Library /sys$common/syshlp/basichelp.hlb Qualifiers, FLAG  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Tells BASIC to warn you about the use  program  elements  that  are  not
  compatible  with  BASIC-PLUS-2 or Alpha BASIC, or that Compaq designates
  as declining.

  Format

      [NO]FLAG [ { : } ( flag-clause,... ) ]
                 { = }

      flag-clause:  { [NO]BP2COMPATIBILITY }
                    { [NO]AXPCOMPATIBILITY }
                    { [NO]DECLINING        }

      /FLAG = ALL is the same as /FLAG = (BP2COMPATIBILITY, DECLINING,
      AXPCOMPATIBILITY).
      /FLAG = NONE is the same as /NOFLAG.

      The default is /FLAG = (NODECLINING, NOBP2COMPATIBILITY,
      NOAXPCOMPATIBILITY).