设置好keepalive以后，我们通过实验来看看当client异常退出或是网络断掉的情况下，keepalive怎么通知我们异常断开的情况。这里采用select模式，实验环境为XP系统和Win7系统，几种情况返回值如下：



1．　　正常断开

select函数正常返回，recv函数返回0



2．　　异常断开

-Set keepalive after the experiment to look at client quit unexpectedly or network broken, the keepalive how notice abnormal disconnect. Select mode, the experimental environment for XP, and Win7 system, several cases the return value is as follows:



A. Normally open

The select function returns normally, the recv function returns 0



Two. Abnormal disconnect