Hi All, I am using the sl_send_reply function in the receive.c file. In included the header file sl_funcs.h correctly in the receive.c and receive. compiles fine. But when in gcc LD phase it gives the error CC (gcc) [kamailio] cfg.tab.o LD (gcc) [kamailio] kamailio receive.o: In function `send_denial': /home/varun/EP1.0/kamailio-4.1.3_src/kamailio-4.1.3/receive.c:365: undefined reference to `sl_send_reply' collect2: ld returned 1 exit status make: *** [kamailio] Error 1 Please can anybody let me know why this error is coming. If more info is needed I can provide that. Thanks Varun