ioccom.h question

[Chris Humphries <chumphries@drauku.net>]

Hello developers,
      
      Wondering for those that know what src/sys/sys/ioccom.h is all
 about, I was wondering if you could help enlighten me to what _IOC
 is doing? i see the code and the bit shifting to get values, yet am
 now sure exactly what it is doing. 
      From looking at apmd source, trying to figure out why it is not
 working correctly (the problem being it not returning the correct data
 and missing), i noticed that it on following the path, that _IOC is how
 i get data about the hardware? noticed from doing a grep for _IOR, it
 is used in alot of places. Also want to try to get info on the misc 
 buttons on my laptop, so i can map them to actions (like volume buttons).

      Just could use help on what _IOC is doing, as it seems greek atm,
 so _any_ helpful enlightenment would be.. well.. helpful.


Thanks,
Chris

 -- 
"Anyone who considers arithmetical methods of producing random digits is, 
 of course, in a state of sin."