Use a wrapper to build a C++ Dll that calls a C++ .lib and Use the Dll is LabView

Hi All,
I need to access some functions in a C++ .lib within LabView, but has no source code for the library. Can I build a Dll in Visual C++ that calls this library, then have LabView calls the Dll? If so, how different is building this Dll compared to building a Dll from a .cpp file? I am new to C++, could some one suggest how to use the .lib in Visual C++ 6.0 studio to build the Dll?
Thanks for your help.
Bryan

BryanL wrote:
Hi Rolf, thanks for the info. I will try to build a vi to call that function. For a more immediate need, I can use a downloaded vi that calls SetActiveWindow function, then use its output windowshandle to find the window name with a lvwuser32.dll function. The problem is this find window name function vi requires a windows reference input, which does not take the window handle output from the SetActiveWindow vi. How do i convert the window handle into a reference number? Thanks again.
Don't try to write a VI to call that function. That function requires a callback function pointer, something that is more or less impossible (well you can get it done but it is not worth the trouble) to create in LabVIEW. You will need an external DLL that does the enumeration and returns an array of strings to LabVIEW.
The lvwuser32.dll also just uses window handles. Look inside those VIs and you should see that those window references are typecasted into uint32 and then passed to the Call Library Node if I remember correctly. You definitely should be able to typecast the (probably uint32) you get from your other function into the window reference that that VI takes. The window reference of the lvutil library is just a nice trick to make it refnum like so that you can not inadvertly wire something else to it (and confuse/crash Windows).
Rolf Kalbermatter
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

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