当进程（父进程和子进程）在同一代码上工作时，使用fork（）系统调用有什么意义？

Question

I read that the parent and the child will work on the identical code after the fork() system call. I cannot understand the point of doing a fork() as I cannot understand what good will it do in executing the same code twice.

Answer 1

The return value of fork() is different in the child and parent processes, so you'll typically have something along the lines of

pid_t child_pid = fork()
if (child_pid == 0) {
  // do stuff in child process
} else {
  // do stuff in parent process
}

Answer 2

You can use an if else condition to execute different piece of code for parent and child. As fork returns 0 to the child process and it returns pid of the child to the parent. Use this as the differentator in the if condition.