23.4 Special Considerations for Handling Strings with
          DECwindows Motif
  All strings passed between DECwindows Motif and your
  program must be null terminated. For example:
  "A string" + "0"C

  When passing a string argument to a DECwindows Motif
  routine, the address of the string is required. For static
  strings, the address of the string can easily be obtained with
  the LOC function. For example:
  COMMON (c1) STRING hierarchy_file_name = 21
  hierarchy_file_name = "BASIC$HELLOMOTIF.UID" + "0"C
  DECLARE LONG hierarchy_file_name_array(1)
  hierarchy_file_name_array(0) = LOC (hierarchy_file_name)

  Because dynamic strings are described by a descriptor, a dif-
  ferent means is needed to get the address of the string text.
  The following helper function will get the address of dynamic
  strings as well as static strings:
  FUNCTION LONG ADDRESS_OF_STRING (STRING str_arg BY REF)
      OPTION TYPE=EXPLICIT, INACTIVE=SETUP
  END FUNCTION (LOC (str_arg))

  Example of passing a dynamic string to a DECwindows
  Motif routine:
  DECLARE STRING temp_string
  temp_string = "A string value" + "0"C
  list_test = DXmCvtFCtoCS (ADDRESS_OF_STRING (temp_string), &
          byte_count, istatus)