This question was answered in KnowledgeBase article 0GJ7T7ZL:
Since LabWindows/CVI doesn't have functions to do interrupt handling, the only way for a CVI application to respond to an interrupt is through a Windows 16-bit DLL (for Win 3.1) or a 32-bit DLL (for Win NT/9x/2000). You will need to develop a device driver to handle the interrupt. Use a compiler that supports interrupt handling such as Borland C++ or Visual C++ and upon getting the interrupt, use the Windows API function PostMessage to post a message to the CVI window. In CVI, use the function RegisterWinMsgCallback to set up a callback function to be executed anytime the message is received by CVI.
It is important to note that you will have to write a different driver for Win 9x/2000 and NT, because the OSs in
terrupt handling functions are different.
