Not sure if it is the same issue but with our proxy server code with many
threads, the debugger sometimes gives AV on Wndproc when step run too.
SZ
On Sat, May 29, 2010 at 11:38 AM, Arno Garrels <arno.garr...@gmx.de> wrote:
> Hi,
>
> When new property SocketFamily is set to "sfAny" method
> DnsLookup may now return a list containing both IPv4 and IPv6
> strings. Looks like Windows always returns IPv6 first.
> The top item is also copied to string FDnsResult.
> Should I change this order?
>
> BTW.: I wrote some helper classes to emulate the
> WSAAsyncGetHostByxx functions.
> While I was testing them I got strange AV's upon debugging
> and stepping thru the multi-threaded code. Took me several days
> to prove that this is not caused by my code but either a
> debugger bug (my favorite) or some other condition (driver,
> root kit or whatsoever).
>
> I made a very simple test case which triggers the AV on different
> hardware and Windows versions in both D7 and D2010 here.
> However some German testers were not able to reproduce the issue,
> very strange.
>
>
> unit Unit1;
>
> interface
>
> uses
> Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
> Dialogs, StdCtrls;
>
> const
> WM_TEST = WM_USER + 1;
>
> type
>
> TMyThread = class(TThread)
> protected
> FWindowHandle: HWND;
> procedure Execute; override;
> public
> constructor Create(AHWnd: HWND); reintroduce;
> end;
>
> TForm1 = class(TForm)
> Memo1: TMemo;
> Button1: TButton;
> procedure Button1Click(Sender: TObject);
> private
> procedure WmTest(var Msg: TMessage); message WM_TEST;
> public
> { Public-Deklarationen }
> end;
>
> var
> Form1: TForm1;
>
> implementation
>
> {$R *.dfm}
>
> { TMyThread }
>
> constructor TMyThread.Create(AHWnd: HWND);
> begin
> FWindowHandle := AHWnd;
> inherited Create(FALSE);
> end;
>
> procedure TMyThread.Execute;
> var
> I : Integer;
> begin
> I := 0;
> while not Terminated do
> begin
> Sleep(500);
> SendMessage(FWindowHandle, WM_TEST, ThreadID, I);
> Inc(I);
> end;
> end;
>
> procedure TForm1.WmTest(var Msg: TMessage);
> begin
> Memo1.Lines.Add(IntToHex(Msg.WParam, 8) + ' ' + IntToStr(Msg.LParam));
> end;
>
> procedure TForm1.Button1Click(Sender: TObject);
> var
> Thread : TMyThread;
> I : Integer;
> begin
> IsMultiThread := TRUE;
> for I := 1 to 4 do // <== Set a break point here and repeat pressing F8
> until the AV is raised.
> Thread := TMyThread.Create(Handle);
> end;
>
> end.
>
>
>
>
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