此程序可以验证 closeonexec

flag 设置对可执行程

序的影响。具体实现是：已经打开的一文本文件的文件描述符

(file descr iptor) 在经过exec系统调用接口后，仍然可以在exec

执行的程序中有效。-this procedure can verify closeonexec flag settings on the impact of the executable. Realize is : have opened a text file of file descr iptors (file descr iptor) after exec - EC call interface, he can still exec in the process of implementing effective.