C++获取hostname&IP&MAC地址

#include <ifaddrs.h>
#include <sys/ioctl.h> 
#include <net/if.h> 
#include <string.h> 
#include <stdio.h>
#include <unistd.h>
#include <netdb.h>
#include <arpa/inet.h>

char* getMac(char* mac,char* dv){
    struct   ifreq   ifreq; 
    int   sock; 
    if(!mac || !dv)
        return mac;
    if((sock=socket(AF_INET,SOCK_STREAM,0)) <0) {
        perror( "socket "); 
        return mac; 
    } 
    strcpy(ifreq.ifr_name,dv); 
    if(ioctl(sock,SIOCGIFHWADDR,&ifreq) <0) { 
        perror( "ioctl "); 
        return mac; 
    } close(sock);
     sprintf(mac, "%02x:%02x:%02x:%02x:%02x:%02x", 
            (unsigned char)ifreq.ifr_hwaddr.sa_data[0], 
            (unsigned char)ifreq.ifr_hwaddr.sa_data[1], 
            (unsigned char)ifreq.ifr_hwaddr.sa_data[2], 
            (unsigned char)ifreq.ifr_hwaddr.sa_data[3], 
            (unsigned char)ifreq.ifr_hwaddr.sa_data[4], 
            (unsigned char)ifreq.ifr_hwaddr.sa_data[5]);
     return mac;
 }

int main (int argc, const char * argv[])
{
    char hname[128];
    struct hostent *hent;
    int i;

    gethostname(hname, sizeof(hname));

    //hent = gethostent();
    hent = gethostbyname(hname);

    printf("\n\n\n");

    char mac[30];
    struct ifaddrs * ifAddrStruct=NULL;
    void * tmpAddrPtr=NULL;

    getifaddrs(&ifAddrStruct);

    while (ifAddrStruct!=NULL) {
        if (ifAddrStruct->ifa_addr->sa_family==AF_INET) { // check it is IP4
            // is a valid IP4 Address
            tmpAddrPtr=&((struct sockaddr_in *)ifAddrStruct->ifa_addr)->sin_addr;
            char addressBuffer[INET_ADDRSTRLEN];
            inet_ntop(AF_INET, tmpAddrPtr, addressBuffer, INET_ADDRSTRLEN);
            printf("%s IP: %s\n", ifAddrStruct->ifa_name, addressBuffer);
            printf("MAC: %s\n\n",getMac(mac,ifAddrStruct->ifa_name));
        } else if (ifAddrStruct->ifa_addr->sa_family==AF_INET6) { // check it is IP6
            // is a valid IP6 Address
            tmpAddrPtr=&((struct sockaddr_in *)ifAddrStruct->ifa_addr)->sin_addr;
            char addressBuffer[INET6_ADDRSTRLEN];
            inet_ntop(AF_INET6, tmpAddrPtr, addressBuffer, INET6_ADDRSTRLEN);
            printf("%s IP: %s\n", ifAddrStruct->ifa_name, addressBuffer); 
            printf("MAC: %s\n\n",getMac(mac,ifAddrStruct->ifa_name));
        } 
        ifAddrStruct=ifAddrStruct->ifa_next;
    }
    return 0;
}