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.

REFERENCES
     etoimajor(D3), getemajor(D3), getmajor(D3), getminor(D3), makedevice(D3)