subroutine hec_online
c
c This is the routine which controls the online running mode
c of hec_adc. The purpose of this mode is to use hec_adc standard 
c routines for signal reconstruction, pedestal evaluation, etc. 
c to fill several histograms which are useful to the testbeam shift
c crew. It does this as quickly as possible by fast filling histograms
c and using only one loop over the data. It can be run on existing
c data files or files which are in the process of being written by the
c testbeam DAQ. 
c
c Online mode is designed to either be entered from the command 
c line (by typing hec_adc) or from a script as determined by the 
c "autorun" datacard. This allows scripts to be written which control 
c system-dependent things (eg. printer commands) allowing the fortran
c code in hec_adc to remain completely f77-compliant.  
c
      implicit none
c
c user datacard values common
c
      include'hec_par.inc'      !shared parameters
      include'hec_datacard.inc' ! datacard values
      include'hec_online.inc'   ! online common
      include'hec_tdc.inc'      ! tdc value
c
c enter online mode if requested
c
      if (run_mode .ne. 2) return
c
      print *, ' *** starting online analysis'
c
c initialize for online running
c
      call hec_online_ini
c
c start main menu (prompt user for run number to analyze)
c
      irun = -1
c
      do while (irun .ne. 0)
c
c get file name to analyze and check for its existence
c
        call hec_online_getfile
c
c if file found, start hec_adc analysis
c
        if (runfile .and. irun .ne. 0) then
c
          print *, ' *** Found data file ',infname, 
     +             ' starting analysis'
c
c initialize arrays for this run
c
          call hec_online_run_ini
c
c get the maximum number of events to process
c
          call hec_online_getnevt
c
c get trigger request from user (what do they want to see)
c
          call hec_online_gettrig
c
c in order to book histograms run header info is needed
c make a quick pass to get it
c
          call hec_runh_pass
c
c quick pass on data to get slow control infos if requested
c
          call hec_slow_pass
c
c set the tdc wrap around constant for this run
c
          call hec_tdc_ini
c 
c monitoring may modify the wac values with the values put inside 
c onlinescr/online.scr
c
          tdc_wac_c   = cr_tdc_wac_c
          tdc_wac_epi = cr_tdc_wac_epi
          tdc_wac_mu  = cr_tdc_wac_mu
c
c inform the user about the current tdc correction
c
          if (irunpd .ge. 7) then 
            print *,' '
            print *, ' *** monitoring may modify tdc wac:' 
            print *, ' *** tdc wac actually used:'
            print *, '     wac_c         = ', tdc_wac_c
            print *, '     wac_epi       = ', tdc_wac_epi
            print *, '     wac_mu        = ', tdc_wac_mu
          endif
c
c book online histograms that are filled event by event
c
          call hec_his_ini
c
c pass over data
c
          call hec_online_pass1
c
c open online histogram file and allow viewing of histos
c
          call hec_online_ter
c
        endif
c
c if program is in "autorun" mode, do not request more than one consecutive
c run, the controlling script will do that for you
c
        if (auto_run .ge. 1) then
          irun = 0
        endif
c
      enddo
      end