SONGetMarkData

  SONGETMARKDATA returns the timings and marker values for a Marker, AdcMark,
  RealMark or TextMark channel

  Implemented through SONGetMarkData.dll

  [npoints, times, markers]=
              SONGETMARKDATA(fh, chan, maxpoints, stime, etime{, filtermask})

             INPUTS: FH = file handle
                     CHAN = channel number 0 to SONMAXCHANS-1
                     MAXPOINTS = Maximum number of data values to return
                                 (up to 32767, if zero will be set to
                                    32767)
                     STIME  = the start time for the data search
                                    (in clock ticks)
                     ETIME = the end time for teh search
                                     (in clock ticks)
                     FILTERMASK  if present is  a filter mask structure
                                    There will be no filtering if this is
                                    absent.
            OUTPUTS: NPOINTS= number of data points returned
                                or a negative error
                     TIMES = an NPOINT column vector containing the
                                timestamps (in clock ticks)
                     DATA = an NPOINT x 4 byte array, with 4 markers
                            for each of the timestamps in TIMES.

  Note: For easier compatability with version 1.0 of the library use a
  structure for the outputs e.g.
  [npoints, data.timings, data.markers]=
                          SONGETMARKDATA(fh, chan, maxpoints, stime, etime)

  For error codes, see the CED documentation

  Author:Malcolm Lidierth
  Matlab SON library:
  Copyright © The Author & King's College London 2005-2006