如何生成机器唯一ID

// TO COMPILE: cl machineid.cc /EHsc advapi32.lib
#include 
#include 
using namespace std;
#include 
#include 
#include 

void main() {
// 从机器CPU和网卡产生机器唯一ID
unsigned __int32 machine_id[4];

// 获取CPU vender ID和序列码, 参考 http://www.sandpile.org/ia32/cpuid.htm.
unsigned __int8 vendor_id[12] = "unknown";
unsigned __int32 serial_number[4] = {0, 0, 0, 0};
try {
  __asm {
    mov eax, 0
      cpuid
      mov dword ptr vendor_id[0], ebx
      mov dword ptr vendor_id[4], edx
      mov dword ptr vendor_id[8], ecx
      mov eax, 3
      cpuid
      mov dword ptr serial_number[0], eax
      mov dword ptr serial_number[1], edx
      mov dword ptr serial_number[2], ebx
      mov dword ptr serial_number[3], ecx
  }
} catch (...) {
  // 不是所有CPU都支持CPUID指令
}

machine_id[0] = serial_number[0] ^ *(reinterpret_cast(vendor_id));
machine_id[1] = serial_number[1] ^ *(reinterpret_cast(vendor_id + 3));
machine_id[2] = serial_number[2] ^ *(reinterpret_cast(vendor_id + 6));
machine_id[3] = serial_number[3] ^ *(reinterpret_cast(vendor_id + 8));

// 获取网卡物理地址，参考http://msdn.microsoft.com/en-us/library/ms797780.aspx
HKEY key;
if (!SUCCEEDED(::RegOpenKeyA(HKEY_LOCAL_MACHINE, "software\\Microsoft\\Windows NT\\CurrentVersion\\NetworkCards", &key))) {
  cout << "Cannot open software\\Microsoft\\Windows NT\\CurrentVersion\\NetworkCards";    return;  }  int adapter_index = 0;  do {    size_t buffer_size = 40;    LONG result = ERROR_SUCCESS;    char* key_name = new char[buffer_size];    do {      result = ::RegEnumKeyA(key, adapter_index++, key_name, buffer_size);      if (result == ERROR_MORE_DATA) {        delete[] key_name;        key_name = new char[buffer_size *= 2];      } else {        break;      }    } while (true);    if (!SUCCEEDED(result) || result == ERROR_NO_MORE_ITEMS) {      delete[] key_name;      break;    }    HKEY sub_key;    if (!SUCCEEDED(::RegOpenKeyA(key, key_name, &sub_key))) {      cout << "Cannot open " << buffer_size =" 40;" adapter_name =" new" file_handle =" ::CreateFileA(device_name," query =" OID_802_3_PERMANENT_ADDRESS;" mac_size =" sizeof(mac_address);">(mac_address));
      machine_id[(adapter_index + 1) % 4] ^= *(reinterpret_cast(mac_address + 1));
      machine_id[(adapter_index + 2) % 4] ^= *(reinterpret_cast(mac_address + 2));
      machine_id[(adapter_index + 3) % 4] ^= *(reinterpret_cast(mac_address + 1));
    }
  }
  delete[] key_name;
} while (true);
::RegCloseKey(key);

cout <<>