Parameterizing Function arguments

[rajpes]

I read the below line in qtp help.
"
You cannot use the Data Driver to parameterize the values of arguments for
user-defined methods or VBScript functions.
"


Now what exactly it means? i created a function like below and used datatable method to pass values from global sheet successfully !

Code:

Function f(param)
msgbox param
End Function

Call f(datatable("col1",dtglobal))