File access mode.

File access mode
Access modes of a file or directory.This is similar to F_OK, R_OK, W_OK, X_OK in unistd.h. However, as F_OK == 0, which is not very helpful when cooperates with other modes.
#define	FILE_MODE_EXIST   1<<4
	Test for existence.
#define	FILE_MODE_DIRECTORY   1<<3
	Test whether the 'file' is directory.
#define	FILE_MODE_READ   1<<2
	Test for read permission.
#define	FILE_MODE_WRITE   1<<1
	Test for write permission.
#define	FILE_MODE_EXECUTE   1
	Test for execute permission.