NAME:    
	write_diffmag_dbd
  PURPOSE: 
	produce a dbd file so that a diffmag database can be created
	(called by diffmag_wfc)
  CALLING SEQUENCE: 
	write_diffmag_dbd, db[,maxentries=maxentries]
  OPTIONAL INPUT KEYWORDS: 
	maxentries: maximum number of entries in the database. Default is 10000
  OUTPUTS: 
    	db: string, name of output database. 
  EXAMPLE: 
	write_diffmag_dbd,'dbase/diffmag_wfci'
  DEPENDENCIES: 
	
  RESTRICTIONS: 
        UNTESTED
  CALLED PROCEDURES AND FUNCTIONS: 
	astrolib functions
  MODIFICATION HISTORY: 
     	10-Nov-2000  Original by S. Aigrain

(See /home/xmmssc/soft/idl/pro/wfcqc/write_diffmag_dbd.pro)