Basic question about IOCTL

["Mayank Kaushik" <mayank.utexas@xxxxxxxxx>]

Hi everyone,

I am puzzled about what IOCTLs are and what they are used for. I could not understand much from the the man page for ioctl. 
A description of what ioctls are used for (alongwith an example usage) would be very helpful.

Thanks in advance,
Mayank