pcap_lookupdev(3) find the default device on which to capture


#include <pcap/pcap.h>

char errbuf[PCAP_ERRBUF_SIZE];

char *pcap_lookupdev(char *errbuf);


pcap_lookupdev() returns a pointer to a string giving the name of a network device suitable for use with pcap_create() and pcap_activate(), or with pcap_open_live(), and with pcap_lookupnet(). If there is an error, NULL is returned and errbuf is filled in with an appropriate error message. errbuf is assumed to be able to hold at least PCAP_ERRBUF_SIZE chars.