NAME
makedev, major,
minor —
device number conversion
SYNOPSIS
#include
<sys/types.h>
dev_t
makedev(int
major, int
minor);
int
major(dev_t
dev);
int
minor(dev_t
dev);
DESCRIPTION
Themakedev()
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.
RETURN VALUES
The 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.