CODEWITHSUNDEEP
delphihookkeyboard-events
alvaroc
alvaroc

Reputation: 472

Delphi correct signature for LowLevelKeyboardProc()

I´m writing a global keyboard hook in Delphi 2007 and Windows 10. I´ve found different signatures for a Delphi LowLevelKeyboardProc callback. Someones like this and windows documentation (https://learn.microsoft.com/es-es/previous-versions/windows/desktop/legacy/ms644985(v=vs.85))
LowLevelKeyboardProc() never is executed
prompt that lparam is a pointer to a TKBDLLHOOKSTRUCT record.
Other ones however (http://www.delphifaq.com/faq/delphi_windows_API/f512.shtml and https://www.swissdelphicenter.ch/en/showcode.php?id=1722), show 

function KeyHookFunc(Code, VirtualKey, KeyStroke: Integer): LRESULT; stdcall;

completely ignoring the TKBDLLHOOKSTRUCT record pointer.
Which one is correct?
I'm guessing the first one is the correct one but I need to be sure. I´ve been using such signature but when I call another Function in the same unit (and DLL) passing lParam it causes Access Violation when accessing it. All functions and procedures within the DLL use stdcall

Upvotes: 1

Views: 325

Answers (1)

Sertac Akyuz
Sertac Akyuz

Reputation: 54792

All of the callback declarations are correct, although the latter two links do not give examples of LowLevelKeyboardProc but KeyboardProc. IOW, they are not low level keyboard hooks.

Note the latter two wouldn't work in 64 bits due to Integer usage instead of WPARAM, LPARAM and LRESULT.

Upvotes: 1

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