当您对与dup2()复制的管道文件描述符调用close()时，会发生什么情况? [英] What happens when you call close() on a pipe file descriptor that was duplicated with dup2()?

问题描述

我对Unix和C编程中的文件描述符有疑问.

I have a question regarding file descriptors in Unix and C programming.

假设我使用 pipe(fd)来获取文件描述符3和4的管道端，3连接到读取端，4连接到写入端.

Let's say I use pipe(fd) to get file descriptor 3 and 4 for the pipe ends, 3 connects to the read end and 4 to the write end.

现在，我在处理过程中使用 dup2(fd [write_end]，1)将写入端的描述符(为4)复制到文件描述符1.如果我现在执行 close(fd [write_end])，它将关闭描述符1或描述符4吗?

Now I use dup2(fd[write_end],1) to copy the descriptor of the write end (which was 4) to file descriptor 1 in my process. If I now do close(fd[write_end]) will it close descriptor 1 or descriptor 4?

推荐答案

成功调用 dup2 后，两个文件描述符均有效.

After a successful call to dup2, both file descriptors are valid.

当您随后调用 close(fd [write_end])时，由于 fd [write_end] 设置为4，因此与 close(4)相同.因此文件描述符1保持打开和可用状态.

When you then call close(fd[write_end]), because fd[write_end] is set to 4 this is the same as close(4). So file descriptor 1 remains open and usable.

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