获得操作系统版本

DWORD dwVersion = GetVersion();
 // Get the Windows version.
 DWORD dwWindowsMajorVersion =  (DWORD)(LOBYTE(LOWORD(dwVersion)));
 DWORD dwWindowsMinorVersion =  (DWORD)(HIBYTE(LOWORD(dwVersion)));
 // Get the build number.
 if (dwVersion < 0x80000000)              // Windows NT/2000/XP
  return WIN_NT_2000_XP;
 else if (dwWindowsMajorVersion < 4)      // Win32s
  return WIN_32S;
 else                                     // Windows 95/98/Me
  return WIN_95_98_ME;