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# Unsupplied Value

Value > Special Data Values > Unsupplied Value

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The Unsupplied class implements the value used to initialize unsupplied keyword parameters to functions.

There is one distinguished instance of the Unsupplied class in the reserved system variable unsupplied .

You can test to see whether a caller has supplied an optional keyword argument by comparing it with unsupplied .

Constructor

    Unsupplied

EXAMPLE
    fn testFunction arg1 optionalArg2: =
    (
      if optionalArg2 == unsupplied then
        format "Optional Argument Was Not Supplied!\n"
      else
        format "Arguments Were Supplied, Their Sum Was %!\n" (arg1+optionalArg2)
    )

    testFunction 10.0
    --> Optional Argument Was Not Supplied!

    testFunction 10.0 optionalArg2:32
    --> Arguments Were Supplied, Their Sum Was 42.0!

#### See Also

- Creating Functions

- Function Calls

- MAXScript FAQ: What is the difference between 'undefined' and 'unsupplied' values?

- Special Data Values