“`\u53c2\u8003\u56de\u7b54\uff1a<\/p>\n
fork\u7684\u57fa\u7840\u77e5\u8bc6\uff1a<\/p>\n
fork:\u521b\u5efa\u4e00\u4e2a\u548c\u5f53\u524d\u8fdb\u7a0b\u6620\u50cf\u4e00\u6837\u7684\u8fdb\u7a0b\u53ef\u4ee5\u901a\u8fc7fork( )\u7cfb\u7edf\u8c03\u7528\uff1a<\/p>\n
#include <sys\/types.h><\/p>\n
#include <unistd.h><\/p>\n
pid_t fork(void);<\/p>\n
\u6210\u529f\u8c03\u7528fork( )\u4f1a\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u8fdb\u7a0b\uff0c\u5b83\u51e0\u4e4e\u4e0e\u8c03\u7528fork( )\u7684\u8fdb\u7a0b\u4e00\u6a21\u4e00\u6837\uff0c\u8fd9\u4e24\u4e2a\u8fdb\u7a0b\u90fd\u4f1a\u7ee7\u7eed\u8fd0\u884c\u3002\u5728\u5b50\u8fdb\u7a0b\u4e2d\uff0c\u6210\u529f\u7684fork( )\u8c03\u7528\u4f1a\u8fd4\u56de0\u3002\u5728\u7236\u8fdb\u7a0b\u4e2dfork( )\u8fd4\u56de\u5b50\u8fdb\u7a0b\u7684pid\u3002\u5982\u679c\u51fa\u73b0\u9519\u8bef\uff0cfork( )\u8fd4\u56de\u4e00\u4e2a\u8d1f\u503c\u3002<\/p>\n
\u6700\u5e38\u89c1\u7684fork( )\u7528\u6cd5\u662f\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u8fdb\u7a0b\uff0c\u7136\u540e\u4f7f\u7528exec( )\u8f7d\u5165\u4e8c\u8fdb\u5236\u6620\u50cf\uff0c\u66ff\u6362\u5f53\u524d\u8fdb\u7a0b\u7684\u6620\u50cf\u3002\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u6d3e\u751f\uff08fork\uff09\u4e86\u65b0\u7684\u8fdb\u7a0b\uff0c\u800c\u8fd9\u4e2a\u5b50\u8fdb\u7a0b\u4f1a\u6267\u884c\u4e00\u4e2a\u65b0\u7684\u4e8c\u8fdb\u5236\u53ef\u6267\u884c\u6587\u4ef6\u7684\u6620\u50cf\u3002\u8fd9\u79cd\u201c\u6d3e\u751f\u52a0\u6267\u884c\u201d\u7684\u65b9\u5f0f\u662f\u5f88\u5e38\u89c1\u7684\u3002<\/p>\n
\u5728\u65e9\u671f\u7684Unix\u7cfb\u7edf\u4e2d\uff0c\u521b\u5efa\u8fdb\u7a0b\u6bd4\u8f83\u539f\u59cb\u3002\u5f53\u8c03\u7528fork\u65f6\uff0c\u5185\u6838\u4f1a\u628a\u6240\u6709\u7684\u5185\u90e8\u6570\u636e\u7ed3\u6784\u590d\u5236\u4e00\u4efd\uff0c\u590d\u5236\u8fdb\u7a0b\u7684\u9875\u8868\u9879\uff0c\u7136\u540e\u628a\u7236\u8fdb\u7a0b\u7684\u5730\u5740\u7a7a\u95f4\u4e2d\u7684\u5185\u5bb9\u9010\u9875\u7684\u590d\u5236\u5230\u5b50\u8fdb\u7a0b\u7684\u5730\u5740\u7a7a\u95f4\u4e2d\u3002\u4f46\u4ece\u5185\u6838\u89d2\u5ea6\u6765\u8bf4\uff0c\u9010\u9875\u7684\u590d\u5236\u65b9\u5f0f\u662f\u5341\u5206\u8017\u65f6\u7684\u3002\u73b0\u4ee3\u7684Unix\u7cfb\u7edf\u91c7\u53d6\u4e86\u66f4\u591a\u7684\u4f18\u5316\uff0c\u4f8b\u5982Linux\uff0c\u91c7\u7528\u4e86\u5199\u65f6\u590d\u5236\u7684\u65b9\u6cd5\uff0c\u800c\u4e0d\u662f\u5bf9\u7236\u8fdb\u7a0b\u7a7a\u95f4\u8fdb\u7a0b\u6574\u4f53\u590d\u5236\u3002<\/p>\n
\u00a0<\/p>\n
vfork\u7684\u57fa\u7840\u77e5\u8bc6\uff1a<\/p>\n
\u5728\u5b9e\u73b0\u5199\u65f6\u590d\u5236\u4e4b\u524d\uff0cUnix\u7684\u8bbe\u8ba1\u8005\u4eec\u5c31\u4e00\u76f4\u5f88\u5173\u6ce8\u5728fork\u540e\u7acb\u523b\u6267\u884cexec\u6240\u9020\u6210\u7684\u5730\u5740\u7a7a\u95f4\u7684\u6d6a\u8d39\u3002BSD\u7684\u5f00\u53d1\u8005\u4eec\u57283.0\u7684BSD\u7cfb\u7edf\u4e2d\u5f15\u5165\u4e86vfork( )\u7cfb\u7edf\u8c03\u7528\u3002<\/p>\n
#include <sys\/types.h><\/p>\n
#include <unistd.h><\/p>\n
pid_t vfork(void);<\/p>\n
\u9664\u4e86\u5b50\u8fdb\u7a0b\u5fc5\u987b\u8981\u7acb\u523b\u6267\u884c\u4e00\u6b21\u5bf9exec\u7684\u7cfb\u7edf\u8c03\u7528\uff0c\u6216\u8005\u8c03\u7528_exit( )\u9000\u51fa\uff0c\u5bf9vfork( )\u7684\u6210\u529f\u8c03\u7528\u6240\u4ea7\u751f\u7684\u7ed3\u679c\u548cfork( )\u662f\u4e00\u6837\u7684\u3002vfork( )\u4f1a\u6302\u8d77\u7236\u8fdb\u7a0b\u76f4\u5230\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u6216\u8005\u8fd0\u884c\u4e86\u4e00\u4e2a\u65b0\u7684\u53ef\u6267\u884c\u6587\u4ef6\u7684\u6620\u50cf\u3002\u901a\u8fc7\u8fd9\u6837\u7684\u65b9\u5f0f\uff0cvfork( )\u907f\u514d\u4e86\u5730\u5740\u7a7a\u95f4\u7684\u6309\u9875\u590d\u5236\u3002\u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u7236\u8fdb\u7a0b\u548c\u5b50\u8fdb\u7a0b\u5171\u4eab\u76f8\u540c\u7684\u5730\u5740\u7a7a\u95f4\u548c\u9875\u8868\u9879\u3002\u5b9e\u9645\u4e0avfork( )\u53ea\u5b8c\u6210\u4e86\u4e00\u4ef6\u4e8b\uff1a\u590d\u5236\u5185\u90e8\u7684\u5185\u6838\u6570\u636e\u7ed3\u6784\u3002\u56e0\u6b64\uff0c\u5b50\u8fdb\u7a0b\u4e5f\u5c31\u4e0d\u80fd\u4fee\u6539\u5730\u5740\u7a7a\u95f4\u4e2d\u7684\u4efb\u4f55\u5185\u5b58\u3002<\/p>\n
vfork( )\u662f\u4e00\u4e2a\u5386\u53f2\u9057\u7559\u4ea7\u7269\uff0cLinux\u672c\u4e0d\u5e94\u8be5\u5b9e\u73b0\u5b83\u3002\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5373\u4f7f\u589e\u52a0\u4e86\u5199\u65f6\u590d\u5236\uff0cvfork( )\u4e5f\u8981\u6bd4fork( )\u5feb\uff0c\u56e0\u4e3a\u5b83\u6ca1\u6709\u8fdb\u884c\u9875\u8868\u9879\u7684\u590d\u5236\u3002\u7136\u800c\uff0c\u5199\u65f6\u590d\u5236\u7684\u51fa\u73b0\u51cf\u5c11\u4e86\u5bf9\u4e8e\u66ff\u6362fork( )\u4e89\u8bba\u3002\u5b9e\u9645\u4e0a\uff0c\u76f4\u52302.2.0\u5185\u6838\uff0cvfork( )\u53ea\u662f\u4e00\u4e2a\u5c01\u88c5\u8fc7\u7684fork( )\u3002\u56e0\u4e3a\u5bf9vfork( )\u7684\u9700\u6c42\u8981\u5c0f\u4e8efork( )\uff0c\u6240\u4ee5vfork( )\u7684\u8fd9\u79cd\u5b9e\u73b0\u65b9\u5f0f\u662f\u53ef\u884c\u7684\u3002<\/p>\n
\u00a0<\/p>\n
\u8865\u5145\u77e5\u8bc6\u70b9\uff1a\u5199\u65f6\u590d\u5236<\/p>\n
Linux\u91c7\u7528\u4e86\u5199\u65f6\u590d\u5236\u7684\u65b9\u6cd5\uff0c\u4ee5\u51cf\u5c11fork\u65f6\u5bf9\u7236\u8fdb\u7a0b\u7a7a\u95f4\u8fdb\u7a0b\u6574\u4f53\u590d\u5236\u5e26\u6765\u7684\u5f00\u9500\u3002<\/p>\n
\u5199\u65f6\u590d\u5236\u662f\u4e00\u79cd\u91c7\u53d6\u4e86\u60f0\u6027\u4f18\u5316\u65b9\u6cd5\u6765\u907f\u514d\u590d\u5236\u65f6\u7684\u7cfb\u7edf\u5f00\u9500\u3002\u5b83\u7684\u524d\u63d0\u5f88\u7b80\u5355\uff1a\u5982\u679c\u6709\u591a\u4e2a\u8fdb\u7a0b\u8981\u8bfb\u53d6\u5b83\u4eec\u81ea\u5df1\u7684\u90a3\u90e8\u95e8\u8d44\u6e90\u7684\u526f\u672c\uff0c\u90a3\u4e48\u590d\u5236\u662f\u4e0d\u5fc5\u8981\u7684\u3002\u6bcf\u4e2a\u8fdb\u7a0b\u53ea\u8981\u4fdd\u5b58\u4e00\u4e2a\u6307\u5411\u8fd9\u4e2a\u8d44\u6e90\u7684\u6307\u9488\u5c31\u53ef\u4ee5\u4e86\u3002\u53ea\u8981\u6ca1\u6709\u8fdb\u7a0b\u8981\u53bb\u4fee\u6539\u81ea\u5df1\u7684\u201c\u526f\u672c\u201d\uff0c\u5c31\u5b58\u5728\u7740\u8fd9\u6837\u7684\u5e7b\u89c9\uff1a\u6bcf\u4e2a\u8fdb\u7a0b\u597d\u50cf\u72ec\u5360\u90a3\u4e2a\u8d44\u6e90\u3002\u4ece\u800c\u5c31\u907f\u514d\u4e86\u590d\u5236\u5e26\u6765\u7684\u8d1f\u62c5\u3002\u5982\u679c\u4e00\u4e2a\u8fdb\u7a0b\u8981\u4fee\u6539\u81ea\u5df1\u7684\u90a3\u4efd\u8d44\u6e90\u201c\u526f\u672c\u201d\uff0c\u90a3\u4e48\u5c31\u4f1a\u590d\u5236\u90a3\u4efd\u8d44\u6e90\uff0c\u5e76\u628a\u590d\u5236\u7684\u90a3\u4efd\u63d0\u4f9b\u7ed9\u8fdb\u7a0b\u3002\u4e0d\u8fc7\u5176\u4e2d\u7684\u590d\u5236\u5bf9\u8fdb\u7a0b\u6765\u8bf4\u662f\u900f\u660e\u7684\u3002\u8fd9\u4e2a\u8fdb\u7a0b\u5c31\u53ef\u4ee5\u4fee\u6539\u590d\u5236\u540e\u7684\u8d44\u6e90\u4e86\uff0c\u540c\u65f6\u5176\u4ed6\u7684\u8fdb\u7a0b\u4ecd\u7136\u5171\u4eab\u90a3\u4efd\u6ca1\u6709\u4fee\u6539\u8fc7\u7684\u8d44\u6e90\u3002\u6240\u4ee5\u8fd9\u5c31\u662f\u540d\u79f0\u7684\u7531\u6765\uff1a\u5728\u5199\u5165\u65f6\u8fdb\u884c\u590d\u5236\u3002<\/p>\n
\u5199\u65f6\u590d\u5236\u7684\u4e3b\u8981\u597d\u5904\u5728\u4e8e\uff1a\u5982\u679c\u8fdb\u7a0b\u4ece\u6765\u5c31\u4e0d\u9700\u8981\u4fee\u6539\u8d44\u6e90\uff0c\u5219\u4e0d\u9700\u8981\u8fdb\u884c\u590d\u5236\u3002\u60f0\u6027\u7b97\u6cd5\u7684\u597d\u5904\u5c31\u5728\u4e8e\u5b83\u4eec\u5c3d\u91cf\u63a8\u8fdf\u4ee3\u4ef7\u9ad8\u6602\u7684\u64cd\u4f5c\uff0c\u76f4\u5230\u5fc5\u8981\u7684\u65f6\u523b\u624d\u4f1a\u53bb\u6267\u884c\u3002<\/p>\n
\u5728\u4f7f\u7528\u865a\u62df\u5185\u5b58\u7684\u60c5\u51b5\u4e0b\uff0c\u5199\u65f6\u590d\u5236\uff08Copy-On-Write\uff09\u662f\u4ee5\u9875\u4e3a\u57fa\u7840\u8fdb\u884c\u7684\u3002\u6240\u4ee5\uff0c\u53ea\u8981\u8fdb\u7a0b\u4e0d\u4fee\u6539\u5b83\u5168\u90e8\u7684\u5730\u5740\u7a7a\u95f4\uff0c\u90a3\u4e48\u5c31\u4e0d\u5fc5\u590d\u5236\u6574\u4e2a\u5730\u5740\u7a7a\u95f4\u3002\u5728fork( )\u8c03\u7528\u7ed3\u675f\u540e\uff0c\u7236\u8fdb\u7a0b\u548c\u5b50\u8fdb\u7a0b\u90fd\u76f8\u4fe1\u5b83\u4eec\u6709\u4e00\u4e2a\u81ea\u5df1\u7684\u5730\u5740\u7a7a\u95f4\uff0c\u4f46\u5b9e\u9645\u4e0a\u5b83\u4eec\u5171\u4eab\u7236\u8fdb\u7a0b\u7684\u539f\u59cb\u9875\uff0c\u63a5\u4e0b\u6765\u8fd9\u4e9b\u9875\u53c8\u53ef\u4ee5\u88ab\u5176\u4ed6\u7684\u7236\u8fdb\u7a0b\u6216\u5b50\u8fdb\u7a0b\u5171\u4eab\u3002<\/p>\n
\u5199\u65f6\u590d\u5236\u5728\u5185\u6838\u4e2d\u7684\u5b9e\u73b0\u975e\u5e38\u7b80\u5355\u3002\u4e0e\u5185\u6838\u9875\u76f8\u5173\u7684\u6570\u636e\u7ed3\u6784\u53ef\u4ee5\u88ab\u6807\u8bb0\u4e3a\u53ea\u8bfb\u548c\u5199\u65f6\u590d\u5236\u3002\u5982\u679c\u6709\u8fdb\u7a0b\u8bd5\u56fe\u4fee\u6539\u4e00\u4e2a\u9875\uff0c\u5c31\u4f1a\u4ea7\u751f\u4e00\u4e2a\u7f3a\u9875\u4e2d\u65ad\u3002\u5185\u6838\u5904\u7406\u7f3a\u9875\u4e2d\u65ad\u7684\u65b9\u5f0f\u5c31\u662f\u5bf9\u8be5\u9875\u8fdb\u884c\u4e00\u6b21\u900f\u660e\u590d\u5236\u3002\u8fd9\u65f6\u4f1a\u6e05\u9664\u9875\u9762\u7684COW\u5c5e\u6027\uff0c\u8868\u793a\u7740\u5b83\u4e0d\u518d\u88ab\u5171\u4eab\u3002<\/p>\n
\u73b0\u4ee3\u7684\u8ba1\u7b97\u673a\u7cfb\u7edf\u7ed3\u6784\u4e2d\u90fd\u5728\u5185\u5b58\u7ba1\u7406\u5355\u5143\uff08MMU\uff09\u63d0\u4f9b\u4e86\u786c\u4ef6\u7ea7\u522b\u7684\u5199\u65f6\u590d\u5236\u652f\u6301\uff0c\u6240\u4ee5\u5b9e\u73b0\u662f\u5f88\u5bb9\u6613\u7684\u3002<\/p>\n
\u5728\u8c03\u7528fork( )\u65f6\uff0c\u5199\u65f6\u590d\u5236\u662f\u6709\u5f88\u5927\u4f18\u52bf\u7684\u3002\u56e0\u4e3a\u5927\u91cf\u7684fork\u4e4b\u540e\u90fd\u4f1a\u8ddf\u7740\u6267\u884cexec\uff0c\u90a3\u4e48\u590d\u5236\u6574\u4e2a\u7236\u8fdb\u7a0b\u5730\u5740\u7a7a\u95f4\u4e2d\u7684\u5185\u5bb9\u5230\u5b50\u8fdb\u7a0b\u7684\u5730\u5740\u7a7a\u95f4\u5b8c\u5168\u662f\u5728\u6d6a\u8d39\u65f6\u95f4\uff1a\u5982\u679c\u5b50\u8fdb\u7a0b\u7acb\u523b\u6267\u884c\u4e00\u4e2a\u65b0\u7684\u4e8c\u8fdb\u5236\u53ef\u6267\u884c\u6587\u4ef6\u7684\u6620\u50cf\uff0c\u5b83\u5148\u524d\u7684\u5730\u5740\u7a7a\u95f4\u5c31\u4f1a\u88ab\u4ea4\u6362\u51fa\u53bb\u3002\u5199\u65f6\u590d\u5236\u53ef\u4ee5\u5bf9\u8fd9\u79cd\u60c5\u51b5\u8fdb\u884c\u4f18\u5316\u3002<\/p>\n
\u00a0<\/p>\n
fork\u548cvfork\u7684\u533a\u522b\uff1a<\/p>\n
\\1. fork( )\u7684\u5b50\u8fdb\u7a0b\u62f7\u8d1d\u7236\u8fdb\u7a0b\u7684\u6570\u636e\u6bb5\u548c\u4ee3\u7801\u6bb5\uff1bvfork( )\u7684\u5b50\u8fdb\u7a0b\u4e0e\u7236\u8fdb\u7a0b\u5171\u4eab\u6570\u636e\u6bb5<\/p>\n
\\2. fork( )\u7684\u7236\u5b50\u8fdb\u7a0b\u7684\u6267\u884c\u6b21\u5e8f\u4e0d\u786e\u5b9a\uff1bvfork( )\u4fdd\u8bc1\u5b50\u8fdb\u7a0b\u5148\u8fd0\u884c\uff0c\u5728\u8c03\u7528exec\u6216exit\u4e4b\u524d\u4e0e\u7236\u8fdb\u7a0b\u6570\u636e\u662f\u5171\u4eab\u7684\uff0c\u5728\u5b83\u8c03\u7528exec\u6216exit\u4e4b\u540e\u7236\u8fdb\u7a0b\u624d\u53ef\u80fd\u88ab\u8c03\u5ea6\u8fd0\u884c\u3002<\/p>\n
\\3. vfork( )\u4fdd\u8bc1\u5b50\u8fdb\u7a0b\u5148\u8fd0\u884c\uff0c\u5728\u5b83\u8c03\u7528exec\u6216exit\u4e4b\u540e\u7236\u8fdb\u7a0b\u624d\u53ef\u80fd\u88ab\u8c03\u5ea6\u8fd0\u884c\u3002\u5982\u679c\u5728\u8c03\u7528\u8fd9\u4e24\u4e2a\u51fd\u6570\u4e4b\u524d\u5b50\u8fdb\u7a0b\u4f9d\u8d56\u4e8e\u7236\u8fdb\u7a0b\u7684\u8fdb\u4e00\u6b65\u52a8\u4f5c\uff0c\u5219\u4f1a\u5bfc\u81f4\u6b7b\u9501\u3002<\/p>\n
4.\u5f53\u9700\u8981\u6539\u53d8\u5171\u4eab\u6570\u636e\u6bb5\u4e2d\u53d8\u91cf\u7684\u503c\uff0c\u5219\u62f7\u8d1d\u7236\u8fdb\u7a0b\u3002<\/p>\n
“`<\/p>\n","protected":false},"excerpt":{"rendered":"
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