;+
; NAME:
;  openmysql
; PURPOSE:
;  Open a mySQL database for operations via a pipe.
; DESCRIPTION:
; CATEGORY:
;  Database
; CALLING SEQUENCE:
;  openmysql,lun,dbname
; INPUTS:
;  dbname - Name of database to open at start.
; OPTIONAL INPUT PARAMETERS:
; KEYWORD INPUT PARAMETERS:
; OUTPUTS:
;  lun - the logical unit of the pipe (use free_lun to close).
;  error  - return value indicating if the open call succeeded.  If error is
;            zero, the open was good and the lun is ready for use.  If error
;            is not zero, the lun will not point to an open file and the
;            !error_state system variable will contain more information if
;            you want it.
; KEYWORD OUTPUT PARAMETERS:
; COMMON BLOCKS:
; SIDE EFFECTS:
; RESTRICTIONS:
;  Assumes that your .my.cnf file points to the correct mysql server and that
;    it includes the login information.  Also, the command 'mysql' must appear
;    in your default path.
; PROCEDURE:
; MODIFICATION HISTORY:
;  Written by Marc W. Buie, Lowell Observatory, 2002/01/09
;  2006/12/08, MWB, added error output argument, now can indicate if open failed
;-
pro openmysql,lun,dbname,error

   self = 'OPENMYSQL: '
;   if badpar(lun,[0,2,3],0,caller=self+'(lun) ') then return
;   if badpar(dbname,7,0,caller=self+'(dbname) ') then return

   cmd = 'mysql -u root -pmysql -B -q -n '+dbname
   spawn,cmd,unit=lun

   catch,error

   if error ne 0 then begin
      print,self,!error_state.msg
      print,self,'Unable to open database ',dbname,', closing pipe and quitting.'
      free_lun,lun
      catch,/cancel
      return
   endif
   ; This command is needed to trigger the catch and facilitate closing
   ;   of the lun.  We don't need these results, just the activity on the pipe.
   mysqlcmd,lun,'show tables;',result,nlines, DEBUG=1
   ;stop
end