The VSI Pascal compiler accepts programs  that  conform  to  two
  standards  and  a  subset  of programs that comply with a third.
  Also, VSI Pascal provides features that  are  not  part  of  any
  standard  (called extensions).  If you require portable code, do
  not use the VSI Pascal extensions.

  The unextended Pascal standards are as follows:

   o  American National Standard ANSI/IEEE770X3.97-1989 (ANSI)

   o  International Standard ISO 7185-1989 (ISO)

  VSI Pascal accepts programs that conform to either standard.

  The Extended Pascal standards are as follows:

   o  American National Standard ANSI/IEEE 770X3.160-1989 (ANSI)

   o  International Standard ISO 10206-1989 (ISO)

  The two Extended Pascal standards  are  identical  in  function.
  Extended   Pascal   is  a  superset  of  the  unextended  Pascal
  standards.

  Since VSI Pascal supports many -- but not all -- Extended Pascal
  standard  features,  it  cannot compile all programs that comply
  with Extended Pascal.