根据网卡名获取IP地址，以及掩码地址

    printf("%s - %s\n" , iface , inet_ntoa(( (struct sockaddr_in *) ifr.ifr_addr )- sin_addr) );

The socket used can be a TCP socket (SOCK_STREAM) as well.

If you also need the netmask then use the SIOCGIFNETMASK value in ioctl like this :

    printf("IP address of %s - %s\n" , iface , inet_ntoa(( (struct sockaddr_in *) ifr.ifr_addr )- sin_addr) );
    printf("Netmask of %s - %s\n" , iface , inet_ntoa(( (struct sockaddr_in *) ifr.ifr_addr )- sin_addr) );