title: SetupDiGetClassDevs causing error on XP, app built in VS2010, on Win7
body: <p>I'm writing a WPF app that uses PINVOKE to make calls to a dll that I'm also writing. In one of the exported functions in the dll, the SetupDiGetClassDevs is called. At this point, when running the app on XP, I get an error, first of all a dialog box saying:</p>
  
  <p>"The procedure entry point RegOpenKeyExW could not be located in the dynamic link library KERNAL32.dll."</p>
  
  <p>Clicking ok then leads me to an unhandled exception dialog. Both the WPP app and the dll are built with VS2010 on a Win7 machine, and the app runs fine on Win7 systems. The problem only happens when running the app on XP. If I avoid the SetupDiGetClassDevs (and subsequent SetUpdi function calls) in the dll, then nothing goes wrong; so it seems the PINVOKE mechanism is working ok.</p>
  
  <p>Any ideas what is going wrong? I'm a bit confused about seeing RegOpenKeyExW referenced, as the dll is not built with UNICODE enabled.</p>
  
  <p>Thanks
  Tom</p>