已知：
CreateFile返回的是HANDLE，
fopen返回的是FILE *,
_open返回的是个int,
转换：
1、FILE * => int
Gets the file descriptor associated with a stream.
int _fileno(
FILE *stream
);
2、int => HANDLE
Returns operating-system file handle associated with existing low-level file descriptor.
long _get_osfhandle(
int fd
);
3、HANDLE => int
Associates a C run-time file descriptor with an existing operating-system file handle.
int _open_osfhandle (
intptr_t osfhandle,
int flags
);
4、FILE * => int
应该就是FILE结构中的_file字段。