在Fork（）之后，如何留在父进程中？

I have an example here:

我在这里有一个例子:

int runcmd(char *cmd)
{
  char* argv[MAX_ARGS];
  pid_t child_pid;
  int child_status;

  parsecmd(cmd,argv);
  child_pid = fork();
  if(child_pid == 0) {
    /* This is done by the child process. */

    execvp(argv[0], argv);

    /* If execvp returns, it must have failed. */

    printf("Unknown command\n");
    exit(0);
  }
  else {
     /* This is run by the parent.  Wait for the child
        to terminate. */

     do {
       pid_t tpid = wait(&child_status);
       if(tpid != child_pid) process_terminated(tpid);
     } while(tpid != child_pid);

     return child_status;
  }
}

This one is a classic example of fork() After fork(), the control goes to child process. How can I keep in parent process, do stuffs. Instead of jumping to child immediately?

这是fork()的经典示例在fork()之后,控件转到子进程。如何保持父进程,做东西。而不是立即跳孩子?

Thank you

3 个解决方案

#1

The child will always be the child. The parent will always be the parent. fork() creates a new process, and each runs separately. If you want to do something in the parent then do it in the parent.

孩子永远是孩子。父母将永远是父母。 fork()创建一个新进程,每个进程单独运行。如果您想在父级中执行某些操作,请在父级中执行此操作。

#2

Once you call fork, the scheduler decides whether the parent or child get to run first. They may even run in parallel: multiple CPUs and cores are common nowadays.

调用fork后,调度程序将决定父项或子项是否先运行。它们甚至可以并行运行:现在多个CPU和核心很常见。

If there is some action that the parent has to take before the child runs, then you should place that action before the fork. Otherwise the parent and child have to synchronize somehow.

如果在子进程运行之前父进程必须执行某些操作,则应将该操作放在fork之前。否则父母和孩子必须以某种方式同步。

#3

When fork() is executed, two separate OS processes are created. So the OS scheduler will then decide when each gets run, you cannot decide that.

执行fork()时,会创建两个单独的OS进程。因此OS调度程序将决定每个运行时间,您无法做出决定。

#1