getIP() on Mac

getIP.h

#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>

static string getIP(){
    int fd;
    struct ifreq ifr;
    fd = socket(AF_INET, SOCK_DGRAM, 0);
    ifr.ifr_addr.sa_family = AF_INET;
    strncpy(ifr.ifr_name, "en0", IFNAMSIZ-1);
    ioctl(fd, SIOCGIFADDR, &ifr);
    close(fd);
    string ipAddress = inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr);
    //[*] check good ipAddress
    int pos = ipAddress.find_last_of(".");
    string last = ipAddress.substr(pos+1);
    if ((pos==string::npos )|| (last == "0")) ipAddress = ""; 
    return ipAddress;
}