Hello I have download libosip2-3.3.0 , but when I to compile sip_reg.c using "gcc sip_reg.c -o sip_reg -leXosip -L/usr/local/lib -I../../include/ -DHAVE_STRUCT_TIMEVAL -losipparser2" ,I got some error msg : sip_reg.c:55:28: error: eXosip2/eXosip.h: No such file or directory sip_reg.c: In function 'main': sip_reg.c:336: error: 'osip_message_t' undeclared (first use in this function) sip_reg.c:336: error: (Each undeclared identifier is reported only once sip_reg.c:336: error: for each function it appears in.) sip_reg.c:336: error: 'reg' undeclared (first use in this function) sip_reg.c:366: error: 'eXosip_event_t' undeclared (first use in this function) sip_reg.c:366: error: 'event' undeclared (first use in this function) sip_reg.c:385: error: 'EXOSIP_REGISTRATION_NEW' undeclared (first use in this function) sip_reg.c:388: error: 'EXOSIP_REGISTRATION_SUCCESS' undeclared (first use in this function) sip_reg.c:391: error: 'EXOSIP_REGISTRATION_FAILURE' undeclared (first use in this function) sip_reg.c:394: error: 'EXOSIP_REGISTRATION_TERMINATED' undeclared (first use in this function) how can I overcome the problem ? cheers, jay