Get interface to listen on

get_interface.c

#include <pcap.h>

int main()
{
  char *dev;
  char errbuf[PCAP_ERRBUF_SIZE];
  
  dev = pcap_lookupdev(errbuf);
  
  /* Check for failure */
  if (dev == NULL) {
    fprintf(stderr, "Couldn't find a default interface: %s\n", errbuf);
    return(1); 
  }
  
  /* Success */
  printf("%s\n", dev);
  return(0); 
}