getemajor(D3DK) —

.IX \f4getemajor\fP(D3DK)

NAME

getemajor − get external major device number .IX major device number, external

SYNOPSIS

#include <sys/types.h>
#include <sys/ddi.h>
major_t getemajor(dev_t dev);

ARGUMENTS

devExternal device number.

DESCRIPTION

getemajor returns the external major number given a device number, dev. External major numbers are visible to the user. Internal major numbers are only visible in the kernel. Since 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.

RETURN VALUE

The external major number.

LEVEL

Base or Interrupt.

NOTES

Does not sleep.

Driver-defined basic locks, read/write locks, and sleep locks may be held across calls to this function.

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