The standard predefined macros are specified by the C and/or C++ language standards, so they are available with all

compilers that implement those standards. Older compilers may not provide all of them. Their names all start with double underscores.

__FILE__--------------当前文件的名字

__BASE_FILE--------假设a.h被b.c包含，那么__FILE__是a.h,__BASE_FILE__是b.c。

__LINE__--------------是当前的行数