10.3.3 Out parameters

Out parameters (output parameters) are declared as follows:

The purpose of an out parameter is to pass values back to the calling routine: The variable is passed by reference. The initial value of the parameter on function entry is discarded, and should not be used.

If a variable must be used to pass a value to a function and retrieve data from the function, then a variable parameter must be used. If only a value must be retrieved, a out parameter can be used.

Needless to say, default values are not supported for out parameters.