typedef struct Cursorinfo Cursorinfo;typedef struct Cursor Cursor; extern ulong blanktime; struct Cursorinfo {	Lock;}; extern void	blankscreen(int);extern void	flushmemscreen(Rectangle);extern uchar*	attachscreen(Rectangle*, ulong*, int*, int*, int*);extern	int	setcolor(ulong, ulong, ulong, ulong);extern	void	getcolor(ulong, ulong*, ulong*, ulong*); #define ishwimage(i)	0