| MAKEDEV(3) | Library Functions Manual | MAKEDEV(3) | 
makedev, major,
  minor —
#include <sys/types.h>
dev_t
  
  makedev(int
    major, int
  minor);
int
  
  major(dev_t
    dev);
int
  
  minor(dev_t
    dev);
makedev() macro allows a unique device number to be
  generated based on its major and
  minor number. The major() and
  minor() macros can be used to obtain the original
  numbers from the device number dev.
All block and character devices are uniquely identified by a pair of major and minor numbers. The major number refers to a certain device class (e.g. disks, TTYs) while the minor number identifies an instance within the device class.
major() macro returns a device major number that has
  a value between 0 and 255. The minor() macro returns a
  device minor number whose value can span the complete range of an
  int.
| April 1, 2011 | NetBSD 9.4 |