device_ids(9)

NAME

device_ids, major, minor, umajor, uminor - calculate device

ids

SYNOPSIS

#include <sys/types.h>
#include <sys/systm.h>
int
major(struct cdev *dev);
int
minor(struct cdev *dev);
int
umajor(dev_t id);
int
uminor(dev_t id);

DESCRIPTION

The device_ids family of functions take either the raw de

vice ID, id, or
a pointer to the device structure, dev, and return the inte

ger value that
is the major or minor device ID as requested.

The actual major and minor device IDs are values masked from

of the raw
device ID. For details on the actual calculations used to

determine the
major or minor IDs see the actual source in kern_conf.c.

RETURN VALUES

An integer greater than zero and less than NUMCDEVSW.

major() and
minor() will return NODEV if the device is invalid.

AUTHORS

This manual page was written by Chad David <davidc@ac

ns.ab.ca>.

BSD June 22, 2004

BSD