fork() 4 children 循环

Question

目标是尝试在一个循环中分叉 4 children，但我不确定如何正确地做到这一点。这是我到目前为止所拥有的。我试着把它画出来，我想我已经等不及要好好收割 child 了。我每次迭代都会创建 2 children。所以一共8children.

void main() {
  int i = 0;
  pid_t pid;
  int status;

  for(i = 0; i < 4; i++) {
    pid = fork();
    if(pid == 0) {
      /* Child Process */
      fork();
      exit(0); 
    } else {
      /* Parent Process */
      wait(&status);
      printf("At i = %d, process %d is terminated.\n", i, pid);
    }
  }
}

Answer 1

从同一个 parent 进程创建四个 children 进程可以通过 forking 在 for 循环的每次迭代中实现一次：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main() {
   for (int i = 0; i < 4; i++) {
      pid_t pid = fork();

      if (pid == 0)
         exit(0); // child process

      // parent process
      wait(NULL);
      printf("At i = %d, process %d is terminated.\n", i, pid);
   }
}

但是，您可能希望 parent 进程在创建所有四个 children 之后等待 children ，因为您通常希望 children 在退出之前做一些事情并与另一个 children:

int main() { // create the four children processes for (int i = 0; i < 4; i++) { pid_t pid = fork(); if (pid == 0) { // child process // ... do some stuff ... exit(0); } } // wait for the four children processes to finish for (int i = 0; i < 4; i++) { pid_t pid = wait(NULL); printf("Process %d is terminated.\n", pid); } }

fork() 4 children 循环

fork() 4 children in a loop

c

linux

fork