linux c 获取本地MAC地址

#include   <stdio.h>
#include   <sys/ioctl.h>
#include   <sys/socket.h>
#include   <netinet/in.h>
#include   <net/if.h>
#include   <string.h>

int   main(int   argc,   char   *argv[])
{

struct   ifreq   ifreq;
int   sock;

if(argc!=2)
{
printf( "Usage   :   ethname\n ");
return   1;
}
if((sock=socket(AF_INET,SOCK_STREAM,0)) <0)
{
perror( "socket ");
return   2;
}
strcpy(ifreq.ifr_name,argv[1]);
if(ioctl(sock,SIOCGIFHWADDR,&ifreq) <0)
{
perror( "ioctl ");
return   3;
}
printf( "%02x:%02x:%02x:%02x:%02x:%02x\n ",
(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   0;
}