How can I check if keybd_event was successful? - delphi

Question

I have this code right here that modifies the clipboard and then restores it back:
function SetClipText(szText:WideString):Boolean;
var
pData: DWORD;
dwSize: DWORD;
begin
Result := FALSE;
if OpenClipBoard(0) then
begin
dwSize := (Length(szText) * 2) + 2;
if dwSize <> 0 then
begin
pData := GlobalAlloc(MEM_COMMIT, dwSize);
if pData <> 0 then
begin
CopyMemory(Pointer(pData), #szText[1], dwSize - 2);
if SetClipBoardData(CF_UNICODETEXT, pData) <> 0 then
Result := TRUE;
end;
end;
CloseClipBoard;
end;
end;
function GetClipText(var szText:WideString):Boolean;
var
hData: DWORD;
pData: Pointer;
dwSize: DWORD;
begin
Result := FALSE;
if OpenClipBoard(0) then
begin
hData := GetClipBoardData(CF_UNICODETEXT);
if hData <> 0 then
begin
pData := GlobalLock(hData);
if pData <> nil then
begin
dwSize := GlobalSize(hData);
if dwSize <> 0 then
begin
SetLength(szText, (dwSize div 2) - 1);
CopyMemory(#szText[1], pData, dwSize);
Result := TRUE;
end;
GlobalUnlock(DWORD(pData));
end;
end;
CloseClipBoard;
end;
end;
var
OldClip : WideString;
begin
repeat until GetClipText (OldClip);
repeat until SetClipText ('NewClipBoardText');
// PASTE
keybd_event(VK_CONTROL, MapVirtualKey(VK_CONTROL, 0), 0, 0);
keybd_event(Ord('V'), MapVirtualKey(Ord('V'), 0), 0, 0);
keybd_event(Ord('V'), MapVirtualKey(Ord('V'), 0), KEYEVENTF_KEYUP, 0);
keybd_event(VK_CONTROL, MapVirtualKey(VK_CONTROL, 0), KEYEVENTF_KEYUP, 0);
repeat until SetClipText (OldClip);
end.
I use keybd_event to paste new clipboard text to a window (e.g. notepad).
It seems like that keybd_event is so fast, that repeat until SetClipText (OldClip); get's called before the keys got pressed. Is there way to check when and if the keys were pressed?

Answer 1

keybd_event never fails. It merely places they event that you specify into the currently active input queue.
Because the function is asynchronous the keyboard event is not processed until the other application gets round to processing it. So, most likely the other application has not processed the keyboard event by the time you call SetClipText. You can't expect to know when a particular keyboard event is processed, unless you have control of the other application. But in that case you would not be communicating with it by faking input.