Qt文档给出了这样的解释：
> QProcess :: start：
Starts the given program in a new process,if none is already running,
passing the command line arguments in arguments.
> QProcess :: startDetached：
Starts the program program with the arguments arguments in a new
process,and detaches from it.
两者有什么区别？区别的只是你可以使用QProcess :: start和使用QProcess :: startDetached的许多实例只启动一个程序实例吗？
