experimental unit for zw_GetSystemTimeAsFileTime

// http://codereview.stackexchange.com/questions/110819/delphi-convenience-wrapper-for-getsystemtimepreciseasfiletime

unit UTestGSTAFT_v1;

interface

uses
   {$ifdef VER150} Windows {$else} WinAPI.Windows {$endif};

procedure zw_GetSystemTimeAsFileTime (var ft: TFileTime);  stdcall;

implementation

procedure GSTAFT_AutoInit_ (var ft: TFileTime); stdcall; forward;

type
   TGetSystemTimeAsFileTime = procedure (var ft: TFileTime); stdcall;

var
   GetSystemTimeAsFileTime_: TGetSystemTimeAsFileTime = GSTAFT_AutoInit_;

procedure zw_GetSystemTimeAsFileTime (var ft: TFileTime);  stdcall;
begin
   GetSystemTimeAsFileTime_(ft);
end;

{$ifdef VER150}
function InterlockedCompareExchangePointer (var dst: Pointer; new_val, cmp_val: Pointer): Pointer;
stdcall; external kernel32 name 'InterlockedCompareExchange';
{$endif}

procedure GSTAFT_AutoInit_ (var ft: TFileTime); stdcall;
var
   fp: TFarProc;
begin
   fp := GetProcAddress(GetModuleHandle('kernel32'), 'GetSystemTimePreciseAsFileTime');
   if fp = nil then
      fp := @GetSystemTimeAsFileTime;
   InterlockedCompareExchangePointer(Pointer(@GetSystemTimeAsFileTime_), fp, @GSTAFT_AutoInit_);
   GetSystemTimeAsFileTime_(ft);
end;

end.