IN  PRTL_BITMAP BitMapHeader,
  IN  ULONG StartingIndex,
  IN  ULONG Length

Routine Description:

    This procedure determines if the range of specified bits are all clear.


    BitMapHeader - Supplies a pointer to the previously initialized bitmap.

    StartingIndex - Supplies the starting bit index to examine

    Length - Supplies the number of bits to examine

Return Value:

    BOOLEAN - TRUE if the specified bits in the bitmap are all clear, and
        FALSE if any are set or if the range is outside the bitmap or if
        Length is zero.