Problem in IoCreateSymbolicLink

I am new into device driver programming. I tried to compile the Ramdisk sample
program supplied along with Winnt 4.0 DDK. I am not able to find the library
file needed for IoCreateSymbolicLink command. The include file ntddk.h is
provided. Can any one clearly explain it to me how to compile that particular
project or the library file that needed to be added for this. I am getting
undefined symbol error.
Thanks and Regards
Rana