modifier
open stream with referents-allowed defaulting { string expression } ... as attachment open stream with referents-allowed defaulting { string expression1, string expression2 } ... as attachment reopen stream with referents-allowed defaulting { string expression } ... as attachment reopen stream with referents-allowed defaulting { string expression1, string expression2 } ... as attachment set stream with referents-allowed defaulting { string expression } to ... set stream with referents-allowed defaulting { string expression1, string expression2 } to ...
This modifier allows a programmer to provide a definition (default value) for every referent that is written
out. A defaulting
declaration can be specified with referents-allowed
in an
open
, reopen
, or set
action. There are two possible forms, either as one string
expression or two, and these provide an effective value for referents as follows:
The defaulting
part used to provide the effective value of an undefined referent is the
defaulting
part associated with the final destination of the referent.