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我的子进程无法使用 Pipe 从父进程接收最后一个值

[英]My child process cannot receive the last value from parent process using Pipe

原文 2017-01-14 22:40:15 2 1 c/ multithreading/ pipe/ fork

in my program, child process should receive some value from keyboard, and send to parent process.在我的程序中，子进程应该从键盘接收一些值，然后发送给父进程。 Parent process should calculate the sum and return to child process.父进程应该计算总和并返回到子进程。 My program is shown below:我的程序如下所示：

3 4 5 -1 child(4753): Sending 3 to parent Parent(4751): Received 3 Parent(4751): Sending 3 back Parent(4751): Received 4 Parent(4751): Sending 7 back Parent(4751): Received 5 child(4753): Received 3 Parent(4751): Sending 12 back Parent(4753): Received 4 Parent(4753): Sending 7 back Parent(4753): Received 5 Parent(4753): Sending 12 back 3 4 5 -1 child(4753): Sending 3 to parent Parent(4751): Received 3 Parent(4751): Sending 3 back Parent(4751): Received 4 Parent(4751): Sending 7 Parent(4751): Received 5 child(4753): 收到 3 Parent(4751): 发回 12 Parent(4753): 收到 4 Parent(4753): 发回 7 Parent(4753): 收到 5 Parent(4753): 发回 12

From the result, the last step is Parent send 12 back but child cannot received 12 and show the total sum.从结果来看，最后一步是父发回 12 但子不能收到 12 并显示总和。 Therefore, anyone has some ideas why the result is not my expected and how to modify my code?因此，任何人都有一些想法为什么结果不是我的预期以及如何修改我的代码？

Thanks in advance.提前致谢。

1 个解决方案

Your parent process just runs to an end without waiting for the child to finish.您的父进程只是运行结束，而无需等待子进程完成。 Thus the child is killed before it can actually print a result.因此，孩子在实际打印结果之前就被杀死了。

You need to add a wait() or waitpid() in the proper place of the parent process.您需要在父进程的适当位置添加wait()或waitpid() 。

在linux中使用父进程和子进程中的Pipe - Using Pipe in parent and child process in linux

如何将管道从父进程发送到子进程 - how to send the pipe from parent to child process

Linux在C中使用管道在父进程和子进程之间传递值？ - Linux pass value between parent process and child process using pipe in c?

子进程和父进程之间使用pipe（）进行管道通信 - Pipeline Communication between Child Process and Parent Process using pipe()

用子进程和父进程写入管道 - writing to a pipe with a child and parent process

子进程和父进程之间的pipe（） - pipe() between child and parent process

从管道读取到我的子进程 - Reading from a pipe to my child process

为什么子流程管道在父流程中显示不同的管道详细信息 - Why child process pipe is showing in parent process with different pipe details

子进程如何从管道读取stdout，而父进程如何将stdin写入管道？ - How can the child process read stdout from the pipe and the parent process write stdin to the pipe?

无需管道将数据从子进程传递到父进程 - Pass data from child to parent process without pipe

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相关问题 在linux中使用父进程和子进程中的Pipe - Using Pipe in parent and child process in linux 如何将管道从父进程发送到子进程 - how to send the pipe from parent to child process Linux在C中使用管道在父进程和子进程之间传递值？ - Linux pass value between parent process and child process using pipe in c? 子进程和父进程之间使用pipe（）进行管道通信 - Pipeline Communication between Child Process and Parent Process using pipe() 用子进程和父进程写入管道 - writing to a pipe with a child and parent process 子进程和父进程之间的pipe（） - pipe() between child and parent process 从管道读取到我的子进程 - Reading from a pipe to my child process 为什么子流程管道在父流程中显示不同的管道详细信息 - Why child process pipe is showing in parent process with different pipe details 子进程如何从管道读取stdout，而父进程如何将stdin写入管道？ - How can the child process read stdout from the pipe and the parent process write stdin to the pipe? 无需管道将数据从子进程传递到父进程 - Pass data from child to parent process without pipe

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