个人编写的一个十分好用的函数，可以设置程序成为后台守护进程，



调用十分简单，在程序中调用函数deamon即可，以下是函数原型



int daemon(int nochdir, int noclose)



其中 nochdir 为是否修改当前目录-Individual written a very useful function, you can set the program to become a background daemon, called very simple, the program can call the function deamon, the following is the function prototype int daemon (int nochdir, int noclose)　which nochdir as to whether changes current directory