V5/usr/sys/conf.h

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including files from this version of Unix. 
struct
{
	char	d_minor;
	char	d_major;
};

struct	bdevsw
{
	int	(*d_open)();
	int	(*d_close)();
	int	(*d_strategy)();
	int	*d_tab;
} bdevsw[];
int	nblkdev;

struct	cdevsw
{
	int	(*d_open)();
	int	(*d_close)();
	int	(*d_read)();
	int	(*d_write)();
	int	(*d_sgtty)();
} cdevsw[];
int	nchrdev;