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.

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