该代码是一本书上的源程序，在Linux环境下，编译调试通过，并附送了该书的电子版-The code is a book on the source, in the Linux environment, the compiler debugging through, and comes with an electronic version of the book

The __FUNCTION__ gcc variable is generally only used for debugging. If we re not using gcc, define __FUNCTION__ as a cpp symbol here. Don t define it if using a newer Windows compiler.