printing data to file in real time program RTAI using fprintf
 

Hi,
I'am new to rtai. and i'm programming in linux fedora(C). I need to compare the input(reference value) and output the actual output which is being sensed at same instant of time..So i would like to store data in a file while running the application. I understand that I cannot use "fprintf " statement to write the data to a file, since it would only increase the latency or execution time, as the program is running at kernel level. hence I request to please guide me how to write data to a file while program is running..please also mention the header files if any to be included..
Thank you in advance...

Chandu