CODE:

void GetLocalMAC(char *buf)
{
IP_ADAPTER_INFO *IpAdaptersInfo =NULL;
IP_ADAPTER_INFO *IpAdaptersInfoHead =NULL;

IpAdaptersInfo = (IP_ADAPTER_INFO *) GlobalAlloc(GPTR, sizeof(IP_ADAPTER_INFO ));

if (IpAdaptersInfo == NULL)
{
  return;
}

DWORD dwDataSize = sizeof( IP_ADAPTER_INFO );
DWORD dwRetVal = GetAdaptersInfo(IpAdaptersInfo,&dwDataSize);

if ( ERROR_SUCCESS != dwRetVal)
{
  GlobalFree( IpAdaptersInfo );
  IpAdaptersInfo = NULL;

if( ERROR_BUFFER_OVERFLOW == dwRetVal)
  {
   IpAdaptersInfo =(IP_ADAPTER_INFO *) GlobalAlloc( GPTR, dwDataSize );
   if (IpAdaptersInfo == NULL)
   {
    return;
   }
   if ( ERROR_SUCCESS != GetAdaptersInfo( IpAdaptersInfo, &dwDataSize ))
   {
    GlobalFree( IpAdaptersInfo );
    return;
   }

}
  else
  {
   return;
  }

}

//Save the head pointer of IP_ADAPTER_INFO structures list.
IpAdaptersInfoHead = IpAdaptersInfo;

do{
  if (IsLocalAdapter(IpAdaptersInfo->AdapterName))
  {
   sprintf(buf,"%02x-%02x-%02x-%02x-%02x-%02x",
    IpAdaptersInfo->Address[0],
    IpAdaptersInfo->Address[1],
    IpAdaptersInfo->Address[2],
    IpAdaptersInfo->Address[3],
    IpAdaptersInfo->Address[4],
    IpAdaptersInfo->Address[5]);
   //
   break;
  }

IpAdaptersInfo = IpAdaptersInfo->Next;

}while (IpAdaptersInfo);

if (IpAdaptersInfoHead != NULL)
{
  GlobalFree( IpAdaptersInfoHead );
}
}

BOOL IsLocalAdapter(char *pAdapterName)
{
BOOL ret_value = FALSE;

#define NET_CARD_KEY _T("System//CurrentControlSet//Control//Network//{4D36E972-E325-11CE-BFC1-08002BE10318}")
char szDataBuf[MAX_PATH+1];
DWORD dwDataLen = MAX_PATH;
DWORD dwType = REG_SZ;
HKEY hNetKey = NULL;
HKEY hLocalNet = NULL;

if(ERROR_SUCCESS != RegOpenKeyEx(HKEY_LOCAL_MACHINE, NET_CARD_KEY, 0, KEY_READ, &hNetKey))
  return FALSE;
wsprintf(szDataBuf, "%s//Connection", pAdapterName);
if(ERROR_SUCCESS != RegOpenKeyEx(hNetKey ,szDataBuf ,0 ,KEY_READ, &hLocalNet))
{
  RegCloseKey(hNetKey);
  return FALSE;
}
if (ERROR_SUCCESS != RegQueryValueEx(hLocalNet, "MediaSubType", 0, &dwType, (BYTE *)szDataBuf, &dwDataLen))
{
  goto ret;
}
if (*((DWORD *)szDataBuf)!=0x01)
  goto ret;
dwDataLen = MAX_PATH;
if (ERROR_SUCCESS != RegQueryValueEx(hLocalNet, ";PnpInstanceID", 0, &dwType, (BYTE *)szDataBuf, &dwDataLen))
{
  goto ret;
}
if (strncmp(szDataBuf, ";PCI", strlen(";PCI")))
  goto ret;

ret_value = TRUE;

ret:
RegCloseKey(hLocalNet);
RegCloseKey(hNetKey);

return ret_value;
}