Nios II issue

Hi,

I am using Altera Stratix FPGA ,Quartus 10.1 version and Nichestack IP for TCP/IP communication.

here in a while loop where i am doing some processing ,i want to measure time .

for that I am putting alt_timestamp_start()and alt_timestamp( ) functions.

besides regular header files I am adding "sys/alt_timestamp.h" and "alt_types .h" header files.

but it is showing error as unrefrenced variable to these functions.

i want to know which header files i have to add for these functions?

Thanks in advance.

regards:

sblrde