判断是否是64位操作系统

在看一个外国佬的代码的时候，看到一个API函数，然后随手查了查MSDN，原来是新加的用来判断是否是Win64位系统的，于是写了一个函数用来判断是否是64位操作系统：

代码 1 function IsWin64: Boolean;
2 var
3 Kernel32Handle: THandle;
4 IsWow64Process: function(Handle: Windows.THandle; var Res: Windows.BOOL): Windows.BOOL; stdcall;
5 GetNativeSystemInfo: procedure(var lpSystemInfo: TSystemInfo); stdcall;
6 isWoW64: Bool;
7 SystemInfo: TSystemInfo;
8 const
9 PROCESSOR_ARCHITECTURE_AMD64 = 9;
PROCESSOR_ARCHITECTURE_IA64 = 6;
begin
Kernel32Handle := GetModuleHandle('KERNEL32.DLL');
if Kernel32Handle = 0 then
Kernel32Handle := LoadLibrary('KERNEL32.DLL');
if Kernel32Handle <> 0 then
begin
IsWOW64Process := GetProcAddress(Kernel32Handle,'IsWow64Process');
GetNativeSystemInfo := GetProcAddress(Kernel32Handle,'GetNativeSystemInfo');
if Assigned(IsWow64Process) then
begin
IsWow64Process(GetCurrentProcess,isWoW64);
Result := isWoW64 and Assigned(GetNativeSystemInfo);
if Result then
begin
GetNativeSystemInfo(SystemInfo);
Result := (SystemInfo.wProcessorArchitecture = PROCESSOR_ARCHITECTURE_AMD64) or
(SystemInfo.wProcessorArchitecture = PROCESSOR_ARCHITECTURE_IA64);
end;
end
else Result := False;
end
else Result := False;
end;

需要注意是GetNativeSystemInfo 函数从Windows XP 开始才有， 而 IsWow64Process 函数从 Windows XP with SP2 以及 Windows Server 2003 with SP1 开始才有。 所以使用该函数的时候最好用GetProcAddress