ++ \/ — \u4e0d\u662f\u539f\u5b50\u7684（\u7ebf\u7a0b\u4e92\u65a5\u90a3\u4e00\u7ae0\u5df2\u7ecf\u7528\u4e09\u6761\u6c47\u7f16\u8bc1\u660e\u8fc7）<\/li>\n
      • \u6240\u4ee5 \u2014\u2014 \u4fe1\u53f7\u91cf\u672c\u8eab\u4e5f\u662f\u4e34\u754c\u8d44\u6e90！<\/li>\n

        \u8001\u5e08\u539f\u8bdd：\u201c\u6211\u4eec\u4fe1\u53f7\u91cf\u4e0d\u80fd\u662f\u4e00\u4e2a\u7b80\u5355\u7684 int count \u52a0\u52a0\u3001\u51cf\u51cf，\u90a3\u4e0d\u884c，\u90a3\u5e76\u4e0d\u662f\u539f\u5b50\u7684\u3002\u201d<\/p>\n

        5.2 \u4e8e\u662f\u6709\u4e86 P \u548c V<\/h4>\n\n\u64cd\u4f5c\u8bed\u4e49\u672c\u8d28<\/tr>\n\n\n\n
        P \u64cd\u4f5c<\/td>\n\u7533\u8bf7\u8d44\u6e90（sem_wait）<\/td>\n\u5bf9\u4fe1\u53f7\u91cf\u7684\u503c\u505a –，\u5fc5\u987b\u539f\u5b50<\/td>\n<\/tr>\n
        V \u64cd\u4f5c<\/td>\n\u91ca\u653e\u8d44\u6e90（sem_post）<\/td>\n\u5bf9\u4fe1\u53f7\u91cf\u7684\u503c\u505a ++，\u5fc5\u987b\u539f\u5b50<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        💡 P \/ V \u6765\u81ea\u8377\u5170\u8bed（Proberen \u5c1d\u8bd5 \/ Verhogen \u589e\u52a0），Dijkstra \u63d0\u51fa\u7684\u3002\u56fd\u5185\u6559\u6750\u901a\u7528 P\/V \u8bb0\u6cd5，\u4ee3\u7801\u91cc\u53eb sem_wait \/ sem_post\u3002<\/p>\n

        5.3 \u80fd\u4e0d\u80fd\u81ea\u5df1\u7528\u300c\u9501 + \u8ba1\u6570\u5668\u300d\u5b9e\u73b0\u4e00\u4e2a\u4fe1\u53f7\u91cf？<\/h4>\n

        \u53ef\u4ee5\u3002 \u4e00\u628a\u9501\u4fdd\u62a4\u4e00\u4e2a int count，\u5c31\u80fd\u6a21\u62df\u4fe1\u53f7\u91cf\u7684\u884c\u4e3a\u3002<\/p>\n

        \u4f46：\u4e0d\u91cd\u8981\u3002\u5173\u952e\u662f"\u60f3\u8bbf\u95ee\u8d44\u6e90\u5fc5\u987b\u5148\u8fc7\u4fe1\u53f7\u91cf\u8fd9\u4e00\u5173" \u2014\u2014
        \nP \u6210\u529f = \u9884\u8ba2\u6210\u529f = \u91cc\u9762\u4e00\u5b9a\u6709\u4e00\u4efd\u8d44\u6e90\u662f\u7ed9\u4f60\u7559\u7740\u7684\u3002<\/p>\n

        \n

        \u516d\u3001\u94fa\u57ab：\u73af\u5f62\u961f\u5217，\u4ee5\u53ca"\u7a7a\u548c\u6ee1"\u7684\u8001\u95ee\u9898<\/h3>\n

        6.1 \u590d\u4e60：\u73af\u5f62\u961f\u5217\u957f\u4ec0\u4e48\u6837<\/h4>\n
          \n
        • \u5b83\u4e5f\u662f\u4e2a\u961f\u5217，\u6240\u4ee5\u4e00\u5b9a\u6709\u5934\u6709\u5c3e（head \/ tail）<\/li>\n
        • \u521d\u59cb\u65f6 head == tail<\/li>\n
        • \u5f80\u5c3e\u90e8\u63d2\u5165\u5143\u7d20，tail \u5f80\u540e\u79fb；\u79fb\u5230\u672b\u5c3e\u5c31\u7ed5\u56de\u5f00\u5934 \u2014\u2014 \u8fd9\u5c31\u662f"\u73af"<\/li>\n<\/ul>\n

          6.2 \u81f4\u547d\u95ee\u9898：\u7a7a\u548c\u6ee1\u6307\u5411\u540c\u4e00\u4e2a\u4f4d\u7f6e<\/h4>\n

          \u7a7a：head == tail
          \n\u6ee1：head == tail \u2190 \u4e00\u6a21\u4e00\u6837，\u5206\u4e0d\u51fa\u6765<\/p>\n

          \u7ecf\u5178\u7684\u4e24\u79cd\u89e3\u51b3\u65b9\u6848：<\/p>\n\n\u65b9\u6848\u505a\u6cd5\u4ee3\u4ef7<\/tr>\n\n\n\n
          \u65b9\u6848 1<\/td>\n\u52a0\u4e00\u4e2a\u8ba1\u6570\u5668 int count：\u5165\u961f count++，\u51fa\u961f count–\u7a7a\u65f6 count == 0，\u6ee1\u65f6 count == N<\/td>\n\u591a\u4e00\u4e2a\u53d8\u91cf\u8981\u7ef4\u62a4<\/td>\n<\/tr>\n
          \u65b9\u6848 2<\/td>\n\u7a7a\u4e00\u4e2a\u4f4d\u7f6e：tail + 1 == head \u89c6\u4e3a\u6ee1，\u6c38\u8fdc\u7559\u4e00\u4e2a\u683c\u5b50\u4e0d\u7528<\/td>\n\u6d6a\u8d39\u4e00\u4e2a\u69fd\u4f4d<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

          6.3 \u7269\u7406\u5b9e\u73b0：\u56fa\u5b9a\u957f\u5ea6\u6570\u7ec4 + \u6a21\u8fd0\u7b97<\/h4>\n

          \u8bfe\u4ef6\u677f\u4e66\u7ed9\u7684\u662f\u6700\u6734\u7d20\u4e5f\u6700\u5b9e\u7528\u7684\u505a\u6cd5：<\/p>\n

          int<\/span> head =<\/span> 0<\/span>;<\/span>
          \nint<\/span> tail =<\/span> 0<\/span>;<\/span><\/p>\n

          tail++<\/span>;<\/span> tail %=<\/span> N;<\/span> \/\/ \u5165\u961f\u540e\u7ed5\u56de<\/span>
          \nhead++<\/span>;<\/span> head %=<\/span> N;<\/span> \/\/ \u51fa\u961f\u540e\u7ed5\u56de<\/span><\/p>\n

          \u4f46\u662f：\u201c\u4f60\u5f80\u540e\u79fb\u4e0d\u5c31\u8d85\u8303\u56f4\u4e86\u5417？\u968f\u65f6\u90fd\u53ef\u80fd\u5d29\u6389\u3002\u6240\u4ee5 tail++ \u4e4b\u540e\u4e0d\u7ba1\u662f\u4ec0\u4e48，\u76f4\u63a5\u6a21\u4e0a N\u3002\u201d<\/p>\n

          💡 \u903b\u8f91\u4e0a\u662f\u73af，\u7269\u7406\u4e0a\u5c31\u662f\u4e00\u4e2a\u957f\u5ea6\u4e3a N \u7684\u6570\u7ec4 + \u6a21\u8fd0\u7b97\u3002\u5f53\u7136\u4f60\u4e5f\u53ef\u4ee5\u7528\u5355\u94fe\u8868\u9996\u5c3e\u76f8\u8fde\u505a，\u6ca1\u5fc5\u8981\u3002<\/p>\n

          6.4 \u4f46\u4eca\u5929，\u6211\u4eec\u4e0d\u5224\u65ad\u7a7a\u6ee1<\/h4>\n

          \u201c\u6211\u4eca\u5929\u8981\u8bb2\u7684\u548c\u73af\u5f62\u961f\u5217\u6709\u5173，\u4f46\u6211\u4eec\u4e0d\u9700\u8981\u518d\u53bb\u5224\u65ad\u4ec0\u4e48\u4e3a\u7a7a\u4e3a\u6ee1\u4e86，\u538b\u6839\u5c31\u4e0d\u7528\u5173\u5fc3 \u2014\u2014 \u56e0\u4e3a\u6211\u4eca\u5929\u8981\u5b8c\u6210\u7684\u662f\u57fa\u4e8e\u73af\u5f62\u961f\u5217\u7684\u751f\u4ea7\u8005\u6d88\u8d39\u8005\u6a21\u578b，\u4f60\u5230\u5e95\u6709\u6ca1\u6709\u6ee1\u3001\u6709\u6ca1\u6709\u7a7a，\u6211\u4eec\u662f\u6709\u5176\u4ed6\u65b9\u6848\u6765\u8861\u91cf\u7684\u3002\u8fd9\u4e2a\u65b9\u6848\u5c31\u53eb\u505a\u4fe1\u53f7\u91cf\u3002\u201d<\/p>\n

          \n

          \u4e03\u3001\u2605 \u8ffd\u9010\u6e38\u620f：\u56db\u6761\u7ea6\u5b9a<\/h3>\n

          \u628a\u73af\u5f62\u961f\u5217\u6bd4\u55bb\u6210\u4e00\u5f20\u5927\u5706\u684c，\u6bcf\u4e2a\u683c\u5b50\u5c31\u662f\u4e00\u4e2a\u76d8\u5b50：<\/p>\n

            \n
          • \u6211\u662f\u751f\u4ea7\u8005，\u5f80\u76d8\u5b50\u91cc\u653e\u82f9\u679c<\/li>\n
          • \u4f60\u662f\u6d88\u8d39\u8005，\u4ece\u76d8\u5b50\u91cc\u62ff\u82f9\u679c<\/li>\n
          • \u6211\u4ece\u5c3e\u90e8\u5f00\u59cb\u653e，\u4f60\u4ece\u5934\u90e8\u5f00\u59cb\u62ff<\/li>\n<\/ul>\n

            7.1 \u6e38\u620f\u662f\u8fd9\u6837\u8fdb\u884c\u7684<\/h4>\n
          • \u76d8\u5b50\u5168\u7a7a\u65f6，\u4e24\u4e2a\u4eba\u6307\u5411\u540c\u4e00\u4e2a\u4f4d\u7f6e \u2192 \u4f60\u5f97\u8ba9\u6211\u5148\u751f\u4ea7（\u4f60\u62ff\u4e5f\u62ff\u4e0d\u5230，\u91cc\u9762\u538b\u6839\u6ca1\u6709）<\/li>\n
          • \u6211\u4e00\u76f4\u653e\u3001\u4e00\u76f4\u653e，\u653e\u6ee1\u4e86 \u2192 \u4e24\u4e2a\u4eba\u53c8\u6307\u5411\u540c\u4e00\u4e2a\u4f4d\u7f6e<\/li>\n
          • \u8fd9\u65f6\u5019\u6211\u4e0d\u80fd\u518d\u653e\u4e86（\u518d\u653e\u5c31\u628a\u5386\u53f2\u4e0a\u7684\u82f9\u679c\u8986\u76d6\u4e86，\u76d8\u5b50\u653e\u4e0d\u4e0b\u4f1a\u6389）<\/li>\n
          • \u6362\u4f60\u62ff，\u4f60\u62ff\u62ff\u62ff，\u62ff\u7a7a\u4e86 \u2192 \u4e24\u4e2a\u4eba\u53c8\u56de\u5230\u540c\u4e00\u4e2a\u4f4d\u7f6e<\/li>\n
          • \u53c8\u8f6e\u5230\u6211\u751f\u4ea7 \u2014\u2014 \u8fd9\u662f\u4e00\u573a\u8ffd\u9010\u6e38\u620f<\/li>\n

            \u64cd\u573a\u8dd1\u5708\u7684\u6bd4\u55bb：\u4f60\u7ad9\u7740\u4e0d\u52a8，\u6211\u4e00\u76f4\u8dd1，\u5f53\u6211\u5957\u4f60\u6574\u6574\u4e00\u5708\u65f6，\u6211\u4eec\u5c31\u5728\u540c\u4e00\u4e2a\u4f4d\u7f6e\u4e86\u3002<\/p>\n

            \"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"<\/p>\n

            7.2 \u56db\u6761\u7ea6\u5b9a（\u7f3a\u4e00\u4e0d\u53ef）<\/h4>\n\n\u7ea6\u5b9a\u5185\u5bb9\u4e3a\u4ec0\u4e48<\/tr>\n\n\n\n\n\n
            \u7ea6\u5b9a 1<\/td>\n\u4e3a\u7a7a，\u751f\u4ea7\u8005\u5148\u8fd0\u884c<\/td>\n\u7a7a\u7684\u65f6\u5019\u6d88\u8d39\u8005\u62ff\u4e0d\u5230\u4efb\u4f55\u4e1c\u897f<\/td>\n<\/tr>\n
            \u7ea6\u5b9a 2<\/td>\n\u4e3a\u6ee1，\u6d88\u8d39\u8005\u5148\u8fd0\u884c<\/td>\n\u6ee1\u7684\u65f6\u5019\u751f\u4ea7\u8005\u518d\u653e\u5c31\u4f1a\u8986\u76d6\u6570\u636e<\/td>\n<\/tr>\n
            \u7ea6\u5b9a 3<\/td>\n\u751f\u4ea7\u8005\u4e0d\u80fd\u628a\u6d88\u8d39\u8005\u5957\u4e00\u4e2a\u5708\u4ee5\u4e0a<\/td>\n\u6700\u591a\u5e76\u9a7e\u9f50\u9a71；\u5957\u4e00\u5708\u5c31\u7b49\u4e8e\u8986\u76d6\u4e86\u6240\u6709\u5386\u53f2\u6570\u636e<\/td>\n<\/tr>\n
            \u7ea6\u5b9a 4<\/td>\n\u6d88\u8d39\u8005\u4e0d\u80fd\u8d85\u8fc7\u751f\u4ea7\u8005<\/td>\n\u8d85\u8fc7\u751f\u4ea7\u8005 = \u8dd1\u5230\u524d\u9762\u53bb\u62ff，\u62ff\u5230\u7684\u5168\u662f\u65e0\u6548\u6570\u636e（\u201c\u8b66\u5bdf\u8dd1\u5230\u5c0f\u5077\u524d\u9762\u53bb\u4e86，\u8fd9\u5c31\u5f88\u6ed1\u7a3d\u201d）<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

            \u7ea6\u5b9a 3\u30014 \u5408\u8d77\u6765\u8bf4\u7684\u5176\u5b9e\u662f\u4e00\u4ef6\u4e8b：\u4e24\u4e2a\u4eba\u7684\u76f8\u5bf9\u8ddd\u79bb\u6c38\u8fdc\u4e0d\u80fd\u8d85\u8fc7\u4e00\u5708\u3002<\/p>\n

            \u2714 \u8bb0\u4f4f\u4e00\u53e5\u8bdd：\u7ea6\u5b9a 1\u30012 \u7ba1"\u8c01\u5148\u8dd1"，\u7ea6\u5b9a 3\u30014 \u7ba1"\u8c01\u4e0d\u80fd\u8d85\u8fc7\u8c01"\u3002<\/p>\n

            \n

            \u516b\u3001\u4e24\u4e2a\u7ed3\u8bba：\u4ec0\u4e48\u65f6\u5019\u53ef\u4ee5\u300c\u4e00\u8d77\u8dd1\u300d<\/h3>\n

            \u4e09\u4e2a\u95ee\u9898，\u7b54\u6848\u76f4\u63a5\u7ed9\u51fa\u7ed3\u8bba\u3002<\/p>\n

            \u601d\u8003 1：\u53ea\u8981\u4e0d\u8bbf\u95ee\u540c\u4e00\u4e2a\u4f4d\u7f6e，\u80fd\u4e0d\u80fd\u540c\u65f6\u8fdb\u884c？<\/h4>\n

            \u80fd\u3002 \u6211\u5728\u7b2c 6 \u4e2a\u4f4d\u7f6e\u653e\u82f9\u679c，\u4f60\u5728\u7b2c 1 \u4e2a\u4f4d\u7f6e\u62ff\u82f9\u679c \u2014\u2014 \u5b8c\u5168\u4e0d\u51b2\u7a81，\u751f\u4ea7\u6d88\u8d39\u53ef\u4ee5\u771f\u6b63\u540c\u65f6\u53d1\u751f\u3002<\/p>\n

            \u601d\u8003 2：\u4ec0\u4e48\u65f6\u5019\u4e24\u4e2a\u4eba\u4f1a\u6307\u5411\u540c\u4e00\u4e2a\u4f4d\u7f6e？<\/h4>\n

            \u201c\u8fd9\u4e00\u4e2a\u95ee\u9898\u53ea\u8981\u60f3\u660e\u767d\u4e86，\u73af\u5f62\u961f\u5217\u7684\u95ee\u9898\u5c31\u7406\u89e3\u4e00\u534a\u4e86\u3002\u201d<\/p>\n

            \u7b54\u6848：\u53ea\u6709\u4e24\u79cd\u60c5\u51b5 \u2014\u2014 \u4e3a\u7a7a，\u6216\u8005\u4e3a\u6ee1\u3002
            \n\u56e0\u4e3a head \u548c tail \u53ea\u6709\u5728\u4e3a\u7a7a\u548c\u4e3a\u6ee1\u65f6\u624d\u4f1a\u91cd\u5408，\u5176\u4ed6\u4efb\u4f55\u65f6\u5019\u90fd\u4e0d\u4f1a\u3002<\/p>\n

            \u601d\u8003 3：\u4e3a\u7a7a \/ \u4e3a\u6ee1\u7684\u65f6\u5019\u8c01\u5148\u8dd1？<\/h4>\n
              \n
            • \u4e3a\u7a7a \u2192 \u6d88\u8d39\u8005\u6ca1\u6cd5\u6d88\u8d39 \u2192 \u53ea\u80fd\u8ba9\u751f\u4ea7\u8005\u5148\u8fd0\u884c<\/li>\n
            • \u4e3a\u6ee1 \u2192 \u751f\u4ea7\u8005\u6ca1\u6cd5\u751f\u4ea7 \u2192 \u53ea\u80fd\u8ba9\u6d88\u8d39\u8005\u5148\u8fd0\u884c<\/li>\n<\/ul>\n

              \u6ce8\u610f\u8fd9\u4e0d\u53ea\u662f"\u5148\u540e"\u95ee\u9898，\u8fd8\u5fc5\u987b\u662f\u4e92\u65a5\u7684：\u4e0d\u80fd\u6211\u751f\u4ea7\u8005\u6b63\u5728\u751f\u4ea7\u7684\u65f6\u5019\u4f60\u5c31\u9760\u8fdb\u6765\u4e86\u3002<\/p>\n

              \u4e8e\u662f\u5f97\u5230\u4e24\u6761\u7ed3\u8bba<\/h4>\n

              \u7ed3\u8bba 1：\u73af\u5f62\u961f\u5217\u3010\u4e0d\u4e3a\u7a7a && \u4e0d\u4e3a\u6ee1\u3011 \u2192 \u751f\u4ea7\u548c\u6d88\u8d39\u53ef\u4ee5\u3010\u540c\u65f6\u8fdb\u884c\u3011！
              \n\u7ed3\u8bba 2：\u73af\u5f62\u961f\u5217\u3010\u4e3a\u7a7a || \u4e3a\u6ee1\u3011 \u2192 \u751f\u4ea7\u548c\u6d88\u8d39\u9700\u8981\u3010\u540c\u6b65 + \u4e92\u65a5\u3011！<\/p>\n

              💡 \u8fd9\u4e24\u6761\u7ed3\u8bba\u7684"\u5386\u53f2\u610f\u4e49"\u5728\u4e8e：\u5b83\u628a\u73af\u5f62\u961f\u5217\u7684\u95ee\u9898，\u4ece"\u600e\u4e48\u5224\u65ad\u7a7a\u6ee1"\u8f6c\u5316\u6210\u4e86"\u600e\u4e48\u4fdd\u8bc1\u8fd9 4 \u4e2a\u7ea6\u5b9a"\u3002
              \n\u7b54：\u7528\u4fe1\u53f7\u91cf\u6765\u4fdd\u8bc1\u3002<\/p>\n

              \n

              \u4e5d\u3001\u4fe1\u53f7\u91cf\u7684\u4e24\u5f20\u7968：sem_blank \u4e0e sem_data<\/h3>\n

              \u5728\u52a8\u624b\u5199\u4ee3\u7801\u4e4b\u524d，\u5148\u628a"\u751f\u4ea7\u8005\u5173\u5fc3\u4ec0\u4e48\u3001\u6d88\u8d39\u8005\u5173\u5fc3\u4ec0\u4e48"\u5206\u6e05\u695a\u3002<\/p>\n

              9.1 \u751f\u4ea7\u8005\u5173\u5fc3\u300c\u7a7a\u4f4d\u300d，\u6d88\u8d39\u8005\u5173\u5fc3\u300c\u6570\u636e\u300d<\/h4>\n

              \u201c\u6211\u653e\u82f9\u679c，\u4f60\u62ff\u82f9\u679c\u3002\u4f60\u5f53\u7136\u6700\u5173\u6ce8\u7684\u662f\u82f9\u679c，\u800c\u6211\u4f5c\u4e3a\u653e\u82f9\u679c\u7684\u4eba，\u6700\u5173\u6ce8\u7684\u662f\u7a7a\u76d8\u5b50\u3002\u201d<\/p>\n\n\u89d2\u8272\u5173\u5fc3\u7684\u8d44\u6e90\u4fe1\u53f7\u91cf\u521d\u503c<\/tr>\n\n\n\n
              \u751f\u4ea7\u8005<\/td>\n\u73af\u5f62\u961f\u5217\u91cc\u7a7a\u7684\u4f4d\u7f6e<\/td>\nsem_blank<\/td>\nN（\u521a\u5f00\u59cb\u5168\u7a7a）<\/td>\n<\/tr>\n
              \u6d88\u8d39\u8005<\/td>\n\u73af\u5f62\u961f\u5217\u91cc\u6709\u6548\u6570\u636e<\/td>\nsem_data<\/td>\n0（\u521a\u5f00\u59cb\u6ca1\u6570\u636e）<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

              \"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"<\/p>\n

              9.2 \u4ee3\u7801\u9aa8\u67b6<\/h4>\n

              \/\/ \u751f\u4ea7\u8005<\/span>
              \nP<\/span>(<\/span>sem_blank)<\/span>;<\/span> \/\/ \u7a7a\u4f4d\u51cf\u4e00，P \u4e0d\u5230\u5c31\u963b\u585e<\/span>
              \n\/\/ \u8d70\u5230\u8fd9\u91cc，\u4e00\u5b9a\u6709\u7a7a\u95f4！<\/span>
              \nring[<\/span>p_step]<\/span> =<\/span> data;<\/span>
              \np_step++<\/span>;<\/span> p_step %=<\/span> N;<\/span>
              \nV<\/span>(<\/span>sem_data)<\/span>;<\/span> \/\/ \u6570\u636e\u52a0\u4e00，\u901a\u77e5\u6d88\u8d39\u8005<\/span><\/p>\n

              \/\/ \u6d88\u8d39\u8005<\/span>
              \nP<\/span>(<\/span>sem_data)<\/span>;<\/span> \/\/ \u6570\u636e\u51cf\u4e00，P \u4e0d\u5230\u5c31\u963b\u585e<\/span>
              \n\/\/ \u8d70\u5230\u8fd9\u91cc，\u4e00\u5b9a\u6709\u6570\u636e！<\/span>
              \ndata =<\/span> ring[<\/span>c_step]<\/span>;<\/span>
              \nc_step++<\/span>;<\/span> c_step %=<\/span> N;<\/span>
              \nV<\/span>(<\/span>sem_blank)<\/span>;<\/span> \/\/ \u7a7a\u4f4d\u52a0\u4e00，\u901a\u77e5\u751f\u4ea7\u8005<\/span><\/p>\n

              9.3 \u5b8c\u7f8e\u5bf9\u79f0<\/h4>\n

              \u751f\u4ea7\u8005：P(\u7a7a\u4f4d) \u2192 \u751f\u4ea7 \u2192 V(\u6570\u636e)
              \n\u6d88\u8d39\u8005：P(\u6570\u636e) \u2192 \u6d88\u8d39 \u2192 V(\u7a7a\u4f4d)<\/p>\n

              \u2714 \u53cc\u65b9\u5404\u81ea P \u81ea\u5df1\u5173\u5fc3\u7684\u8d44\u6e90\u3001V \u5bf9\u65b9\u5173\u5fc3\u7684\u8d44\u6e90 \u2014\u2014 \u8fd9\u5c31\u662f\u4e24\u4e2a\u4fe1\u53f7\u91cf\u5168\u90e8\u7684\u6d41\u8f6c\u903b\u8f91\u3002
              \n\u2714 \u800c\u4e14\u6ce8\u610f\u987a\u5e8f：P \u5728\u52a0\u9501\u4e4b\u524d（\u591a\u751f\u4ea7\u591a\u6d88\u8d39\u65f6）\u3002\u5148\u9884\u5b9a\u3001\u518d\u6392\u961f \u2014\u2014 \u5224\u5b9a\u8d44\u6e90\u662f\u5426\u5c31\u7eea，\u6839\u672c\u4e0d\u9700\u8981\u52a0\u9501\u3002\u7b2c\u5341\u4e09\u8282\u4e13\u95e8\u8bba\u8bc1\u8fd9\u4e00\u70b9\u3002<\/p>\n

              \n

              \u5341\u3001\u63a5\u53e3：POSIX \u4fe1\u53f7\u91cf\u7684\u56db\u4ef6\u5957<\/h3>\n

              #<\/span>include<\/span> <semaphore.h><\/span><\/span><\/p>\n

              sem_t<\/span> sem;<\/span> \/\/ \u2460 \u7c7b\u578b：sem_t<\/span><\/p>\n

              int<\/span> sem_init<\/span>(<\/span>sem_t<\/span> *<\/span>sem,<\/span> int<\/span> pshared,<\/span> unsigned<\/span> int<\/span> value)<\/span>;<\/span> \/\/ \u2461 \u521d\u59cb\u5316<\/span>
              \n\/\/ pshared = 0 \u2192 \u7ebf\u7a0b\u95f4\u5171\u4eab（\u6211\u4eec\u4eca\u5929\u7528\u7684）<\/span>
              \n\/\/ pshared \u2260 0 \u2192 \u8fdb\u7a0b\u95f4\u5171\u4eab<\/span>
              \n\/\/ value \u2192 \u4fe1\u53f7\u91cf\u521d\u59cb\u503c（\u8ba1\u6570\u5668\u521d\u503c）<\/span><\/p>\n

              int<\/span> sem_destroy<\/span>(<\/span>sem_t<\/span> *<\/span>sem)<\/span>;<\/span> \/\/ \u2462 \u9500\u6bc1<\/span><\/p>\n

              int<\/span> sem_wait<\/span>(<\/span>sem_t<\/span> *<\/span>sem)<\/span>;<\/span> \/\/ \u2463 P \u64cd\u4f5c：\u503c\u51cf 1<\/span>
              \nint<\/span> sem_post<\/span>(<\/span>sem_t<\/span> *<\/span>sem)<\/span>;<\/span> \/\/ \u2464 V \u64cd\u4f5c：\u503c\u52a0 1<\/span><\/p>\n

              10.1 \u4e09\u4e2a\u8981\u70b9<\/h4>\n
                \n
              • sem_t \u5c31\u662f\u4e00\u4e2a\u7c7b\u578b，\u8ddf pthread_mutex_t \u4e00\u6837，\u5b9a\u4e49\u4e00\u4e2a\u5bf9\u8c61\u5c31\u662f\u4e00\u4e2a\u4fe1\u53f7\u91cf<\/li>\n
              • sem_wait = P，sem_post = V \u2014\u2014 \u540d\u5b57\u4e0d\u540c，\u8bed\u4e49\u5b8c\u5168\u4e00\u6837<\/li>\n
              • \u8fd4\u56de\u503c：0 \u8868\u793a\u6210\u529f，\u975e 0 \u8868\u793a\u5931\u8d25<\/li>\n<\/ul>\n

                10.2 \u4e3a\u4ec0\u4e48\u53ea\u9700\u8981\u91cd\u70b9\u5b66 POSIX \u8fd9\u4e00\u5957<\/h4>\n

                \u201cPOSIX \u4fe1\u53f7\u91cf\u4e3b\u8981\u7528\u6765\u505a\u7ebf\u7a0b\u95f4\u7684\u540c\u6b65\u3002\u5f53\u7136\u5982\u679c\u4f60\u60f3\u505a\u5230\u8fdb\u7a0b\u95f4\u540c\u6b65\u4e5f\u53ef\u4ee5 \u2014\u2014 \u7528\u5171\u4eab\u5185\u5b58，\u628a\u90a3\u4e2a\u5730\u5740\u5f3a\u8f6c\u6210 sem_t* \u7c7b\u578b，\u7528 sem_init \u53bb\u521d\u59cb\u5316\u5c31\u884c\u3002\u201d<\/p>\n

                \u6240\u4ee5 System V \u90a3\u4e00\u5957\u53ef\u4ee5\u4e0d\u770b\u4e86，POSIX \u8fd9\u5957\u65e2\u80fd\u505a\u7ebf\u7a0b\u4e5f\u80fd\u505a\u8fdb\u7a0b（\u914d\u5408\u5171\u4eab\u5185\u5b58）\u3002<\/p>\n

                10.3 sem_wait \u5185\u90e8\u5e72\u4e86\u4ec0\u4e48<\/h4>\n

                sem_wait<\/span>(<\/span>&<\/span>sem)<\/span>;<\/span>
                \n\/\/ \u5e95\u5c42：sem \u7684\u503c —<\/span>
                \n\/\/ \u251c\u2500 \u51cf\u5b8c >= 0 \u2192 \u7533\u8bf7\u6210\u529f，\u7ee7\u7eed\u5f80\u540e\u8d70<\/span>
                \n\/\/ \u2514\u2500 \u51cf\u5b8c < 0 \u2192 \u5f53\u524d\u7ebf\u7a0b\u88ab\u3010\u963b\u585e\u3011，\u76f4\u5230\u4fe1\u53f7\u91cf\u503c\u91cd\u65b0 > 0 \u624d\u88ab\u5524\u9192<\/span><\/p>\n

                💡 \u8fd9\u5c31\u662f"\u9884\u8ba2"：sem_wait \u8fd4\u56de\u4e86，\u8bf4\u660e\u8d44\u6e90\u4e00\u5b9a\u6709\u4f60\u7684；sem_wait \u963b\u585e\u4e86，\u8bf4\u660e\u8d44\u6e90\u8fd8\u6ca1\u5230\u4f4d，\u4f60\u8fde\u95e8\u90fd\u4e0d\u7528\u8fdb\u3002<\/p>\n

                \n

                \u5341\u4e00\u3001\u628a\u4fe1\u53f7\u91cf\u5c01\u88c5\u6210 Sem<\/h3>\n

                \/\/ Sem.hpp<\/span>
                \n#<\/span>pragma<\/span> once<\/span><\/span>
                \n#<\/span>include<\/span> <iostream><\/span><\/span>
                \n#<\/span>include<\/span> <semaphore.h><\/span><\/span><\/p>\n

                namespace<\/span> SemModule
                \n{<\/span>
                \n const<\/span> int<\/span> default_value =<\/span> 1<\/span>;<\/span><\/p>\n

                class<\/span> Sem<\/span>
                \n {<\/span>
                \n public<\/span>:<\/span>
                \n Sem<\/span>(<\/span>int<\/span> value =<\/span> default_value)<\/span> {<\/span> sem_init<\/span>(<\/span>&<\/span>_sem,<\/span> 0<\/span>,<\/span> value)<\/span>;<\/span> }<\/span> \/\/ pshared = 0<\/span>
                \n void<\/span> P<\/span>(<\/span>)<\/span> {<\/span> sem_wait<\/span>(<\/span>&<\/span>_sem)<\/span>;<\/span> }<\/span>
                \n void<\/span> V<\/span>(<\/span>)<\/span> {<\/span> sem_post<\/span>(<\/span>&<\/span>_sem)<\/span>;<\/span> }<\/span>
                \n ~<\/span>Sem<\/span>(<\/span>)<\/span> {<\/span> sem_destroy<\/span>(<\/span>&<\/span>_sem)<\/span>;<\/span> }<\/span>
                \n private<\/span>:<\/span>
                \n sem_t _sem;<\/span>
                \n }<\/span>;<\/span>
                \n}<\/span><\/p>\n

                \u2714 \u5c01\u88c5\u5b8c\u5c31\u4e09\u4ef6\u4e8b：\u6784\u9020\u7ed9\u521d\u503c\u3001P()\u3001V()\u3002
                \n\u2714 \u4e4b\u540e\u5728\u73af\u5f62\u961f\u5217\u91cc\u76f4\u63a5\u7528 Sem \u5bf9\u8c61，\u4e0d\u7528\u518d\u78b0\u88f8\u63a5\u53e3\u3002<\/p>\n

                \n

                \u5341\u4e8c\u3001\u4ee3\u7801 v1：\u5355\u751f\u4ea7\u5355\u6d88\u8d39\u7684\u73af\u5f62\u961f\u5217<\/h3>\n

                12.1 \u5148\u770b\u4e0a\u5c42\u600e\u4e48\u7528（\u81ea\u4e0a\u800c\u4e0b\u8bbe\u8ba1）<\/h4>\n

                SemModule::<\/span>Sem blank_sem<\/span>(<\/span>cap)<\/span>;<\/span> \/\/ \u6216\u8005\u76f4\u63a5\u5728 RingQueue \u5185\u90e8\u6784\u9020<\/span>
                \nRingQueue<<\/span>int<\/span>><\/span> *<\/span>rq =<\/span> new<\/span> RingQueue<\/span><<\/span>int<\/span>><\/span><\/span><\/span>(<\/span>5<\/span>)<\/span>;<\/span><\/p>\n

                pthread_create<\/span>(<\/span>&<\/span>p,<\/span> nullptr<\/span>,<\/span> producer,<\/span> rq)<\/span>;<\/span> \/\/ \u4e00\u4e2a\u751f\u4ea7\u8005<\/span>
                \npthread_create<\/span>(<\/span>&<\/span>c,<\/span> nullptr<\/span>,<\/span> consumer,<\/span> rq)<\/span>;<\/span> \/\/ \u4e00\u4e2a\u6d88\u8d39\u8005<\/span><\/p>\n

                \u751f\u4ea7\u8005\u5f80\u73af\u5f62\u961f\u5217\u91cc Enqueue，\u6d88\u8d39\u8005\u4ece\u91cc\u9762 Pop \u2014\u2014 \u4e24\u79cd\u89d2\u8272\u3001\u4e00\u4e2a\u4ea4\u6613\u573a\u6240，\u5168\u9f50\u4e86\u3002<\/p>\n

                12.2 RingQueue \u7684\u6210\u5458<\/h4>\n

                template<\/span> <<\/span>typename<\/span> T<\/span>><\/span>
                \nclass<\/span> RingQueue<\/span>
                \n{<\/span>
                \nprivate<\/span>:<\/span>
                \n std::<\/span>vector<<\/span>T><\/span> _ring_queue;<\/span> \/\/ \u5e95\u5c42\u5bb9\u5668：\u56fa\u5b9a\u957f\u5ea6\u6570\u7ec4（\u4e0d\u662f queue！）<\/span>
                \n int<\/span> _cap;<\/span> \/\/ \u5bb9\u91cf\u4e0a\u9650 N<\/span><\/p>\n

                Sem _blank_sem;<\/span> \/\/ \u751f\u4ea7\u8005\u5173\u5fc3：\u7a7a\u4f4d\u7f6e\u6570\u91cf，\u521d\u503c = N<\/span>
                \n Sem _data_sem;<\/span> \/\/ \u6d88\u8d39\u8005\u5173\u5fc3：\u6570\u636e\u6570\u91cf， \u521d\u503c = 0<\/span><\/p>\n

                int<\/span> _p_step;<\/span> \/\/ \u751f\u4ea7\u8005\u4e0b\u6807，\u521d\u503c 0<\/span>
                \n int<\/span> _c_step;<\/span> \/\/ \u6d88\u8d39\u8005\u4e0b\u6807，\u521d\u503c 0<\/span>
                \n}<\/span>;<\/span><\/p>\n

                💡 \u4e3a\u4ec0\u4e48\u7528 vector \u800c\u4e0d\u662f queue？ \u56e0\u4e3a\u8981\u80fd\u6309\u4e0b\u6807\u968f\u673a\u8bbf\u95ee（_ring_queue[i] = in）\u3002
                \nqueue \u53ea\u80fd push \/ front \/ pop，\u62ff\u4e0d\u5230\u4e0b\u6807，\u4e5f\u505a\u4e0d\u4e86"\u4e24\u4e2a\u7ebf\u7a0b\u8bbf\u95ee\u4e0d\u540c\u4f4d\u7f6e"\u8fd9\u4ef6\u4e8b \u2014\u2014 \u8fd9\u6b63\u662f\u5b83\u53ea\u80fd\u6574\u4f53\u4f7f\u7528\u7684\u539f\u56e0\u3002<\/p>\n

                12.3 \u4e24\u4e2a\u63a5\u53e3（v1：\u65e0\u9501）<\/h4>\n

                void<\/span> Enqueue<\/span>(<\/span>const<\/span> T &<\/span>in)<\/span> \/\/ \u751f\u4ea7\u8005<\/span>
                \n{<\/span>
                \n _blank_sem.<\/span>P<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2460 \u7533\u8bf7\u7a7a\u4f4d（\u6ca1\u6709\u5c31\u963b\u585e）<\/span>
                \n _ring_queue[<\/span>_p_step++<\/span>]<\/span> =<\/span> in;<\/span> \/\/ \u2461 \u4e00\u5b9a\u6709\u4f4d\u7f6e，\u76f4\u63a5\u751f\u4ea7<\/span>
                \n _p_step %=<\/span> _cap;<\/span> \/\/ \u2462 \u7ef4\u6301\u73af\u5f62\u7279\u6027<\/span>
                \n _data_sem.<\/span>V<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2463 \u6570\u636e +1，\u901a\u77e5\u6d88\u8d39\u8005<\/span>
                \n}<\/span><\/p>\n

                void<\/span> Pop<\/span>(<\/span>T *<\/span>out)<\/span> \/\/ \u6d88\u8d39\u8005<\/span>
                \n{<\/span>
                \n _data_sem.<\/span>P<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2460 \u7533\u8bf7\u6570\u636e（\u6ca1\u6709\u5c31\u963b\u585e）<\/span>
                \n *<\/span>out =<\/span> _ring_queue[<\/span>_c_step++<\/span>]<\/span>;<\/span> \/\/ \u2461 \u4e00\u5b9a\u6709\u6570\u636e，\u76f4\u63a5\u53d6\u8d70<\/span>
                \n _c_step %=<\/span> _cap;<\/span> \/\/ \u2462 \u7ef4\u6301\u73af\u5f62\u7279\u6027<\/span>
                \n _blank_sem.<\/span>V<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2463 \u7a7a\u4f4d +1，\u901a\u77e5\u751f\u4ea7\u8005<\/span>
                \n}<\/span><\/p>\n

                12.4 \u5355\u751f\u4ea7\u5355\u6d88\u8d39\u4e3a\u4ec0\u4e48\u4e0d\u9700\u8981\u52a0\u9501<\/h4>\n

                \u201c\u4ed6\u4eec\u4e24\u4e2a\u4ece\u751f\u4ea7\u5230\u6d88\u8d39\u7684\u8fc7\u7a0b\u90fd\u662f\u539f\u5b50\u7684，\u6ca1\u6709\u4eba\u5e72\u6270\u6211 \u2014\u2014 \u5c24\u5176\u662f\u5355\u751f\u4ea7\u5355\u6d88\u8d39\u3002\u53ea\u6709\u5f53\u5b83\u4fe9\u8bbf\u95ee\u540c\u4e00\u4e2a\u4f4d\u7f6e\u65f6\u624d\u4f1a\u51fa\u73b0\u7ade\u4e89，\u90a3\u4e00\u523b\u7528\u4fe1\u53f7\u91cf\u6765\u4fdd\u8bc1\u4e92\u65a5\u4e0e\u540c\u6b65；\u4e0d\u8bbf\u95ee\u540c\u4e00\u4f4d\u7f6e\u65f6，\u6211\u4eec\u4e92\u4e0d\u5e72\u6270\u3002\u201d<\/p>\n

                \u800c\u4ec0\u4e48\u65f6\u5019\u4f1a\u8bbf\u95ee\u540c\u4e00\u4e2a\u4f4d\u7f6e？\u53ea\u6709\u4e3a\u7a7a\u6216\u4e3a\u6ee1\u7684\u65f6\u5019 \u2014\u2014 \u800c\u90a3\u4e24\u4e2a\u65f6\u523b，\u4fe1\u53f7\u91cf\u5df2\u7ecf\u628a\u5176\u4e2d\u4e00\u4e2a\u7ebf\u7a0b\u6321\u4f4f\u4e86（sem \u503c\u4e3a 0，P \u4e0d\u8fc7\u53bb）\u3002\u6240\u4ee5\u51b2\u7a81\u6839\u672c\u4e0d\u4f1a\u53d1\u751f\u3002<\/p>\n

                12.5 \u8dd1\u8d77\u6765\u770b\u73b0\u8c61<\/h4>\n

                \u5b9e\u9a8c\u4e00：\u751f\u4ea7\u8005\u5feb\u3001\u6d88\u8d39\u8005\u6162（\u6bcf 2 \u79d2\u6d88\u8d39\u4e00\u4e2a）<\/p>\n

                \u751f\u4ea7 1 2 3 4 5 \u2190 \u4e00\u77ac\u95f4\u628a\u961f\u5217\u6253\u6ee1（cap = 5）
                \n（\u751f\u4ea7\u8005\u963b\u585e：blank_sem \u5df2\u7ecf 0）
                \n\u6d88\u8d39 1 \u2190 2 \u79d2\u540e
                \n\u751f\u4ea7 6 \u2190 \u7a7a\u51fa\u4e00\u4e2a\u4f4d\u7f6e，\u7acb\u523b\u8865\u4e0a
                \n\u6d88\u8d39 2
                \n\u751f\u4ea7 7
                \n\u6d88\u8d39 3
                \n…<\/p>\n

                \u2714 \u73b0\u8c61：\u4e00\u77ac\u95f4\u62c9\u6ee1，\u4e4b\u540e"\u6d88\u8d39\u4e00\u4e2a\u3001\u751f\u4ea7\u4e00\u4e2a"，\u4e25\u683c\u4ea4\u66ff \u2014\u2014 \u8fd9\u5c31\u662f\u540c\u6b65\u88ab\u53ef\u89c6\u5316\u4e86\u3002<\/p>\n

                \u5b9e\u9a8c\u4e8c：\u751f\u4ea7\u8005\u6162\u3001\u6d88\u8d39\u8005\u5feb<\/p>\n

                \u6d88\u8d39\u8005\u4e00\u4e0a\u6765\u5c31 P(data_sem) \u2192 \u503c\u4e3a 0 \u2192 \u76f4\u63a5\u963b\u585e
                \n\u751f\u4ea7 1 \u2192 \u6d88\u8d39 1 \u2192 \u751f\u4ea7 2 \u2192 \u6d88\u8d39 2 …<\/p>\n

                \u2714 \u73b0\u8c61：\u751f\u4ea7\u8005"\u751f\u4ea7\u4e00\u4e2a"，\u6d88\u8d39\u8005\u624d"\u80fd\u6d88\u8d39\u4e00\u4e2a" \u2014\u2014 \u6d88\u8d39\u8005\u88ab\u7a7a\u961f\u5217\u5361\u4f4f\u4e86\u3002<\/p>\n

                💡 \u8fd9\u4e24\u7ec4\u5b9e\u9a8c\u7684\u552f\u4e00\u76ee\u7684：\u8ba9\u4f60\u8089\u773c\u770b\u5230\u540c\u6b65\u3002\u771f\u5b9e\u9ad8\u5e76\u53d1\u8dd1\u8d77\u6765，\u4e24\u4e2a\u7ebf\u7a0b\u5c31\u662f\u5404\u79cd\u4ea4\u53c9，\u770b\u4e0d\u51fa\u6765\u4e86\u3002<\/p>\n

                \n

                \u5341\u4e09\u3001\u2605 \u5148\u52a0\u9501\u8fd8\u662f\u5148 P？\u2014\u2014\u7535\u5f71\u9662\u4e70\u7968\u7684\u7b2c\u4e8c\u8bfe<\/h3>\n

                \u5355\u751f\u4ea7\u5355\u6d88\u8d39\u4e0d\u9700\u8981\u9501\u3002\u4f46\u4e00\u65e6\u6269\u5230\u591a\u751f\u4ea7\u591a\u6d88\u8d39，\u5c31\u5fc5\u987b\u52a0\u9501\u3002\u4e8e\u662f\u95ee\u9898\u6765\u4e86：<\/p>\n

                \/\/ \u5199\u6cd5 1：\u5148\u52a0\u9501，\u518d P<\/span>
                \nmutex.<\/span>Lock<\/span>(<\/span>)<\/span>;<\/span>
                \nsem.<\/span>P<\/span>(<\/span>)<\/span>;<\/span>
                \n.<\/span>.<\/span>.<\/span>
                \nsem.<\/span>V<\/span>(<\/span>)<\/span>;<\/span>
                \nmutex.<\/span>Unlock<\/span>(<\/span>)<\/span>;<\/span><\/p>\n

                \/\/ \u5199\u6cd5 2：\u5148 P，\u518d\u52a0\u9501<\/span>
                \nsem.<\/span>P<\/span>(<\/span>)<\/span>;<\/span>
                \nmutex.<\/span>Lock<\/span>(<\/span>)<\/span>;<\/span>
                \n.<\/span>.<\/span>.<\/span>
                \nmutex.<\/span>Unlock<\/span>(<\/span>)<\/span>;<\/span>
                \nsem.<\/span>V<\/span>(<\/span>)<\/span>;<\/span><\/p>\n

                13.1 \u5148\u52a0\u9501\u9519\u5417？\u2014\u2014 \u4e0d\u9519，\u4f46\u4f4e\u6548<\/h4>\n

                \u56e0\u4e3a\u52a0\u9501\u5c31\u662f\u5728\u7ef4\u62a4\u4e92\u65a5\u5173\u7cfb：\u591a\u4e2a\u751f\u4ea7\u8005\u5148\u81ea\u5df1\u4e89\u51fa\u4e00\u4e2a\u80dc\u5229\u8005，\u518d\u7531\u8fd9\u4e2a\u80dc\u5229\u8005\u53bb\u548c\u6d88\u8d39\u8005\u7ade\u4e89 \u2014\u2014 \u903b\u8f91\u4e0a\u6ca1\u6bdb\u75c5\u3002<\/p>\n

                13.2 \u4f46\u6548\u7387\u5dee\u5728\u54ea：\u770b\u7535\u5f71\u7684\u4e24\u79cd\u6392\u961f\u65b9\u5f0f<\/h4>\n

                \u65b9\u5f0f A（\u5148\u52a0\u9501）：\u6240\u6709\u4eba\u5728\u7535\u5f71\u9662\u95e8\u53e3\u6392\u961f，\u4e00\u4e2a\u4e2a\u8fdb\u53bb\u68c0\u7968，\u8f6e\u5230\u4f60\u624d\u638f\u624b\u673a\u4e70\u7968\u3002\u4e70\u5230\u4e86\u8fdb\u53bb，\u4e70\u5931\u8d25\u4e86\u5927\u5bb6\u4e00\u8d77\u7b49\u3002<\/p>\n

                \u65b9\u5f0f B（\u5148 P）：\u6240\u6709\u4eba\u5148\u628a\u7968\u62a2\u4e86，\u6ca1\u62a2\u5230\u7968\u7684\u4eba\u8fde\u6392\u961f\u7684\u8d44\u683c\u90fd\u6ca1\u6709；\u62a2\u5230\u7968\u7684\u4eba\u518d\u4f9d\u6b21\u5728\u95e8\u53e3\u6392\u961f\u5165\u573a\u3002<\/p>\n

                \u54ea\u79cd\u6548\u7387\u9ad8？\u660e\u663e\u662f B\u3002<\/p>\n

                13.3 \u4e3a\u4ec0\u4e48 B \u66f4\u5feb<\/h4>\n\n\u5148\u52a0\u9501（A）\u5148 P（B）<\/tr>\n\n\n\n\n
                \u9501\u7684\u4f5c\u7528\u8303\u56f4<\/td>\n\u5305\u542b\u4e86"\u7533\u8bf7\u8d44\u6e90"\u8fd9\u4e00\u6b65<\/td>\n\u53ea\u5305\u542b"\u8bbf\u95ee\u8d44\u6e90"\u8fd9\u4e00\u6b65<\/td>\n<\/tr>\n
                \u6392\u961f\u7b49\u5f85\u7684\u7ebf\u7a0b\u5728\u5e72\u4ec0\u4e48<\/td>\n\u5e72\u7b49，\u4ec0\u4e48\u90fd\u6ca1\u505a<\/td>\n\u5df2\u7ecf\u5728\u539f\u5b50\u5730\u7533\u8bf7\u4fe1\u53f7\u91cf，\u628a\u8d44\u6e90\u51c6\u5907\u597d\u4e86<\/td>\n<\/tr>\n
                \u5173\u952e\u5dee\u5f02<\/td>\n\u62a2\u5230\u9501\u7684\u4eba\u6162\u6162\u7533\u8bf7\u8d44\u6e90，\u5176\u4ed6\u4eba\u5e72\u7b49<\/td>\n\u8d44\u6e90\u88ab\u4e00\u6b21\u6027\u74dc\u5206，\u5927\u5bb6\u624b\u6301\u95e8\u7968\u6392\u961f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                \u2714 \u800c\u4e14\u4fe1\u53f7\u91cf\u4e0d\u4f1a\u8d85\u7533\u8bf7：sem \u521d\u503c\u662f\u51e0，\u6700\u591a\u5c31\u653e\u51e0\u4e2a\u7ebf\u7a0b\u8fdb\u6765\u3002\u8fd9\u4e2a"\u9650\u6d41"\u662f\u539f\u5b50\u5b8c\u6210\u7684，\u4e0d\u9700\u8981\u9501\u4fdd\u62a4\u3002<\/p>\n

                \u8001\u5e08\u7ed3\u8bba：\u5148\u7528\u4fe1\u53f7\u91cf\u628a\u8d44\u6e90\u74dc\u5206\u6389，\u518d\u8ba9\u62ff\u5230\u8d44\u6e90\u7684\u4eba\u4e00\u4e2a\u4e2a\u8fdb\u6765\u3002\u8c01\u62ff\u7740\u4fe1\u53f7\u91cf，\u8c01\u5c31\u4e00\u5b9a\u80fd\u8bbf\u95ee；\u8bbf\u95ee\u8fc7\u7a0b\u4e00\u5b9a\u662f\u8fde\u7eed\u7684，\u56e0\u4e3a\u52a0\u9501\u4e86，\u6ca1\u4eba\u6253\u6270\u4f60\u3002<\/p>\n

                13.4 \u7ed3\u8bba<\/h4>\n

                \u6b63\u786e\u987a\u5e8f：\u5148 P（\u9884\u5b9a\u8d44\u6e90），\u540e Lock（\u6392\u961f\u8fdb\u5165）\u3002<\/p>\n

                💡 \u6362\u4e2a\u8bf4\u6cd5\u5c31\u662f\u672c\u6587\u7b2c\u56db\u8282\u7684\u90a3\u53e5\u8bdd：\u628a"\u8d44\u6e90\u591f\u4e0d\u591f"\u7684\u5224\u5b9a，\u63d0\u524d\u5230\u8bbf\u95ee\u4e34\u754c\u8d44\u6e90\u4e4b\u524d\u3002<\/p>\n

                \n

                \u5341\u56db\u3001\u4ee3\u7801 v2：\u591a\u751f\u4ea7\u591a\u6d88\u8d39，\u6539\u4e86\u54ea\u91cc<\/h3>\n

                14.1 \u6307\u5bfc\u601d\u60f3：\u7f3a\u4ec0\u4e48\u8865\u4ec0\u4e48<\/h4>\n

                \u6309 321 \u539f\u5219\u76d8\u70b9\u4e00\u4e0b v1 \u5df2\u7ecf\u7ef4\u62a4\u4e86\u54ea\u4e9b\u5173\u7cfb：<\/p>\n\n\u5173\u7cfbv1（\u5355\u751f\u4ea7\u5355\u6d88\u8d39）v2（\u591a\u751f\u4ea7\u591a\u6d88\u8d39）<\/tr>\n\n\n\n\n
                \u751f\u4ea7\u8005 \u2014 \u751f\u4ea7\u8005<\/td>\n\u4e0d\u5b58\u5728（\u53ea\u6709\u4e00\u4e2a）<\/td>\n\u2716 \u7f3a，\u8981\u52a0\u9501<\/td>\n<\/tr>\n
                \u6d88\u8d39\u8005 \u2014 \u6d88\u8d39\u8005<\/td>\n\u4e0d\u5b58\u5728（\u53ea\u6709\u4e00\u4e2a）<\/td>\n\u2716 \u7f3a，\u8981\u52a0\u9501<\/td>\n<\/tr>\n
                \u751f\u4ea7\u8005 \u2014 \u6d88\u8d39\u8005<\/td>\n\u2714 \u4fe1\u53f7\u91cf\u5df2\u4fdd\u8bc1<\/td>\n\u2714 \u4e0d\u53d8<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                \u201c\u5f53\u4f60\u660e\u767d\u4e86\u751f\u4ea7\u8005\u6d88\u8d39\u8005\u6a21\u578b，\u4f60\u73b0\u5728\u5c31\u77e5\u9053\u4ee3\u7801\u91cc\u7f3a\u4ec0\u4e48 \u2014\u2014 \u7f3a\u751f\u4ea7\u8005\u548c\u751f\u4ea7\u8005\u4e4b\u95f4\u3001\u6d88\u8d39\u8005\u548c\u6d88\u8d39\u8005\u4e4b\u95f4\u7684\u4e92\u65a5\u5173\u7cfb\u3002\u201d<\/p>\n

                14.2 \u52a0\u4e24\u628a\u9501<\/h4>\n

                Mutex _p_mutex;<\/span> \/\/ \u7ef4\u62a4\u3010\u751f\u4ea7\u8005\u4e4b\u95f4\u3011\u7684\u4e92\u65a5<\/span>
                \nMutex _c_mutex;<\/span> \/\/ \u7ef4\u62a4\u3010\u6d88\u8d39\u8005\u4e4b\u95f4\u3011\u7684\u4e92\u65a5<\/span><\/p>\n

                \u2714 \u4e3a\u4ec0\u4e48\u662f\u4e24\u628a\u800c\u4e0d\u662f\u4e00\u628a？
                \n\u4e00\u628a\u4e5f\u80fd\u4fdd\u8bc1\u4e92\u65a5，\u4f46\u4f1a\u628a\u751f\u4ea7\u8005\u548c\u6d88\u8d39\u8005\u4e92\u76f8\u4e32\u8d77\u6765（\u751f\u4ea7\u8005\u6301\u9501\u65f6\u6d88\u8d39\u8005\u4e5f\u8fdb\u4e0d\u6765），\u5e76\u53d1\u5ea6\u767d\u767d\u964d\u4f4e\u3002\u5206\u6210\u4e24\u628a，\u5404\u7ba1\u5404\u7684\u3002<\/p>\n

                14.3 \u6700\u7ec8\u7248\u4ee3\u7801<\/h4>\n

                void<\/span> Enqueue<\/span>(<\/span>const<\/span> T &<\/span>in)<\/span> \/\/ \u751f\u4ea7\u8005<\/span>
                \n{<\/span>
                \n _blank_sem.<\/span>P<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2460 \u5148\u74dc\u5206\u8d44\u6e90（\u539f\u5b50\u5224\u5b9a）<\/span>
                \n _p_mutex.<\/span>Lock<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2461 \u518d\u6392\u961f（\u751f\u4ea7\u8005\u4e4b\u95f4\u4e92\u65a5）<\/span>
                \n _ring_queue[<\/span>_p_step++<\/span>]<\/span> =<\/span> in;<\/span> \/\/ \u2462 \u751f\u4ea7（\u4e00\u5b9a\u6709\u4f4d\u7f6e）<\/span>
                \n _p_step %=<\/span> _cap;<\/span>
                \n _p_mutex.<\/span>Unlock<\/span>(<\/span>)<\/span>;<\/span>
                \n _data_sem.<\/span>V<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2463 \u901a\u77e5\u6d88\u8d39\u8005<\/span>
                \n}<\/span><\/p>\n

                void<\/span> Pop<\/span>(<\/span>T *<\/span>out)<\/span> \/\/ \u6d88\u8d39\u8005<\/span>
                \n{<\/span>
                \n _data_sem.<\/span>P<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2460 \u5148\u74dc\u5206\u8d44\u6e90<\/span>
                \n _c_mutex.<\/span>Lock<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2461 \u518d\u6392\u961f（\u6d88\u8d39\u8005\u4e4b\u95f4\u4e92\u65a5）<\/span>
                \n *<\/span>out =<\/span> _ring_queue[<\/span>_c_step++<\/span>]<\/span>;<\/span> \/\/ \u2462 \u6d88\u8d39（\u4e00\u5b9a\u6709\u6570\u636e）<\/span>
                \n _c_step %=<\/span> _cap;<\/span>
                \n _c_mutex.<\/span>Unlock<\/span>(<\/span>)<\/span>;<\/span>
                \n _blank_sem.<\/span>V<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2463 \u901a\u77e5\u751f\u4ea7\u8005<\/span>
                \n}<\/span><\/p>\n

                💡 V \u653e\u5728\u89e3\u9501\u4e4b\u524d\u8fd8\u662f\u4e4b\u540e\u90fd\u53ef\u4ee5\u3002\u8bfe\u4ef6\u91cc\u653e\u5728\u89e3\u9501\u4e4b\u540e（\u5148 Unlock \u518d V），\u201c\u751f\u4ea7\u5b8c\u4e4b\u540e V，\u7136\u540e\u518d\u91ca\u653e\u9501\u201d（\u653e\u9501\u5185）\u2014\u2014 \u4e24\u79cd\u90fd\u5bf9，\u56e0\u4e3a V \u53ea\u662f\u628a\u8ba1\u6570\u5668\u52a0\u4e00，\u4e0d\u6d89\u53ca\u4e34\u754c\u533a\u3002<\/p>\n

                \n

                \u5341\u4e94\u3001\u2605 \u53cd\u5411\u7406\u89e3：\u4e3a\u4ec0\u4e48\u4fe1\u53f7\u91cf\u7684\u4ee3\u7801\u91cc\u5b8c\u5168\u6ca1\u6709\u5224\u65ad？<\/h3>\n

                \u8fd9\u662f\u6574\u8282\u8bfe\u6700\u60f3\u8ba9\u4f60\u60f3\u901a\u7684\u4e00\u95ee\u3002<\/p>\n

                \u628a\u4e24\u4efd\u4ee3\u7801\u6446\u5728\u4e00\u8d77\u770b：<\/p>\n

                \/\/ \u25c0 \u4e0a\u4e00\u7ae0：\u6761\u4ef6\u53d8\u91cf\u7248（\u6709\u5224\u65ad）<\/span>
                \npthread_mutex_lock<\/span>(<\/span>&<\/span>_mutex)<\/span>;<\/span>
                \nwhile<\/span> (<\/span>IsFull<\/span>(<\/span>)<\/span>)<\/span> {<\/span> \/\/ \u2190 \u5728\u3010\u4e34\u754c\u533a\u5185\u90e8\u3011\u5224\u65ad<\/span>
                \n pthread_cond_wait<\/span>(<\/span>&<\/span>_product_cond,<\/span> &<\/span>_mutex)<\/span>;<\/span>
                \n}<\/span>
                \n_block_queue.<\/span>push<\/span>(<\/span>in)<\/span>;<\/span>
                \npthread_mutex_unlock<\/span>(<\/span>&<\/span>_mutex)<\/span>;<\/span><\/p>\n

                \/\/ \u25b6 \u4eca\u5929：\u4fe1\u53f7\u91cf\u7248（\u6ca1\u6709\u5224\u65ad）<\/span>
                \n_blank_sem.<\/span>P<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u2190 \u5224\u5b9a\u88ab\u585e\u8fdb\u4e86\u8fd9\u4e00\u53e5\u91cc<\/span>
                \n_ring_queue[<\/span>_p_step++<\/span>]<\/span> =<\/span> in;<\/span><\/p>\n

                15.1 \u5224\u5b9a\u53bb\u54ea\u4e86？<\/h4>\n

                \u201c\u56e0\u4e3a\u4fe1\u53f7\u91cf\u672c\u6765\u5c31\u662f\u7528\u6765\u63cf\u8ff0\u4e34\u754c\u8d44\u6e90\u6570\u91cf\u7684\u3002\u4fe1\u53f7\u91cf\u7533\u8bf7\u5931\u8d25，\u5c31\u662f\u6761\u4ef6\u4e0d\u6ee1\u8db3\u3002\u201d<\/p>\n\n\u6761\u4ef6\u53d8\u91cf\u7248\u4fe1\u53f7\u91cf\u7248<\/tr>\n\n\n\n\n\n
                \u5224\u5b9a\u8bed\u53e5<\/td>\nwhile (IsFull())<\/td>\n\u6ca1\u6709<\/td>\n<\/tr>\n
                \u5224\u5b9a\u5728\u54ea<\/td>\n\u9501\u5185（\u4e34\u754c\u533a\u91cc）<\/td>\n\u9501\u5916（P \u64cd\u4f5c\u5185\u90e8）<\/td>\n<\/tr>\n
                \u5224\u5b9a\u5f62\u5f0f<\/td>\n\u8bfb\u5171\u4eab\u53d8\u91cf + \u6bd4\u8f83<\/td>\n\u539f\u5b50\u5730\u5bf9\u8ba1\u6570\u5668\u51cf\u4e00<\/td>\n<\/tr>\n
                \u963b\u585e\u65b9\u5f0f<\/td>\ncond_wait（\u6302\u5230\u6761\u4ef6\u53d8\u91cf\u961f\u5217）<\/td>\nP \u51cf\u5230\u8d1f\u6570（\u6302\u5230\u4fe1\u53f7\u91cf\u7b49\u5f85\u961f\u5217）<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                \u2714 \u4e24\u8005\u672c\u8d28\u5b8c\u5168\u4e00\u6837，\u53ea\u662f"\u5224\u5b9a\u8d44\u6e90\u662f\u5426\u5c31\u7eea"\u8fd9\u4ef6\u4e8b\u4ece\u9501\u5185\u642c\u5230\u4e86\u9501\u5916\u3002<\/p>\n

                15.2 \u8fd9\u5c31\u662f"\u4fe1\u53f7\u91cf\u7684\u53e6\u4e00\u4e2a\u672c\u8d28"<\/h4>\n

                \"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\"<\/p>\n

                \u4fe1\u53f7\u91cf\u628a\u5bf9\u300c\u4e34\u754c\u8d44\u6e90\u662f\u5426\u5b58\u5728\u300d\u7684\u5224\u5b9a，\u4ee5\u539f\u5b50\u6027\u7684\u5f62\u5f0f，\u5448\u73b0\u5728\u8bbf\u95ee\u4e34\u754c\u8d44\u6e90\u4e4b\u524d\u5c31\u5b8c\u6210\u4e86\u3002<\/p>\n

                \u8fd9\u53e5\u8bdd\u662f\u672c\u7ae0\u7684\u6700\u9ad8\u603b\u7ed3\u3002\u5b83\u7684\u4e09\u4e2a\u542b\u4e49：<\/p>\n

              • \u5224\u5b9a\u63d0\u524d\u4e86 \u2014\u2014 \u4e0d\u7528\u5148\u8fdb\u4e34\u754c\u533a\u518d\u770b\u6709\u6ca1\u6709\u8d44\u6e90，\u95e8\u53e3\u5c31\u62e6\u4f4f\u4e86<\/li>\n
              • \u5224\u5b9a\u539f\u5b50\u4e86 \u2014\u2014 \u51cf\u4e00\u8fd9\u4e2a\u52a8\u4f5c\u4e0d\u53ef\u5206\u5272，\u4e0d\u4f1a\u51fa\u73b0\u4e24\u4e2a\u7ebf\u7a0b\u90fd\u5224\u5b9a\u6210\u529f<\/li>\n
              • \u5224\u5b9a\u548c\u8bbf\u95ee\u5206\u79bb\u4e86 \u2014\u2014 \u6240\u4ee5\u53ef\u4ee5\u5148 P \u540e\u52a0\u9501，\u9501\u53ea\u4fdd\u62a4"\u8bbf\u95ee"\u8fd9\u4e00\u6bb5<\/li>\n

                15.3 \u90a3\u80fd\u4e0d\u80fd\u7528\u300c\u9501 + \u6761\u4ef6\u53d8\u91cf\u300d\u5b9e\u73b0\u73af\u5f62\u961f\u5217？<\/h4>\n

                \u80fd，\u5b8c\u5168\u53ef\u4ee5\u3002 \u4f46\u6ca1\u5fc5\u8981 \u2014\u2014 \u6709\u66f4\u8d34\u5408\u573a\u666f\u7684\u5de5\u5177\u3002<\/p>\n

                15.4 \u4e3a\u4ec0\u4e48\u8fd9\u4e2a\u573a\u666f\u80fd\u7528\u4fe1\u53f7\u91cf，\u4e0a\u4e00\u4e2a\u573a\u666f\u4e0d\u80fd？<\/h4>\n

                \u56de\u7b54\u662f\u5173\u952e：<\/p>\n

                \u201c\u56e0\u4e3a\u4eca\u5929\u7684\u73af\u5f62\u961f\u5217，\u662f\u6211\u4eec\u81ea\u5df1\u5b9a\u4e49\u6210\u56fa\u5b9a\u5927\u5c0f\u7684，\u6211\u4eec\u81ea\u5df1\u7528\u81ea\u5df1\u7684\u4e0b\u6807\u53bb\u8bbf\u95ee，\u628a\u5b83\u7684\u8d44\u6e90\u770b\u6210\u4e86\u4e00\u5c0f\u5757\u4e00\u5c0f\u5757\u3002
                \n\u800c\u4e0a\u4e00\u7ae0\u7684\u963b\u585e\u961f\u5217，\u6211\u4eec\u628a\u5b83\u770b\u6210\u4e00\u4e2a\u6574\u4f53 \u2014\u2014 \u5012\u4e0d\u662f\u8bf4\u6211\u4eec\u60f3\u628a\u5b83\u770b\u6210\u6574\u4f53，\u800c\u662f\u5b83\u53ea\u80fd\u88ab\u770b\u6210\u4e00\u4e2a\u6574\u4f53，\u56e0\u4e3a\u90a3\u4e2a\u961f\u5217\u4f1a\u81ea\u52a8\u6269\u5bb9，\u91cc\u9762\u8fd8\u6709\u5404\u79cd\u7c7b\u5185\u6210\u5458\u3002\u201d<\/p>\n\n\u963b\u585e\u961f\u5217（std::queue）\u73af\u5f62\u961f\u5217（vector + \u4e0b\u6807）<\/tr>\n\n\n\n\n\n
                \u80fd\u5426\u6309\u4e0b\u6807\u5207\u5206<\/td>\n\u2716 \u4e0d\u80fd（\u53ea\u80fd push\/pop）<\/td>\n\u2714 \u80fd（ring[i]）<\/td>\n<\/tr>\n
                \u4f1a\u4e0d\u4f1a\u81ea\u52a8\u6269\u5bb9<\/td>\n\u2714 \u4f1a（\u6269\u5bb9\u65f6 pop \u4f1a\u5931\u8d25）<\/td>\n\u2716 \u56fa\u5b9a\u957f\u5ea6<\/td>\n<\/tr>\n
                \u53ea\u80fd\u6574\u4f53\u4f7f\u7528？<\/td>\n\u2714 \u662f<\/td>\n\u2716 \u4e0d\u662f<\/td>\n<\/tr>\n
                \u9002\u914d\u7684\u6280\u672f<\/td>\nmutex（\u6216\u4e8c\u5143\u4fe1\u53f7\u91cf）<\/td>\n\u591a\u5143\u4fe1\u53f7\u91cf<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
                \n

                \u5341\u516d\u3001\u9000\u5316：sem \u521d\u503c\u4e3a 1 \u65f6，\u5b83\u5c31\u662f\u4e92\u65a5\u9501<\/h3>\n

                \u6700\u540e\u4e00\u4e2a\u601d\u8003\u9898：<\/p>\n

                \u5982\u679c\u73af\u5f62\u961f\u5217\u7684\u5bb9\u91cf\u4e0d\u662f N \u800c\u662f 1，\u4f1a\u53d1\u751f\u4ec0\u4e48？<\/p>\n

                \u7b54\u6848\u662f\u9000\u5316：<\/p>\n

                  \n
                • \u6570\u7ec4\u53ea\u6709 1 \u4e2a\u5143\u7d20 \u2192 \u751f\u4ea7\u8005\u4e0b\u6807\u548c\u6d88\u8d39\u8005\u4e0b\u6807\u6c38\u8fdc\u662f\u540c\u4e00\u4e2a<\/li>\n
                • sem_blank = 1\u3001sem_data = 0<\/li>\n
                • \u7167\u6837 P \/ V \/ P \/ V \u8dd1，\u4f46\u5b83\u5df2\u7ecf\u4e0d\u662f\u5e76\u53d1\u4e86，\u800c\u662f\u4e32\u884c\u7684<\/li>\n<\/ul>\n

                  \u201c\u8fd9\u4e0d\u5c31\u662f\u4e92\u65a5\u9501\u4e86\u5417？\u8fd9\u4e0d\u5c31\u662f\u4f60\u7684\u73af\u5f62\u961f\u5217\u5f53\u4e2d\u53ea\u6709\u4e00\u5757，\u9000\u5316\u6210\u6211\u4eec\u4e0a\u4e00\u7ae0\u8bb2\u7684\u963b\u585e\u961f\u5217\u4e86\u5417？\u201d<\/p>\n

                  16.1 \u7531\u6b64\u5f97\u5230\u7684\u7b2c\u4e8c\u4e2a\u6536\u83b7<\/h4>\n

                  \u2714 \u4e8c\u5143\u4fe1\u53f7\u91cf\u4e5f\u80fd\u5b9e\u73b0"\u6574\u4f53\u4f7f\u7528"\u7684\u540c\u6b65\u4e92\u65a5 \u2014\u2014 \u800c\u4e14\u5929\u7136\u5e26\u4e92\u76f8\u901a\u77e5：<\/p>\n

                  \u751f\u4ea7\u8005：P(blank=1) \u2192 \u751f\u4ea7 \u2192 V(data=1)
                  \n\u6d88\u8d39\u8005：P(data=1) \u2192 \u6d88\u8d39 \u2192 V(blank=1)<\/p>\n

                  \u201c\u6211\u751f\u4ea7\u5b8c\u901a\u77e5\u4f60，\u4f60\u6d88\u8d39\u5b8c\u901a\u77e5\u6211 \u2014\u2014 \u7528\u4e8c\u5143\u4fe1\u53f7\u91cf\u5c31\u53ef\u4ee5\u5bf9\u4e00\u4e2a\u5927\u8d44\u6e90\u6574\u4f53\u4f7f\u7528，\u800c\u4e14\u8fd8\u80fd\u4e92\u76f8\u901a\u77e5\u3002\u201d<\/p>\n

                  \u8fd9\u6b63\u662f\u7b2c\u56db\u8282\u90a3\u5f20\u9009\u578b\u8868\u7684\u95ed\u73af：\u6574\u4f53\u4f7f\u7528 \u2192 mutex \/ \u4e8c\u5143\u4fe1\u53f7\u91cf；\u5206\u5757\u4f7f\u7528 \u2192 \u591a\u5143\u4fe1\u53f7\u91cf\u3002<\/p>\n

                  \n

                  \u5341\u4e03\u3001\u603b\u7ed3\u901f\u67e5\u8868<\/h3>\n\n\u95ee\u9898\u7b54\u6848<\/tr>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
                  \u4fe1\u53f7\u548c\u4fe1\u53f7\u91cf\u6709\u5173\u7cfb\u5417<\/td>\n\u2716 \u6ca1\u6709（\u8001\u5a46 vs \u8001\u5a46\u997c）<\/td>\n<\/tr>\n
                  \u4fe1\u53f7\u91cf\u7684\u672c\u8d28<\/td>\n\u4e00\u4e2a\u8ba1\u6570\u5668，\u662f\u5bf9\u7279\u5b9a\u8d44\u6e90\u7684\u9884\u8ba2\u673a\u5236<\/td>\n<\/tr>\n
                  \u7535\u5f71\u9662\u6bd4\u55bb\u4e70\u7684\u662f\u4ec0\u4e48<\/td>\n\u4e70\u7968 = \u9884\u8ba2；\u7968\u5230\u624b\u5ea7\u4f4d\u5c31\u662f\u4f60\u7684，\u4eba\u4e0d\u53bb\u4e5f\u7559\u7740<\/td>\n<\/tr>\n
                  sem = 1 \u53eb\u4ec0\u4e48<\/td>\n\u4e8c\u5143\u4fe1\u53f7\u91cf，\u672c\u8d28\u5c31\u662f\u4e92\u65a5<\/td>\n<\/tr>\n
                  \u8d44\u6e90\u6574\u4f53\u4f7f\u7528\u7528\u4ec0\u4e48<\/td>\nmutex \u6216\u4e8c\u5143\u4fe1\u53f7\u91cf<\/td>\n<\/tr>\n
                  \u8d44\u6e90\u6309\u5757\u5206\u6279\u4f7f\u7528\u7528\u4ec0\u4e48<\/td>\n\u591a\u5143\u4fe1\u53f7\u91cf<\/td>\n<\/tr>\n
                  \u4e3a\u4ec0\u4e48\u4fe1\u53f7\u91cf\u672c\u8eab\u4e5f\u662f\u4e34\u754c\u8d44\u6e90<\/td>\n\u5b83\u8981\u88ab\u6240\u6709\u7ebf\u7a0b\u770b\u5230\u3001\u8981\u88ab ++\/–，\u800c ++\/– \u4e0d\u662f\u539f\u5b50\u7684<\/td>\n<\/tr>\n
                  P \/ V \u662f\u4ec0\u4e48<\/td>\nP = sem_wait（–，\u7533\u8bf7）\/ V = sem_post（++，\u5f52\u8fd8），\u90fd\u5fc5\u987b\u539f\u5b50<\/td>\n<\/tr>\n
                  \u73af\u5f62\u961f\u5217\u7a7a\u548c\u6ee1\u7684\u9ebb\u70e6<\/td>\nhead == tail \u5206\u4e0d\u51fa\u6765 \u2192 \u52a0 count \u6216\u7a7a\u4e00\u4e2a\u4f4d\u7f6e<\/td>\n<\/tr>\n
                  \u4f46\u4eca\u5929\u8fd8\u9700\u8981\u5224\u65ad\u7a7a\u6ee1\u5417<\/td>\n\u2716 \u4e0d\u9700\u8981，\u4fe1\u53f7\u91cf\u66ff\u4ee3\u4e86\u5224\u65ad<\/td>\n<\/tr>\n
                  \u73af\u5f62\u961f\u5217\u7684\u56db\u6761\u7ea6\u5b9a<\/td>\n\u2460 \u7a7a\u751f\u4ea7\u8005\u5148\u8dd1 \u2461 \u6ee1\u6d88\u8d39\u8005\u5148\u8dd1 \u2462 \u751f\u4ea7\u8005\u4e0d\u80fd\u5957\u6d88\u8d39\u8005\u4e00\u5708\u4ee5\u4e0a \u2463 \u6d88\u8d39\u8005\u4e0d\u80fd\u8d85\u8fc7\u751f\u4ea7\u8005<\/td>\n<\/tr>\n
                  \u4ec0\u4e48\u65f6\u5019\u80fd\u540c\u65f6\u8dd1<\/td>\n\u4e0d\u4e3a\u7a7a && \u4e0d\u4e3a\u6ee1<\/td>\n<\/tr>\n
                  \u4ec0\u4e48\u65f6\u5019\u8981\u540c\u6b65\u4e92\u65a5<\/td>\n\u4e3a\u7a7a || \u4e3a\u6ee1<\/td>\n<\/tr>\n
                  \u751f\u4ea7\u8005\u5173\u5fc3\u4ec0\u4e48\u8d44\u6e90<\/td>\n\u7a7a\u4f4d\u7f6e，sem_blank \u521d\u503c N<\/td>\n<\/tr>\n
                  \u6d88\u8d39\u8005\u5173\u5fc3\u4ec0\u4e48\u8d44\u6e90<\/td>\n\u6570\u636e，sem_data \u521d\u503c 0<\/td>\n<\/tr>\n
                  \u5355\u751f\u4ea7\u5355\u6d88\u8d39\u8981\u52a0\u9501\u5417<\/td>\n\u2716 \u4e0d\u8981，\u4fe1\u53f7\u91cf\u5df2\u7ecf\u591f\u4e86<\/td>\n<\/tr>\n
                  \u591a\u751f\u4ea7\u591a\u6d88\u8d39\u8981\u52a0\u51e0\u628a\u9501<\/td>\n\u4e24\u628a（\u751f\u4ea7\u8005\u4e00\u628a\u3001\u6d88\u8d39\u8005\u4e00\u628a）<\/td>\n<\/tr>\n
                  \u5148\u52a0\u9501\u8fd8\u662f\u5148 P<\/td>\n\u2605 \u5148 P，\u540e\u52a0\u9501（\u5148\u74dc\u5206\u8d44\u6e90\u518d\u6392\u961f）<\/td>\n<\/tr>\n
                  \u4e3a\u4ec0\u4e48\u4fe1\u53f7\u91cf\u4ee3\u7801\u91cc\u6ca1\u6709\u5224\u65ad<\/td>\n\u7533\u8bf7\u5931\u8d25 = \u6761\u4ef6\u4e0d\u6ee1\u8db3，\u5224\u5b9a\u88ab\u539f\u5b50\u5730\u585e\u8fdb\u4e86 P \u91cc<\/td>\n<\/tr>\n
                  \u4fe1\u53f7\u91cf\u628a\u4ec0\u4e48\u63d0\u524d\u4e86<\/td>\n\u628a"\u8d44\u6e90\u662f\u5426\u5b58\u5728"\u7684\u5224\u5b9a，\u4ee5\u539f\u5b50\u5f62\u5f0f\u5448\u73b0\u5728\u8bbf\u95ee\u4e4b\u524d<\/td>\n<\/tr>\n
                  sem_blank \u521d\u503c\u6539\u6210 1 \u4f1a\u600e\u6837<\/td>\n\u9000\u5316\u6210\u4e92\u65a5\u9501（\u73af\u5f62\u961f\u5217\u53ea\u5269\u4e00\u4e2a\u683c\u5b50）<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                  \u5199\u4ee3\u7801\u65f6\u7684\u4e00\u6761\u4e3b\u7ebf<\/h4>\n

                  \u2460 \u8d44\u6e90\u80fd\u6309\u5757\u62c6\u5417？
                  \n \u251c\u2500 \u80fd（\u81ea\u5df1\u63a7\u4e0b\u6807\u3001\u56fa\u5b9a\u5927\u5c0f）\u2192 \u7528\u4fe1\u53f7\u91cf
                  \n \u2502 \u751f\u4ea7\u8005：P(\u7a7a\u4f4d) \u2192 \u751f\u4ea7 \u2192 V(\u6570\u636e)
                  \n \u2502 \u6d88\u8d39\u8005：P(\u6570\u636e) \u2192 \u6d88\u8d39 \u2192 V(\u7a7a\u4f4d)
                  \n \u2514\u2500 \u4e0d\u80fd（\u5bb9\u5668\u6574\u4f53\u3001\u4f1a\u6269\u5bb9） \u2192 \u7528 mutex + \u6761\u4ef6\u53d8\u91cf<\/p>\n

                  \u2461 \u662f\u5355\u751f\u4ea7\u5355\u6d88\u8d39\u5417？
                  \n \u251c\u2500 \u662f \u2192 \u4fe1\u53f7\u91cf\u8db3\u591f，\u4e0d\u7528\u9501
                  \n \u2514\u2500 \u5426 \u2192 \u518d\u8865\u4e24\u628a\u9501，\u7ef4\u62a4"\u751f\u4ea7\u8005\u4e4b\u95f4""\u6d88\u8d39\u8005\u4e4b\u95f4"\u7684\u4e92\u65a5<\/p>\n

                  \u2462 \u52a0\u9501\u548c P \u8c01\u5728\u524d？
                  \n \u2192 \u6c38\u8fdc\u3010\u5148 P \u540e\u52a0\u9501\u3011：\u5148\u9884\u5b9a，\u518d\u6392\u961f<\/p>\n","protected":false},"excerpt":{"rendered":"

                  \u4e00\u3001\u5148\u56de\u987e：\u4fe1\u53f7\u91cf\u5230\u5e95\u662f\u4e2a\u4ec0\u4e48\u4e1c\u897f
                  \n1.1 \u4fe1\u53f7 \u2260 \u4fe1\u53f7\u91cf\u4fe1\u53f7\u548c\u4fe1\u53f7\u91cf，\u662f\u300c\u8001\u5a46\u300d\u548c\u300c\u8001\u5a46\u997c\u300d\u7684\u5173\u7cfb \u2014\u2014 \u6ca1\u6709\u4efb\u4f55\u5173\u7cfb\u3002\u4fe1\u53f7（signal）\u4fe1\u53f7\u91cf（semaphore \/ \u4fe1\u53f7\u706f）\u672c\u8d28\u4e00\u79cd\u8fdb\u7a0b\u95f4\u5f02\u6b65\u901a\u77e5\u7684\u65b9\u5f0f\u4e00\u4e2a\u8ba1\u6570\u5668\u4f5c\u7528\u901a\u77e5\u4f60\\”\u51fa\u4e8b\u4e86\\”\u8868\u660e\u4e34\u754c\u8d44\u6e90\u4e2d\u8d44\u6e90\u6570\u91cf\u8fd8\u5269\u591a\u5c11\u6bd4\u55bb\u95e8\u94c3\u505c\u8f66\u573a\u7684\u4f59\u4f4d\u663e\u793a\u5c4f1.2 POSIX \u4e0e System V
                  \nsem_init \/ sem_wait \/ sem_po<\/p>\n","protected":false},"author":2,"featured_media":116264,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[84],"topic":[],"class_list":["post-116269","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-android"],"yoast_head":"\nPOSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/116269.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"\u4e00\u3001\u5148\u56de\u987e：\u4fe1\u53f7\u91cf\u5230\u5e95\u662f\u4e2a\u4ec0\u4e48\u4e1c\u897f 1.1 \u4fe1\u53f7 \u2260 \u4fe1\u53f7\u91cf\u4fe1\u53f7\u548c\u4fe1\u53f7\u91cf，\u662f\u300c\u8001\u5a46\u300d\u548c\u300c\u8001\u5a46\u997c\u300d\u7684\u5173\u7cfb \u2014\u2014 \u6ca1\u6709\u4efb\u4f55\u5173\u7cfb\u3002\u4fe1\u53f7（signal）\u4fe1\u53f7\u91cf（semaphore \/ \u4fe1\u53f7\u706f）\u672c\u8d28\u4e00\u79cd\u8fdb\u7a0b\u95f4\u5f02\u6b65\u901a\u77e5\u7684\u65b9\u5f0f\u4e00\u4e2a\u8ba1\u6570\u5668\u4f5c\u7528\u901a\u77e5\u4f60"\u51fa\u4e8b\u4e86"\u8868\u660e\u4e34\u754c\u8d44\u6e90\u4e2d\u8d44\u6e90\u6570\u91cf\u8fd8\u5269\u591a\u5c11\u6bd4\u55bb\u95e8\u94c3\u505c\u8f66\u573a\u7684\u4f59\u4f4d\u663e\u793a\u5c4f1.2 POSIX \u4e0e System V sem_init \/ sem_wait \/ sem_po\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/116269.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-10-20T18:24:55+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/10\/20261020182441-6ad7b1e9da2b6.png\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"7 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/116269.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/116269.html\",\"name\":\"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"isPartOf\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\"},\"datePublished\":\"2026-10-20T18:24:55+00:00\",\"dateModified\":\"2026-10-20T18:24:55+00:00\",\"author\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41\"},\"breadcrumb\":{\"@id\":\"https:\/\/www.wsisp.com\/helps\/116269.html#breadcrumb\"},\"inLanguage\":\"zh-Hans\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.wsisp.com\/helps\/116269.html\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/116269.html#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"\u9996\u9875\",\"item\":\"https:\/\/www.wsisp.com\/helps\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#website\",\"url\":\"https:\/\/www.wsisp.com\/helps\/\",\"name\":\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\",\"description\":\"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"zh-Hans\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41\",\"name\":\"admin\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"zh-Hans\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery\",\"contentUrl\":\"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery\",\"caption\":\"admin\"},\"sameAs\":[\"http:\/\/wp.wsisp.com\"],\"url\":\"https:\/\/www.wsisp.com\/helps\/author\/admin\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.wsisp.com\/helps\/116269.html","og_locale":"zh_CN","og_type":"article","og_title":"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","og_description":"\u4e00\u3001\u5148\u56de\u987e：\u4fe1\u53f7\u91cf\u5230\u5e95\u662f\u4e2a\u4ec0\u4e48\u4e1c\u897f 1.1 \u4fe1\u53f7 \u2260 \u4fe1\u53f7\u91cf\u4fe1\u53f7\u548c\u4fe1\u53f7\u91cf，\u662f\u300c\u8001\u5a46\u300d\u548c\u300c\u8001\u5a46\u997c\u300d\u7684\u5173\u7cfb \u2014\u2014 \u6ca1\u6709\u4efb\u4f55\u5173\u7cfb\u3002\u4fe1\u53f7（signal）\u4fe1\u53f7\u91cf（semaphore \/ \u4fe1\u53f7\u706f）\u672c\u8d28\u4e00\u79cd\u8fdb\u7a0b\u95f4\u5f02\u6b65\u901a\u77e5\u7684\u65b9\u5f0f\u4e00\u4e2a\u8ba1\u6570\u5668\u4f5c\u7528\u901a\u77e5\u4f60\"\u51fa\u4e8b\u4e86\"\u8868\u660e\u4e34\u754c\u8d44\u6e90\u4e2d\u8d44\u6e90\u6570\u91cf\u8fd8\u5269\u591a\u5c11\u6bd4\u55bb\u95e8\u94c3\u505c\u8f66\u573a\u7684\u4f59\u4f4d\u663e\u793a\u5c4f1.2 POSIX \u4e0e System V sem_init \/ sem_wait \/ sem_po","og_url":"https:\/\/www.wsisp.com\/helps\/116269.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-10-20T18:24:55+00:00","og_image":[{"url":"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/10\/20261020182441-6ad7b1e9da2b6.png"}],"author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"7 \u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.wsisp.com\/helps\/116269.html","url":"https:\/\/www.wsisp.com\/helps\/116269.html","name":"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","isPartOf":{"@id":"https:\/\/www.wsisp.com\/helps\/#website"},"datePublished":"2026-10-20T18:24:55+00:00","dateModified":"2026-10-20T18:24:55+00:00","author":{"@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41"},"breadcrumb":{"@id":"https:\/\/www.wsisp.com\/helps\/116269.html#breadcrumb"},"inLanguage":"zh-Hans","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.wsisp.com\/helps\/116269.html"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.wsisp.com\/helps\/116269.html#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"\u9996\u9875","item":"https:\/\/www.wsisp.com\/helps"},{"@type":"ListItem","position":2,"name":"POSIX\u4fe1\u53f7\u91cf\u4e0e\u73af\u5f62\u961f\u5217"}]},{"@type":"WebSite","@id":"https:\/\/www.wsisp.com\/helps\/#website","url":"https:\/\/www.wsisp.com\/helps\/","name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","description":"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"zh-Hans"},{"@type":"Person","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41","name":"admin","image":{"@type":"ImageObject","inLanguage":"zh-Hans","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/image\/","url":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","contentUrl":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","caption":"admin"},"sameAs":["http:\/\/wp.wsisp.com"],"url":"https:\/\/www.wsisp.com\/helps\/author\/admin"}]}},"_links":{"self":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/116269","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/comments?post=116269"}],"version-history":[{"count":0,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/116269\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media\/116264"}],"wp:attachment":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media?parent=116269"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/categories?post=116269"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/tags?post=116269"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/topic?post=116269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}