{"id":1798,"date":"2019-01-05T09:51:35","date_gmt":"2019-01-05T01:51:35","guid":{"rendered":"https:\/\/www.yusian.com\/blog\/?p=1798"},"modified":"2020-12-02T10:05:17","modified_gmt":"2020-12-02T02:05:17","slug":"linux%e7%bc%96%e7%a8%8b-%e8%bf%9b%e7%a8%8b%e7%9a%84%e5%9f%ba%e6%9c%ac%e4%bd%bf%e7%94%a8","status":"publish","type":"post","link":"https:\/\/www.yusian.com\/blog\/cpp\/2019\/01\/05\/0951351798.html","title":{"rendered":"Linux\u7f16\u7a0b&#8211;\u8fdb\u7a0b\u7684\u57fa\u672c\u4f7f\u7528"},"content":{"rendered":"<h3>1\u3001\u521b\u5efa\u8fdb\u7a0b\u7684\u51fd\u6570\u4e3afork<\/h3>\n<ul>\n<li>\u5b50\u8fdb\u7a0b\u4f1a\u5728\u5f53\u524d\u8fdb\u7a0b\u7684\u57fa\u7840\u4e0a\u521b\u5efa<\/li>\n<li>\u521b\u5efa\u7684\u5b50\u7a0b\u4e0e\u5f53\u524d\u8fdb\u7a0b\u90fd\u4f1a\u6267\u884c\u8fdb\u7a0b\u540e\u7684\u4ee3\u7801<\/li>\n<\/ul>\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;sys\/types.h&gt;\n#include &lt;unistd.h&gt;\n\nint main(){\n\n    pid_t pid = getpid();\n    printf(\"pid:%u\\n\" ,pid);\n\n    \/\/ \u4ece\u6b64\u5904\u5f00\u59cb\uff0c\u540e\u9762\u7684\u4ee3\u7801\u4f1a\u88ab\u6267\u884c2\u6b21\n    pid_t fork_pid = fork();\n    if (fork_pid == -1){\n        perror(\"fork error:\");\n        exit(1);\n    }else if (fork_pid == 0){\n        \/\/ \u4e3a0\u662f\u8fd4\u56de\u7ed9\u5b50\u7ebf\u7a0b\uff0c\u8868\u660e\u7ebf\u7a0b\u521b\u5efa\u6210\u529f\n        \/\/ \u5f53\u524d\u64cd\u4f5c\u5728\u5b50\u7ebf\u7a0b\u4e2d\u6267\u884c\n        printf(\"\u5b50\u8fdb\u7a0b:pid:%u, ppid:%u\\n\", getpid(), getppid());\n    }else{\n        \/\/ \u7236\u7ebf\u7a0b\u4e2d\u8fd4\u56de\u7684\u662f\u5b50\u7ebf\u7a0bid\u53f7\n        printf(\"\u7236\u8fdb\u7a0b:pid:%u, ppid:%u\\n\", getpid(), getppid());\n    }\n    printf(\"fork:%u\\n\", fork_pid);\n    return 0;\n}\n<\/code><\/pre>\n<p>\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<!--more--><\/p>\n<pre><code class=\"language-cmd line-numbers\">pid:30963\n\u7236\u8fdb\u7a0b:pid:30963, ppid:11330\nfork:30964\n\u5b50\u8fdb\u7a0b:pid:30964, ppid:30963\nfork:0\n<\/code><\/pre>\n<h3>2\u3001\u5faa\u73af\u521b\u5efa\u8fdb\u7a0b<\/h3>\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;unistd.h&gt;\n\nint main(){\n    printf(\"\u7236\u8fdb\u7a0bid\uff1a%u\\n\", getpid());\n    int i;\n    for(i = 0;i &lt; 5; i++){\n        pid_t pid = fork();\n        if (pid == -1){\n            perror(\"fork error:\");\n        }else if(pid == 0){\n            \/\/ \u5b50\u8fdb\u7a0b\u8df3\u51fa\u5faa\u73af\uff0c\u4ee5\u514d\u518d\u6b21\u521b\u5efa\u8fdb\u7a0b\uff0c\u6307\u6570\u7ea7\u589e\u957f\n            printf(\"\u7b2c%d\u4e2a\u5b50\u8fdb\u7a0b\uff0cid\uff1a%u\\n\", i+1, getpid());\n            break;\n        }else{\n            sleep(1);\n        }\n    }\n    return 0;\n}\n<\/code><\/pre>\n<p>\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n<pre><code class=\"language-cmd line-numbers\">\u7236\u8fdb\u7a0bid\uff1a19575\n\u7b2c1\u4e2a\u5b50\u8fdb\u7a0b\uff0cid\uff1a19576\n\u7b2c2\u4e2a\u5b50\u8fdb\u7a0b\uff0cid\uff1a19577\n\u7b2c3\u4e2a\u5b50\u8fdb\u7a0b\uff0cid\uff1a19581\n\u7b2c4\u4e2a\u5b50\u8fdb\u7a0b\uff0cid\uff1a19585\n\u7b2c5\u4e2a\u5b50\u8fdb\u7a0b\uff0cid\uff1a19589\n<\/code><\/pre>\n<h3>3\u3001\u8fdb\u7a0b\u5171\u4eab<\/h3>\n<ul>\n<li>\u4e0d\u540c\u8fdb\u7a0b\u4e4b\u95f4\uff0c\u5185\u5b58\u7a7a\u95f4\u76f8\u4e92\u72ec\u7acb\uff0c\u4e92\u4e0d\u5f71\u54cd<\/li>\n<li>fork\u65f6\uff1a\n<ul>\n<li>\u76f8\u540c\u70b9\uff1a\u5168\u5c40\u53d8\u91cf\u3001\u6570\u636e\u6bb5\u3001\u4ee3\u7801\u6bb5\u3001\u6808\u3001\u5806\u3001\u73af\u5883\u53d8\u91cf\u3001\u7528\u6237ID\u3001\u4e3b\u76ee\u5f55\u3001\u8fdb\u7a0b\u5de5\u4f5c\u76ee\u5f55\u7b49\uff1b<\/li>\n<li>\u4e0d\u540c\u70b9\uff1a\u8fdb\u7a0bid\u3001fork\u8fd4\u56de\u503c\u3001\u7236\u8fdb\u7a0bid\u3001\u8fdb\u7a0b\u8fd0\u884c\u65f6\u95f4\u3001\u95f9\u949f(\u5b9a\u65f6\u5668)\u3001\u672a\u51b3\u4fe1\u53f7\u96c6\u7b49\uff1b<\/li>\n<\/ul>\n<\/li>\n<li>fork\u540e\uff1a\n<ul>\n<li>\u8bfb\u65f6\u5171\u4eab\uff0c\u5199\u65f6\u590d\u5236\u7684\u539f\u5219<\/li>\n<li>\u5148\u6267\u884c\u5b50\u8fdb\u7a0b\u8fd8\u662f\u7236\u8fdb\u7a0b\u662f\u4e0d\u786e\u5b9a\u7684\uff0c\u53d6\u51b3\u4e8e\u5185\u6838\u6240\u4f7f\u7528\u7684\u8c03\u5ea6\u7b97\u6cd5\uff1b<\/li>\n<\/ul>\n<\/li>\n<li>\u5171\u4eab\u6587\u4ef6\u63cf\u8ff0\u7b26<\/li>\n<li>\u5171\u4eabmmap\u5efa\u7acb\u7684\u6620\u5c04\u533a<\/li>\n<\/ul>\n<h3>4\u3001gdb<\/h3>\n<ul>\n<li>set follow-fork-mode\n<ul>\n<li>parent \u2014> \u8ddf\u8e2a\u7236\u8fdb\u7a0b<\/li>\n<li>child \u2014> \u8ddf\u8e2a\u5b50\u8fdb\u7a0b<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>5\u3001exec\u51fd\u6570\u7c07<\/h3>\n<pre><code class=\"language-c line-numbers\">extern char **environ;\n\/\/ \u7b2c\u4e00\u4e2a\u53c2\u6570\u4e3a\u51fd\u6570\u8def\u5f84\uff0c\u63a5\u4e0b\u6765\u7684\u53c2\u6570\u4e3a\u7a0b\u5e8f\u7684\u8f6c\u5165\u53c2\u6570\u4eceargv[0]\u5f00\u59cb\nint execl(const char *path, const char *arg0, ... \/*, (char *)0 *\/);\n\/\/ execle\u4e2d\u7684e\u6307\u7684\u662fenviron\uff0c\u73af\u5883\u53d8\u91cf\u8868\nint execle(const char *path, const char *arg0, ... \/*, (char *)0, char *const envp[] *\/);\n\/\/ \u76f8\u5bf9execl\u51fd\u6570\uff0cexeclp\u52a0\u8f7d\u4e86\u73af\u5883\u53d8\u91cf\u4e2d\u7684PATH\uff0c\u53ef\u901a\u8fc7\u73af\u5883\u53d8\u91cf\u5bfb\u627e\u6267\u884c\u76ee\u6807\nint execlp(const char *file, const char *arg0, ... \/*, (char *)0 *\/);\n\/\/ execv\u4e2d\u7684v\u6307\u7684\u662fargv\uff0c\nint execv(const char *path, char *const argv[]);\n\nint execvp(const char *file, char *const argv[]);\n\nint execvP(const char *file, const char *search_path, char *const argv[]);\n<\/code><\/pre>\n<ul>\n<li>\u8be5\u51fd\u6570\u7684\u4f5c\u7528\u5728\u4e8e\u4f7f\u5b50\u8fdb\u7a0b\u6267\u884c\u6307\u5b9a\u7684\u7a0b\u5e8f\uff0c\u800c\u975e\u6cbf\u7740\u7236\u8fdb\u7a0b\u7ee7\u7eed\u5f80\u4e0b\u91cd\u590d\u6267\u884c\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;unistd.h&gt;\nint main(){\n  \/\/ \u521b\u5efa\u4e00\u4e2a\u5b50\u8fdb\u7a0b\n  pid_t pid = fork();\n  if (pid == -1){\n      perror(\"fork error:\");\n      exit(1);\n  }else if(pid == 0){\n      \/\/ \u5b50\u8fdb\u7a0b\u6267\u884cls\u547d\u4ee4\u4ee5\u53cals\u547d\u4ee4\u9700\u8981\u7684\u8f93\u5165\u5165\u53c2\u6570\n      \/\/execl(\"\/bin\/ls\", \"ls\", \"-l\", \"-a\", NULL);\n      \/\/execlp(\"ls\", \"ls\", \"-l\", \"-a\", NULL);\n      char* argv[] = {\"ls\", \"-l\", \"-a\", NULL};\n      execv(\"\/bin\/ls\", argv);\n  }else{\n      \/\/ \u7236\u8fdb\u7a0b\n      sleep(1);\n      printf(\"pid:%u\\n\", getpid());\n  }\n  return 0;\n}\n<\/code><\/pre>\n<p>\u6267\u884c\u7ed3\u679c\uff1a<\/p>\n<pre><code class=\"language-c line-numbers\">total 24\ndrwxrwxr-x 2 parallels parallels 4096 Jan  6 11:33 .\ndrwxrwxr-x 8 parallels parallels 4096 Jan  6 11:13 ..\n-rwxrwxr-x 1 parallels parallels 8560 Jan  6 11:33 a.out\n-rw-rw-r-- 1 parallels parallels  333 Jan  6 11:33 exec.c\npid:11479\n<\/code><\/pre>\n<\/li>\n<li>fork\u3001exec\u4e0edup2\u7684\u7efc\u5408\u4f7f\u7528\n<ul>\n<li>\u8981\u6c42\u5b9e\u73b0ls\u7ed3\u679c\u8f93\u51fa\u5230\u6587\u4ef6\u4e2d\uff0c\u7ec8\u7aef\u53ef\u76f4\u63a5\u4f7f\u7528ls -l > out.txt\u65b9\u5f0f\u5b8c\u6210<\/li>\n<li>dup2\u662fdupto\u7684\u610f\u601d\uff0c\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u62f7\u8d1d<\/li>\n<li>\u6587\u4ef6\u63cf\u8ff0\u7b26\u8868\u524d\u4e09\u4e2a0\u30011\u30012\u5206\u522b\u8868\u793astdin\u3001stdout\u3001stderr<\/li>\n<li>\u5982\u679c\u9700\u8981\u5c06\u8f93\u51fa\u7ed3\u679c\u8f6c\u79fb\u5230\u6587\u4ef6\uff0c\u53ef\u4ee5\u901a\u8fc7dup2\u5c06stdout\u6307\u5411\u67d0\u4e2a\u7279\u5b9a\u7684fd<\/li>\n<\/ul>\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;unistd.h&gt;\n#include &lt;fcntl.h&gt;\nint main(){\n  pid_t pid = fork();\n  if (pid == -1){\n      perror(\"fork error\");\n      exit(1);\n  }else if(pid &gt; 0){\n      sleep(1);\n  }else{\n      \/\/ \u5b50\u8fdb\u7a0b\n      int fd = open(\"file.txt\", O_CREAT | O_RDWR, 0664);\n      \/\/ \u5c06\u6587\u4ef6\u63cf\u8ff0\u7b26stdout\uff0cdupto fd\uff0c\u5373\u5c06\u539f\u672c\u6253\u5370\u5728\u7ec8\u7aef\u7684\u4fe1\u606f\u5199\u5165fd\n      int ret = dup2(fd, STDOUT_FILENO);\n      if (ret == -1){\n          perror(\"dup2\");\n          exit(1);\n      }\n      \/\/ \u6ce8\u610f\uff1a\u8be5\u51fd\u6570\u5982\u679c\u6ca1\u6709\u51fa\u9519\u5219\u65e0\u8fd4\u56de\u503c\uff0c\u5373\u610f\u5473\u7740\u540e\u7eed\u4ee3\u7801\u4e0d\u4f1a\u6267\u884c\uff01\uff01\uff01\n      execlp(\"ls\", \"ls\", \"-l\", \"-a\", NULL);\n      \/\/ \u5982\u679cexeclp\u6267\u884c\u6210\u529f\uff0c\u4e0d\u4f1a\u6765\u5230\u8fd9\u91cc\n      close(fd);\n  }\n  return 0;\n}\n<\/code><\/pre>\n<\/li>\n<\/ul>\n<h3>6\u3001\u5b64\u72ec\u8fdb\u7a0b<\/h3>\n<ul>\n<li>\u7236\u8fdb\u7a0b\u5148\u4e8e\u5b50\u8fdb\u7a0b\u7ed3\u675f\uff0c\u5b50\u8fdb\u7a0b\u5c06\u5904\u4e8e\u65e0\u4eba\u7ba1\u8f96\u7684\u72b6\u6001\uff0c\u6b64\u65f6\u5b50\u8fdb\u7a0b\u4f1a\u88ab\u7cfb\u7edf\u6536\u5165\u201c\u5b64\u72ec\u9662\u201d\uff0c\u6b64\u540e\u5b50\u8fdb\u7a0b\u7684\u7236\u8fdb\u7a0b\u4e3a\u5b64\u513f\u9662\u8fdb\u7a0b<\/li>\n<\/ul>\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;unistd.h&gt;\n#include &lt;fcntl.h&gt;\nint main(){\n    \/\/ \u521b\u5efa\u4e00\u4e2a\u65b0\u8fdb\u7a0b\n    pid_t pid = fork();\n    if (pid == -1){\n        perror(\"fork error:\");\n        exit(1);\n    }else if (pid == 0){\n        \/\/ \u5b50\u8fdb\u7a0b\n        int i;\n        for (i = 0; i &lt; 5; i++){\n            \/\/ \u7236\u8fdb\u7a0b\u7ed3\u675f\u540e\uff0c\u7236\u8fdb\u7a0b\u9ed8\u8ba4\u4e3ainit\u8fdb\u7a0b\uff0c\u4e00\u822c\u4e3a1\uff0c\u6240\u4ee5\u6709\u5b64\u513f\u8fdb\u7a0b\u90fd\u4f1a\u88ab\u6302\u5728\u6b64\n            printf(\"I am child, pid=%u, ppid=%u\\n\", getpid(), getppid());\n            sleep(1);\n        }\n    }else{\n        \/\/ \u7236\u8fdb\u7a0b\n        sleep(2);\n        printf(\"I am father, pid=%u, I will died\\n\", getpid());\n    }\n\n\n    return 0;\n}\n<\/code><\/pre>\n<p>\u6267\u884c\u7ed3\u679c<\/p>\n<pre><code class=\"language-cmd line-numbers\">I am child, pid=2570, ppid=2569\nI am child, pid=2570, ppid=2569\nI am father, pid=2569, I will died\nI am child, pid=2570, ppid=1\nparallels@ubuntu:~\/Linux\/process$ I am child, pid=2570, ppid=1\nI am child, pid=2570, ppid=1\n<\/code><\/pre>\n<h3>7\u3001\u50f5\u5c38\u8fdb\u7a0b<\/h3>\n<ul>\n<li>\u5b50\u8fdb\u7a0b\u7ed3\u675f\u540e\uff0c\u7236\u8fdb\u7a0b\u6ca1\u6709\u5bf9\u5b50\u8fdb\u7a0b\u8fdb\u884c\u76f8\u5173\u5904\u7406\uff0c\u6b64\u65f6\u5b50\u8fdb\u7a0b\u5373\u4e3a\u50f5\u5c38\u8fdb\u7a0b<\/li>\n<\/ul>\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;unistd.h&gt;\n#include &lt;fcntl.h&gt;\nint main(){\n    pid_t pid = fork();\n    if (pid == -1){\n        perror(\"fork error\");\n        exit(1);\n    }else if (pid == 0){\n        \/\/ \u5b50\u8fdb\u7a0b\n        sleep(2);\n        printf(\"I am child, pid=%u, ppid=%u, I will died...\\n\", getpid(), getppid());\n    }else{\n        \/\/ \u7236\u8fdb\u7a0b\n        int i;\n        for (i = 0; i &lt; 10; i++){\n            printf(\"I am father ,pid=%u\\n\", getpid());\n            sleep(1);\n        }\n    }\n    return 0;\n}\n<\/code><\/pre>\n<p>\u6267\u884c\u7ed3\u679c<\/p>\n<pre><code class=\"language-cmd line-numbers\">I am father ,pid=4429\nI am father ,pid=4429\nI am father ,pid=4429\nI am child, pid=4430, ppid=4429, I will died...\nI am father ,pid=4429\nI am father ,pid=4429\nI am father ,pid=4429\nI am father ,pid=4429\nI am father ,pid=4429\nI am father ,pid=4429\nI am father ,pid=4429\n<\/code><\/pre>\n<p>\u5728\u5b50\u8fdb\u7a0b\u7ed3\u675f\u540e\uff0c\u7236\u8fdb\u7a0b\u7ed3\u675f\u524d\uff0c\u67e5\u770b\u8fdb\u7a0b<\/p>\n<pre><code class=\"language-cmd line-numbers\">parallels@ubuntu:~$ ps -ax | grep a.out\n 4429 pts\/0    S+     0:00 .\/a.out\n 4430 pts\/0    Z+     0:00 [a.out] &lt;defunct&gt;\n 4452 pts\/1    S+     0:00 grep --color=auto a.out\n<\/code><\/pre>\n<h3>8\u3001wait\u51fd\u6570<\/h3>\n<ul>\n<li>pid_t wait(int *wstatus);\n<ul>\n<li>\u963b\u585e\u7b49\u5f85\u5b50\u8fdb\u7a0b<\/li>\n<li>\u56de\u6536\u5b50\u8fdb\u7a0b\u8d44\u6e90<\/li>\n<li>\u83b7\u53d6\u5b50\u8fdb\u7a0b\u7ed3\u675f\u72b6\u6001<\/li>\n<li>WIFEXITED\u2014>WEXITSTATUS( ) \/\/ \u83b7\u53d6\u5b50\u8fdb\u7a0b\u9000\u51fa\u72b6\u6001<\/li>\n<li>WIFSIGNALED \u2014> WTERMSIG( ) \/\/ \u83b7\u53d6\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u4fe1\u53f7\u7f16\u53f7<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;unistd.h&gt;\n#include &lt;fcntl.h&gt;\n#include &lt;sys\/types.h&gt;\n#include &lt;sys\/wait.h&gt;\nint main(){\n    pid_t pid = fork();\n    if (pid == -1){\n        perror(\"fork error\");\n        exit(1);\n    }else if (pid == 0){\n        \/\/ \u5b50\u8fdb\u7a0b\n        sleep(2);\n        printf(\"I am child, pid=%u, ppid=%u, I will died...\\n\", getpid(), getppid());\n    }else{\n        \/\/ \u7236\u8fdb\u7a0b\n        int wstatus;\/\/ \u51fd\u6570\u4f20\u5165\u503c\n        int ret = wait(&amp;wstatus);\n        if (ret == -1){\n            perror(\"wait error\");\n            exit(1);\n        }\n        \/\/ WIFEXITED()\u5224\u65ad\u662f\u5426\u6b63\u5e38\u9000\u51fa\n        if (WIFEXITED(wstatus)){\n            printf(\"exited with %d\\n\", WEXITSTATUS(wstatus));\n        }\n        \/\/ WIFSIGNALED()\u5224\u65ad\u662f\u5426\u4fe1\u53f7\u9000\u51fa(\u5f02\u5e38\u9000\u51fa)\n        if (WIFSIGNALED(wstatus)){\n            printf(\"signaled with %d\\n\", WTERMSIG(wstatus));\n        }\n        \/\/ WIFSTOPPED()\u5224\u65ad\u662f\u5426\u4e2d\u6b62\n        if (WIFSTOPPED(wstatus)){\n            WSTOPSIG(wstatus);\/\/ \u505c\u6b62\u4fe1\u53f7\u503c\n        }\n        \/\/ WIFCONTINUED()\u5224\u65ad\u662f\u5426\u7ee7\u7eed\n        if (WIFCONTINUED(wstatus)){\n\n        }\n        int i;\n        for (i = 0; i &lt; 10; i++){\n            printf(\"I am father ,pid=%u\\n\", getpid());\n            sleep(1);\n        }\n    }\n    return 0;\n}\n<\/code><\/pre>\n<p>\u6b63\u5e38\u9000\u51fa\u7ed3\u679c\uff1a<\/p>\n<pre><code class=\"language-cmd line-numbers\">I am child, pid=9474, ppid=9473, I will died...\nexited with 0\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\nI am father ,pid=9473\n<\/code><\/pre>\n<p>\u5f02\u5e38\u9000\u51fa\u7ed3\u679c\uff1a<\/p>\n<pre><code class=\"language-cmd line-numbers\">signaled with 9\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\nI am father ,pid=10031\n<\/code><\/pre>\n<h3>9\u3001pid_t waitpid(pid_t pid, int wstatus, int option)<\/h3>\n<ul>\n<li>pid > 0   \u2014>   \u6307\u5b9a\u8fdb\u7a0bid\u56de\u6536<\/li>\n<li>pid = -1  \u2014>  \u56de\u6536\u4efb\u610f\u5b50\u8fdb\u7a0b\uff0c\u7b49\u540c\u4e8ewait( )<\/li>\n<li>pid = 0   \u2014>  \u56de\u6536\u672c\u7ec4\u4efb\u610f\u5b50\u8fdb\u7a0b\uff0c\u9ed8\u8ba4\u7236\u5b50\u8fdb\u7a0b\u540c\u7ec4<\/li>\n<li>pid &lt; -1  \u2014>  \u56de\u6536\u8be5\u8fdb\u7a0b\u7684\u4efb\u610f\u5b50\u8fdb\u7a0b<\/li>\n<li>option = 0  &#8211;>  \u963b\u585e\u56de\u6536<\/li>\n<li>option = WNOHANG  \u2014>  \u975e\u963b\u585e\u56de\u6536<\/li>\n<li>\u8fd4\u56de\u503c\n<ul>\n<li>\u6210\u529f\uff1apid<\/li>\n<li>\u5931\u8d25\uff1a-1<\/li>\n<li>option=WNOHANG\u5e76\u4e14\u5b50\u8fdb\u7a0b\u5c1a\u672a\u7ed3\u675f\uff0c\u8fd4\u56de0<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre><code class=\"language-c line-numbers\">#include &lt;stdio.h&gt;\n#include &lt;stdlib.h&gt;\n#include &lt;unistd.h&gt;\n#include &lt;sys\/wait.h&gt;\n#include &lt;sys\/types.h&gt;\nint main(){\n    int i;\n    pid_t pid;\n    for(i = 0; i &lt; 5; i++){\n        pid = fork();\n        if (pid == -1){\n            perror(\"fork error:\");\n            exit(1);\n        }else if (pid == 0){\n            \/\/ \u7b2c1\u4e2a\u5b50\u8fdb\u7a0b\u6bd4\u7236\u8fdb\u7a0b\u61623\u79d2\uff0c\u540e\u7eed\u6bcf\u4e2a\u5b50\u8fdb\u7a0b\u90fd\u6bd4\u524d\u4e00\u4e2a\u61621\u79d2\n            sleep(i+3);\n            break;\n        }\n    }\n    if (i &lt; 5){\n        \/\/ \u5b50\u8fdb\u7a0b\n        printf(\"I am child pid = %u\\n\", getpid());\n    }else{\n        \/\/ \u7236\u8fdb\u7a0b\n        printf(\"I am father pid = %u\\n\", getpid());\n        \/\/ waitpid(-1, NULL, 0)\u76f8\u5f53\u4e8ewait(NULL)\n        \/\/ \u7b2c\u4e00\u4e2a\u53c2\u6570\u4e3apid\uff0c-1\uff1a\u56de\u6536\u4efb\u610f\u5b50\u7ebf\u7a0b\u3001&gt;0\uff1a\u56de\u6536\u6307\u5b9a\u7ebf\u7a0b\n        \/\/ \u7b2c\u4e09\u4e2a\u53c2\u6570\u8bbe\u4e3aWNOHANG\u5219\u4e3a\u975e\u963b\u585e\u7acb\u5373\u6267\u884c\uff0c\u5982\u679c\u6ca1\u6709\u5b50\u7ebf\u7a0b\u6216\u5b50\u7ebf\u7a0b\u6b63\u5728\u8fd0\u884c\u8fd4\u56de0\n        \/\/ \u5faa\u73af\u6267\u884cwaitpid(-1, NULL, 0)\uff1b\u5219\u4f1a\u5faa\u73af\u53d6\u5b50\u7ebf\u7a0b\n        pid_t pid = waitpid(-1, NULL, 0);\n        printf(\"%d\\n\", pid);\n        \/\/wait(NULL);\n    }\n    return 0;\n}\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>1\u3001\u521b\u5efa\u8fdb\u7a0b\u7684\u51fd\u6570\u4e3afork \u5b50\u8fdb\u7a0b\u4f1a\u5728\u5f53\u524d\u8fdb\u7a0b\u7684\u57fa\u7840\u4e0a\u521b\u5efa \u521b\u5efa\u7684\u5b50\u7a0b\u4e0e\u5f53\u524d\u8fdb\u7a0b\u90fd\u4f1a\u6267\u884c\u8fdb\u7a0b\u540e\u7684\u4ee3\u7801 #include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #include &lt;sys\/types.h&gt; #include &lt;unistd.h&gt; int main(){ pid_t pid = getpid(); printf(&#8220;pid:%u\\n&#8221; ,pid); \/\/ \u4ece\u6b64\u5904\u5f00\u59cb\uff0c\u540e\u9762\u7684\u4ee3\u7801\u4f1a\u88ab\u6267\u884c2\u6b21 pid_t fork_pid = fork(); if (fork_pid == -1){ perror(&#8220;fork error:&#8221;); exit(1); }else if (fork_pid == 0){ \/\/ \u4e3a0\u662f\u8fd4\u56de\u7ed9\u5b50\u7ebf\u7a0b\uff0c\u8868\u660e\u7ebf\u7a0b\u521b\u5efa\u6210\u529f \/\/ \u5f53\u524d\u64cd\u4f5c\u5728\u5b50\u7ebf\u7a0b\u4e2d\u6267\u884c printf(&#8220;\u5b50\u8fdb\u7a0b:pid:%u, ppid:%u\\n&#8221;, getpid(), getppid()); }else{ \/\/ \u7236\u7ebf\u7a0b\u4e2d\u8fd4\u56de\u7684\u662f\u5b50\u7ebf\u7a0bid\u53f7 printf(&#8220;\u7236\u8fdb\u7a0b:pid:%u, ppid:%u\\n&#8221;, getpid(), getppid()); } printf(&#8220;fork:%u\\n&#8221;, fork_pid); [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[88],"tags":[310,313],"class_list":["post-1798","post","type-post","status-publish","format-standard","hentry","category-cpp","tag-linux","tag-313"],"_links":{"self":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/posts\/1798","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/comments?post=1798"}],"version-history":[{"count":0,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/posts\/1798\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/media?parent=1798"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/categories?post=1798"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/tags?post=1798"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}