getifaddrs()

[Edgar Pettijohn]

This is somewhat a continuation of my previous question about max 
interfaces.  I wanted to know how much space I needed for a buffer using 
ioctl(). Then I discovered getifaddrs()

I'm not sure if I'm doing something wrong or this is the correct 
output.  I have this sample code:

#include <sys/types.h>
#include <sys/socket.h>

#include <stdio.h>
#include <stdlib.h>
#include <ifaddrs.h>

int
main(int argc, char *argv[])
{
        struct ifaddrs  *ifaddr, *ifa;
        int             i;

        if (getifaddrs(&ifaddr) < 0)
        {
                printf("\ngetifaddr failed\n");
                exit(1);
        }

        for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next)
        {
                printf("%s\n", ifa->ifa_name);
        }

        freeifaddrs(ifaddr);
        return 0;
}

When compiled and ran I get this:

$ ./test
lo0
lo0
lo0
lo0
em0
iwn0
iwn0
enc0
pflog0

But ifconfig only shows one of each interface. Why is getifaddrs() 
giving me 4 lo0 and 2 iwn0?


Thanks in advance.