If you are just starting your development, I would highly recommend beginning with the DAQmx API instead of the Traditional DAQ one. DAQmx is our new API which is much easier to use than Traditional DAQ and also has performance improvements as well. Here's where you can find the some ANSI C DAQmx examples:
C:\Program Files\National Instruments\NI-DAQ\Examples\DAQmx ANSI C\
-Jack