#define	setcontext(u)	_setmcontext(&(u)->mc)#define	getcontext(u)	_getmcontext(&(u)->mc)typedef struct mcontext mcontext_t;typedef struct ucontext ucontext_t;struct mcontext{	int	r[16];}; struct ucontext{	struct {		void *ss_sp;		uint ss_size;	} uc_stack;	sigset_t uc_sigmask;	mcontext_t mc;}; void makecontext(ucontext_t*, void(*)(void), int, ...);int swapcontext(ucontext_t*, ucontext_t*);int _getmcontext(mcontext_t*);void _setmcontext(mcontext_t*);