geteminor(D3) geteminor(D3)
NAME
geteminor - get external minor device number
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
minor_t geteminor(dev_t dev);
Arguments
dev External device number.
DESCRIPTION
geteminor returns the external minor number given a device
number, dev.
Return Values
The external minor number.
USAGE
External minor numbers are visible to the user. Internal
minor numbers are only visible in the kernel. Since, on some
architectures, a driver can support more than one external
major device that maps to the same internal major device, the
kernel keeps a mapping between external minor numbers and
internal minor numbers to allow drivers to index arrays more
easily. For example, a driver may support two devices, each
with five minor numbers. The user may see each set of minor
numbers numbered from zero to four, but the driver sees them
as one set of minor numbers numbered from zero to nine.
All driver entry points are passed device numbers using
external minor numbers.
Systems that map external major device numbers one-to-one with
internal major numbers also map external minor numbers one-
to-one with internal minor numbers.
Level
Initialization, Base or Interrupt.
Synchronization Constraints
Does not sleep.
Driver-defined basic locks, read/write locks, and sleep locks
may be held across calls to this function.
Copyright 1994 Novell, Inc. Page 1
geteminor(D3) geteminor(D3)
REFERENCES
etoimajor(D3), getemajor(D3), getmajor(D3), getminor(D3),
makedevice(D3)
NOTICES
Portability
All processors
Applicability
ddi: 1, 2, 3, 4, 5, 5mp, 6, 6mp, 7, 7mp
Copyright 1994 Novell, Inc. Page 2