检测无阻塞插座上的闭合连接 [英] Detect closed connection on non blocking socket

问题描述

非常抱歉，如果我的问题是重复的，但是我没有在网站上找到有用的信息.

I'm really sorry if my question is a duplicate, but I didn't find useful infos in the site.

我正在使用非阻塞套接字和select().如何检测客户端是否在非阻塞套接字上关闭了连接?我看到当没有可用数据读取以及连接关闭时，read()会以errno = EWOULDBLOCK返回-1.

I'm using non blocking sockets and a select(). How can I detect if a client closed the connection on non-blocking socket? I saw that a read() returns -1 with errno = EWOULDBLOCK when no datas are available to be read and also when a connection is closed.

如何区分上述情况?

推荐答案

对等方关闭连接后:

1. select()将返回可读的套接字.
2. 套接字上的 recv()或 read()将返回零.

1. select() will return the socket as readable.
2. A recv() or read() on the socket will return zero.

我看到当没有可用数据读取时，read()返回-1且errno = EWOULDBLOCK

I saw that a read() returns -1 with errno = EWOULDBLOCK when no datas are available to be read

正确，但连接未关闭.

以及连接关闭时.

and also when a connection is closed.

不，你没有.那是不对的.它返回零.

No you didn't. That's not correct. It returns zero.

如何区分上述情况?

How can I discriminate above cases?

它们是不同的，并且它们以不同的方式表现出来.

They aren't the same, and they don't manifest themselves in the same way.

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