有没有一种简单的方法来清除C中的管道 [英] Is there an easy way of clearing a pipe in C

问题描述

我有一个所有子进程都使用的管道，但是在子进程使用该管道与父进程对话之前，我需要清除它，以便父进程正确地读取它. C中有一个简单的函数可以做到这一点吗?

I have a pipe that all my child processes use, but before a child uses the pipe to talk to the parent I need to clear it so that the parent reads from it correctly. Is there a simple function in C to do this?

推荐答案

清除"管道的方法是从管道中读取直到缓冲区为空.这对您没有帮助.我猜您真正的问题是父级可能读取来自多个客户端的数据.解决您的问题有两种简单的方法.

The way to "clear" a pipe is to read from it until the buffer is empty. This doesn't help you. I am guessing that your real problem is that the parent might read data that is mixed from multiple clients. There are two easy solutions to your problem.

1. 总是写少于PIPE_BUF个字节长的消息，并在一次调用write的情况下执行此操作.这将确保对管道的写入是原子的.

1. Always write messages less than PIPE_BUF bytes long, and do this in a single call to write. This will ensure that writes to the pipe are atomic.

为每个子进程使用单独的管道.在服务器端，使用线程或将非阻塞IO与select或poll一起使用.同样，您可以使用Unix域套接字，并让每个客户端都连接到套接字(这实际上是创建单独管道的另一种方式).

Use a separate pipe for each child process. On the server side, either use threads or use nonblocking IO with select or poll. Equivalently, you could use a Unix domain socket, and have each client connect to the socket (this is really just a different way of creating the separate pipes).

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