Get list of interfaces in FreeBSD, detect which ones are loopbacks

interfaces.c

/* compile with cc -o interfaces interfaces.c */
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <net/if.h>

int main() {
	struct ifaddrs *ifap;
	if( getifaddrs(&ifap) < 0 ) {
		perror("getifaddrs returned an error:");
		exit(1);
	}
	while( ifap != NULL ) {
		printf("%s %x",ifap->ifa_name,ifap->ifa_flags);
		if( ifap->ifa_flags & IFF_LOOPBACK ) printf(" LOOPBACK");
		printf("\n");
		ifap = ifap->ifa_next;
	}
	freeifaddrs(ifap);
}