如何使用fork()创建5个进程? [英] How can i create 5 Processes using fork()?

问题描述

我想创建5个进程，就像显示的图片一样，我通过打印出它们的pid尝试了一点点，但是我很难直观地查看创建它们的fork()并得到我想要的[图像显示5个进程通过管道连接]

I want to create 5 processes just like the picture shown i have tried a lil bit by printing out their pid's but its hard for me to visualize the fork() creating them and get exactly what I want [The image shows 5 processes connected by pipes]

          P
       /     \
      M       M
      |        |
      C        C

推荐答案

当您使用 fork()时，内核将创建一个新进程并将其返回给子进程(新过程) 0 和 PID 到父级.因此，知道了这是以下创建树的代码

When you use fork() the kernel will create one new process and will return to the child (the new process) 0 and the PID to the parent. So, knowing this this is the following code to create the tree

if ((pid = fork()) == 0) {
    //I am process M1
    if (pid = form()) == 0) {
       //I am process C1
    } 
} else {
// I am still in P, so go on the next branch
    if ((pid = fork()) == 0) {
       //I am process M2
       if (pid = form()) == 0) {
          //I am process C2
       }
    }
} 

使用 ps --forest 可视化流程树，如以下示例所示

Use ps --forest to visualize the process tree as in following example

~# ps --forest
    PID TTY          TIME CMD
   1295 pts/0    00:00:00 sudo
   1296 pts/0    00:00:00  \_ su
   1297 pts/0    00:00:01      \_ bash
   3541 pts/0    00:00:00          \_ ps

所以您将看到类似的内容:

So you will see something like:

~# ps --forest
    PID TTY          TIME CMD
   1295 pts/0    00:00:00 a.out
   1296 pts/0    00:00:00  \_ a.out
   1297 pts/0    00:00:00      \_ a.out
   1298 pts/0    00:00:00  \_ a.out
   1299 pts/0    00:00:00      \_ a.out

哪位会告诉您您是否成功制作了树.

Which will tell you if you have successfully made the tree.

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