gcc filename.c -lpcap && sudo ./a.out

#include<stdio.h>
#include<pcap.h>

int main()
{
   char errbuf[PCAP_ERRBUF_SIZE];
   pcap_if_t *alldevs;
   pcap_if_t *dev;
   pcap_findalldevs(&alldevs, errbuf);
   for (dev = (pcap_if_t *)alldevs; dev != NULL; dev = dev->next) {
     printf("Interface: ");
     if(dev->name)
        printf("Name: %10s ", dev->name);
     else
        printf("Empty Name");

     if(dev->description)
        printf("Description: %5s", dev->description);
     else
        printf("Empty Description");
     printf("\n");
   }
   printf("End!\n");
}