Dear Sir, If anyone get this letter, let me know, i am just confuse why its not working. 1. pjsua_acc_id acc_id; // create no error 2. All rest related pjsua_* // cause this compile error [root at example lib]# gcc -Wall /home/sun/Downloads/mysip/myapp.c /home/sun/Downloads/mysip/myapp.c: In function ?main?: /home/sun/Downloads/mysip/myapp.c:29: warning: implicit declaration of function ?error_exit? /home/sun/Downloads/mysip/myapp.c:21: warning: unused variable ?acc_id? /tmp/ccbVD6Mv.o: In function `main': myapp.c:(.text+0x1b): undefined reference to `pjsua_verify_sip_url' myapp.c:(.text+0x3a): undefined reference to `error_exit' collect2: ld returned 1 exit status [root at example lib]# Thank you Best regards Shamun -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20100731/8616555c/attachment.html>