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我在 c 中有这个小程序，我试图了解它是如何工作的，它是一个简单的 while 循环，它使用fork()并wait()在命令行上打印出几行，我已经尽我所能评论了我的想法正在发生

for (i = 1; i <= 3; i++)            /*simple while loop, loops 3 times */
{
    pid = fork();                   /*returns 0 if a child process is created */
    if(pid == 0){                   /*pid should be a 0 for first loop */
        printf("Hello!\n");         /*we print hello */
        return (i);                 /*will this return i to the parent process that called fork? */ 
    }   else {                      /*fork hasn't returned 0? */
        pid = wait(&j);             /*we wait until j is available? */
        printf("Received %d\n", WEXITSTATUS(j));   /*if available we print "received (j)" */
    }
}

该程序应该打印：

Hello!
Received 1
Hello!
Received 2
Hello!
Received 3

当其中一个子进程返回时i，父进程是否等待它&j？这真的让我很困惑，任何帮助将不胜感激。

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1 回答 1

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在循环的每次迭代中fork()创建一个子进程。子进程打印Hello!并返回i系统。父进程阻塞，wait()直到子进程完成执行。 j将包含子进程返回给系统的值。

于 2015-08-15T11:12:08.787 回答