getemajor(D3) getemajor(D3)
NAME
getemajor - get external major device number
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
major_t getemajor(dev_t dev);
Arguments
dev External device number.
DESCRIPTION
getemajor returns the external major number given a device
number, dev.
Return Values
The external major number.
USAGE
External major numbers are visible to the user. Internal
major numbers are only visible in the kernel. Since, on some
architectures, the range of major numbers may be large and
sparsely populated, the kernel keeps a mapping between
external and internal major numbers to save space.
All driver entry points are passed device numbers using
external major numbers.
Usually, a driver with more than one external major number
will have only one internal major number. However, some
system implementations map one-to-one between external and
internal major numbers. Here, the internal major number is
the same as the external major number and the driver may have
more than one internal major number.
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
getemajor(D3) getemajor(D3)
REFERENCES
etoimajor(D3), geteminor(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