How to pass range of interest to UDF

I am advised that a UDF can be made more efficient by passing the "range of interest" to the UDF instead of making it volatile. Refer thread:

http://www.excelforum.com/excel-prog...ml#post2319512

However I do not know how to pass the range of interest to the UDF. Can someone please help?

The UDF:

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Many thanks in advance
Asha

You would add a further input variable to the UDF and then pass the additional variable to the UDF from the cell call.

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called for ex. along lines of:

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