getemajor(D3)getemajor(D3)NAMEgetemajor - 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.
DESCRIPTIONgetemajor 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.
REFERENCESetoimajor(D3), geteminor(D3), getmajor(D3), getminor(D3), makedevice(D3)
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