directive

 A  directive  is  the  alternative  to  a  block  in  a  routine
 declaration.  A directive provides the compiler with information
 about either a routine whose heading is declared separately from
 its  body (indicated by the FORWARD directive) or a routine that
 is external to the Pascal program (indicated  by  the  EXTERNAL,
 EXTERN  or FORTRAN directives).  To specify a directive, include
 it immediately after the routine heading and follow  it  with  a
 semicolon.    The   following   describes  the  two  classes  of
 directives.

  o  The FORWARD directive indicates a  routine  whose  block  is
     specified  in  a  subsequent  part of the same procedure and
     function section, allowing you to call a routine before  you
     specify  its routine body.  As an extension, VSI Pascal will
     allow the body to be in a different  declaration  part.   If
     the  body  and  heading are specified in different procedure
     and function sections, a FORWARD  declared  function  should
     not be used as an actual discriminant to a schema type.

     When you specify the body of the routine in subsequent code,
     include   only   the   FUNCTION   or  PROCEDURE  predeclared
     identifier, the routine-identifier,  and  the  body  of  the
     routine.    Do   not   repeat   the   formal-parameter,  the
     attribute-list, or the result-type-id.

  o  The EXTERNAL, EXTERN and FORTRAN directives indicate that  a
     routine  is  external to a Pascal program.  They are used to
     declare independently compiled Pascal  routines  written  in
     other  languages.   For  portability  reasons,  the  FORTRAN
     directive should only be used for external routines  written
     in FORTRAN.