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      Returns the item numbers and other info. for an item name.


      Procedure to return the item numbers and other information
      of a specified item name

Calling Sequence

      db_item, items, itnum, ivalnum, idltype, sbyte, numvals, nbytes


      items - item name or number
              form 1 scalar string giving item(s) as list of names
                      separated by commas
              form 2 string array giving list of item names
              form 3 string of form '$filename' giving name
                      of text file containing items (one item per
              form 4 integer scalar giving single item number or
                        integer vector list of item numbers
              form 5 Null string specifying interactive selection
                      Upon return items will contain selected items
                      in form 1
              form 6 '*' select all items


      itnum - item number
      ivalnum - value(s) number from multiple valued item
      idltype - data type(s) (1=string,2=byte,4=i*4,...)
      sbyte - starting byte(s) in entry
      numvals - number of data values for item(s)
              It is the full length of a vector item unless
              a subscript was supplied
      nbytes - number of bytes for each value
    All outputs are vectors even if a single item is requested

Optional Input Keywords

      ERRMSG = If defined and passed, then any error messages will
              be returned to the user in this parameter rather than depending
              on the MESSAGE routine in IDL. If no errors are encountered,
              then a null string is returned. In order to use this feature,
              ERRMSG must be defined first, e.g.
                              ERRMSG = ''
                              DB_ITEM, ERRMSG=ERRMSG, ...
                              IF ERRMSG NE '' THEN ...

Procedure Calls


Revision History

      Written: D. Lindler, GSFC/HRS, October 1987
      Version 2, William Thompson, GSFC, 17-Mar-1997
                      Added keyword ERRMSG
      Use STRSPLIT instead of GETTOK to parse form 1, W. Landsman July 2002
      Assume since V5.4 use FILE_EXPAND_PATH() instead of SPEC_DIR()
              W. Landsman April 2006
      Support new DB format allowing entry lengths > 32767 bytes WL Oct 2010
      Ignore blank lines in .items file WL February 2011

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