What is DAQmx_Val_SynchronousEventCallbacks?

[Travis G.]

Hello Stefan,

From what I understand, there is no specific messages you need to be processing.  By just continuously processing messages by "peeking" at all Windows messages, Windows will interpret the messages and perform the appropriate actions.  I would look into the following document and the MSDN for information on processing Windows messages.

An Overview of DAQ Events and Occurrences

Regards,
Travis G.
Applications Engineering
National Instruments
www.ni.com/support

[bilalD]

Hello Stephan

synchronous callbacks will basically fire in the same thread that registered the callback. The driver will marshall the callback to fire in the correct thread. Typically you would use this option if you were writing a Win32 function and wanted to access UI controls from the callback thread. Instead of you having to worry about the thread, you would register the callback in the UI thread.

You don't need to handle any custom message. You just need to make sure your thread is pumping messages. You wont need your own windproc to handle anything special. The DAQ library takes care of that for you.

The only thing this option does is affect which thread the callback will fire in.