member function as WndProc?

quote:

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Original post by Magmai Kai Holmlor
There''s one small problem with that method, which may or maynot affect you:
The problem is, Windows call''s the WndProc with several messages (e.g. WM_CREATE) _when you create the window - before you can possibly toss a pointer in the GWL_USERDATA spot.

There may be a better way, but this is the hack I worked out:
When the CreateWindow method is invoked, it takes a critical section and stuffs the context pointer (this) in a static pointer hole, if the GWL_USERDATA is null, the default WndProc calls defers to the static pointer. After the GWL_USERDATA is set, it nulls the static pointer and leaves the critical section.

Part of the class is a map from the windows message to the method that handles it (requires a method pointer).

Magmai Kai Holmlor
- Not For Rent

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Original post by GayleSaver
I wonder why you don''t just pass it in as the lparam and call SetWindowLong on WM_CREATE?

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Original post by Homer Simpson
One thing I do not understand, how I can use a cast "from" a
long to myclass ????
CGLWindow* pWindow = (CGLWindow*)GetWindowLong( hWnd, GWL_USERDATA );

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quote:

---

Original post by Magmai Kai Holmlor
There's one small problem with that method, which may or maynot affect you:
The problem is, Windows call's the WndProc with several messages (e.g. WM_CREATE) _when you create the window - before you can possibly toss a pointer in the GWL_USERDATA spot.

There may be a better way, but this is the hack I worked out:
When the CreateWindow method is invoked, it takes a critical section and stuffs the context pointer (this) in a static pointer hole, if the GWL_USERDATA is null, the default WndProc calls defers to the static pointer. After the GWL_USERDATA is set, it nulls the static pointer and leaves the critical section.

Part of the class is a map from the windows message to the method that handles it (requires a method pointer).

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// cbtdemo.cpp : Defines the entry point for the application.

//


#include "stdafx.h"

// this pointer in a real application

const long TEST_THIS_VALUE = 0x847FF3B9;

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	long lThis = GetWindowLong(hwnd, GWL_USERDATA);
	if (lThis != TEST_THIS_VALUE)
	{
		MessageBox(hwnd, _T("This sample doesn't work"), _T("Error"), MB_OK);
	}

	if (msg == WM_DESTROY)
	{
		PostQuitMessage(0);
		return 0;
	}

	return DefWindowProc(hwnd, msg, wParam, lParam);
}

LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam)
{
	// This hook is for our thread only, so don't check if the window being created

	// is the one we want to hook -- it is.


	if (nCode == HCBT_CREATEWND)
	{
		SetWindowLong(HWND(wParam), GWL_USERDATA, TEST_THIS_VALUE);
	}

	return 0;
}

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
 	// TODO: Place code here.


	WNDCLASS wc = { 0, WndProc, 0, 4, hInstance, LoadIcon(0, IDI_APPLICATION), LoadCursor(0, IDC_ARROW), HBRUSH(COLOR_WINDOW), 0, _T("cbtdemo") };
	if (!RegisterClass(&wc))
		DebugBreak();

	HHOOK hHook = SetWindowsHookEx(WH_CBT, CBTProc, 0, GetCurrentThreadId());
	HWND hwnd = CreateWindow(_T("cbtdemo"), _T("Testing CBT hooks"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, 0, 0, hInstance, 0);
	UnhookWindowsHookEx(hHook);

	return 0;
}