GET_INFO(MARKER_VARIABLE)

  For an overview of the GET_INFO built-in, see the HELP topic GET_INFO.

  The following strings can be used for parameter2 when parameter1 is a
  marker variable:

  Parameter 2     | Return Value  (Parameter 1 is a marker variable)
  ----------------+----------------------------------------------------------
  "before_bol"    | (1 or 0) - Indicates whether the marker is located
                  |            before the beginning of a line.  The return
                  |            value has no meaning if "beyond_eob" is true.
  "beyond_eob"    | (1 or 0) - Indicates whether the marker is located
                  |            beyond the end of a buffer.
  "beyond_eol"    | (1 or 0) - Indicates whether the marker is located
                  |            beyond the end of a line.  The return value
                  |            has no meaning if "beyond_eob" is true.
  "bound"         | (1 or 0) - Indicates whether the marker is attached
                  |            to a character or is free.
  "buffer"        | Buffer   - Buffer in which the marker is located.
  "display_value" | Integer  - The display value associated with the
                  |            record containing the specified marker.
                  |            For more information on display values,
                  |            see SET(DISPLAY_VALUE) and
                  |            SET(RECORD_ATTRIBUTE) in DECTPU HELP.
  "left_margin"   | Integer  - Current left margin setting of the line
                  |            containing the marker.
  "middle_of_tab" | (1 or 0) - Indicates whether the marker is located
                  |            in the middle of a tab.  The return value
                  |            has no meaning if "beyond_eob" is true.
  "offset"        | Integer  - Number of character positions between the first
                  |            character of the record and the marker location.
  "offset_column" | Integer  - Number of screen columns between the beginning
                  |            of the current record and the marker location.
  "record_number" | Integer  - The record number of the line containing the
                  |            specified marker.
  "right_margin"  | Integer  - Current right margin setting of the line
                  |            containing the marker.
  "unmodifiable_  | (1 or 0) - Returns 1 if the line containing the marker
  records"        |            is unmodifiable, 0 otherwise.
  "video"         | Keyword  - Video attribute of the marker; returns NONE
                  |            if the marker was created with the parameter
                  |            FREE_MARKER.
  "within_range"  | (1 or 0) - Indicates whether the marker is in the range
                  |            specified by parameter3.  Note that parameter3
                  |            must be a range variable specifying the range
                  |            to be searched.
  +---------------+--------------------------------------------------------+