DBINDEX_BLK
Name
     
       DBINDEX_BLK
Purpose
     
       Subroutine of DBINDEX to create associated variable of correct datatype
Explanation
     
       DBINDEX_BLK will offset into the file by a specified amount in 
      
       preparation for writing to the file.   V5.2 or later
Calling Sequence
     
       res = dbindex_blk(unit, nb, bsz, ofb, dtype)
Inputs
     
       unit   The unit number assigned to the file.
      
       nb     The number of blocks to offset into the file.
      
       bsz    The size of each block, in bytes, to offset into the file.
      
       ofb    The offset into the block, in bytes.
      
       dtype  The IDL datatype as defined in the SIZE function
Outputs
     
       res    The returned variable.  This is an associated variable.
Restrictions
     
       The file must have been previously opened.
Modification History
     
       Written by Michael R. Greason, STX, 14 June 1990.
      
       Converted to IDL V5.0   W. Landsman   September 1997
      
       Use 64 bit integer for very large databases  W. Landsman February 2001
      
       Added new unsigned & 64bit integer datatypes    W. Landsman July 2001