LabVIEW has the ability, by using the Call Library Function, to call DLLs. There are examples that come with LabVIEW that show how the function is used. There are some gotchas, however. For one, LabVIEW does not support all data types. As a starting point, I would refer you to the "Using External Code in LabVIEW" manual. With LabVIEW 6, it comes as a .pdf file. I think it's also available on NI's web site.