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  IMPLEMENTATION
 
  [ USES      Clause ]
  [ LABEL     Declarations ]
  [ CONST     Declarations ]
  [ TYPE      Declarations ]
  [ VAR       Declarations ]
  [ PROCEDURE Declarations ]
  [ FUNCTION  Declarations ]
 
  END │ \aStatement Block
 
  Description
 
    The implementation section of a unit contains the definitions of
    procedures and functions declared in the interface section of
    the unit. The implementation section can also contain the
    declaration of labels, constants, types, variables, functions,
    and procedures for the internal use of the unit. These internal
    declarations are private and are not accessible to the program
    using the unit.
 
    Note the optional statement block at the end of the declarations.
    This statement block exists to contain any initialization code
    that the unit's services require. This feature sets a unit apart
    from a mere library. For instance, it could contain code that sets
    interrupt vectors. It could also contain code that handles error
    conditions or any other house-cleaning chores that the unit's
    services might require.
 
    The run-time system executes a unit's initialization code the first
    time it encounters the unit's name in a uses clause. It only
    executes the initialization code once. This is true even if a unit
    appears in more than one uses clause.
 
  See also:  INTERFACE, UNIT, USES