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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 device ID, id, or
     a pointer to the device structure, dev, and return the integer 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@acns.ab.ca〉.