Mega Code Archive
Undocumented Detect If an Application Has Stopped Responding
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Title: Undocumented: Detect If an Application Has Stopped Responding
Question: In many situations you might like to detect if an application is blocked. For example while automating Word, you'd like to know if Word has stopped responding.
This article describes how to detect if an application has stopped responding using some undocumented functions.
Answer:
{
// Translated from C to Delphi by Thomas Stutz
// First published at www.SwissDelphiCenter.com
// Original Code:
// (c)1999 Ashot Oganesyan K, SmartLine, Inc
// mailto:ashot@aha.ru, http://www.protect-me.com, http://www.codepile.com
The code doesn't use the Win32 API SendMessageTimout function to
determine if the target application is responding but calls
undocumented functions from the User32.dll.
-- For Windows 95/98/ME we call the IsHungThread() API
The function IsHungAppWindow retrieves the status (running or not responding)
of the specified application
IsHungAppWindow(Wnd: HWND): // handle to main app's window
BOOL;
-- For NT/2000/XP the IsHungAppWindow() API:
The function IsHungThread retrieves the status (running or not responding) of
the specified thread
IsHungThread(DWORD dwThreadId): // The thread's identifier of the main app's window
BOOL;
Unfortunately, Microsoft doesn't provide us with the exports symbols in the
User32.lib for these functions, so we should load them dynamically using the GetModuleHandle and
GetProcAddress functions:
}
// For Win9x/ME
function IsAppRespondig9x(dwThreadId: DWORD): Boolean;
type
TIsHungThread = function(dwThreadId: DWORD): BOOL; stdcall;
var
hUser32: THandle;
IsHungThread: TIsHungThread;
begin
Result := True;
hUser32 := GetModuleHandle('user32.dll');
if (hUser32 0) then
begin
@IsHungThread := GetProcAddress(hUser32, 'IsHungThread');
if Assigned(IsHungThread) then
begin
Result := not IsHungThread(dwThreadId);
end;
end;
end;
// For Win NT/2000/XP
function IsAppRespondigNT(wnd: HWND): Boolean;
type
TIsHungAppWindow = function(wnd:hWnd): BOOL; stdcall;
var
hUser32: THandle;
IsHungAppWindow: TIsHungAppWindow;
begin
Result := True;
hUser32 := GetModuleHandle('user32.dll');
if (hKernel 0) then
begin
@IsHungAppWindow := GetProcAddress(hUser32, 'IsHungAppWindow');
if Assigned(IsHungAppWindow) then
begin
Result := not IsHungAppWindow(wnd);
end;
end;
end;
function IsAppRespondig(Wnd: HWND): Boolean;
begin
if not IsWindow(Wnd) then
begin
ShowMessage('Incorrect window handle');
Exit;
end;
if Win32Platform = VER_PLATFORM_WIN32_NT then
Result := IsAppRespondigNT(wnd)
else
Result := IsAppRespondig9X(GetWindowThreadProcessId(wnd,nil));
end;
// Example: Check if Word is hung/responing
procedure TForm1.Button3Click(Sender: TObject);
var
Res: DWORD;
h: HWND;
begin
// Find Word by classname
h := FindWindow(PChar('OpusApp'), nil);
if h 0 then
begin
if IsAppRespondig(h) then
ShowMessage('Word is responding')
else
ShowMessage('Word is not responding');
end
else
ShowMessage('Word is not open');
end;
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