C++: Trying to hook a message box and change its position - c++

Question

I recently started coding in C++ and I am very new to it. (I code in Javascript, PHP, Java and Obj-C more often)
I'm practicing how to hook a message box and change its position. This is what I have in my .cpp file (after reading this SO post).
#include <iostream>
#pragma comment(lib,"User32.lib")
#include <windows.h>
HHOOK hhookCBTProc = 0;
LRESULT CALLBACK pfnCBTMsgBoxHook(int nCode, WPARAM wParam, LPARAM lParam){
if (nCode == HCBT_CREATEWND)
{
CREATESTRUCT *pcs = ((CBT_CREATEWND *)lParam)->lpcs;
if ((pcs->style & WS_DLGFRAME) || (pcs->style & WS_POPUP))
{
HWND hwnd = (HWND)wParam;
SetWindowPos(hwnd, HWND_TOP,130,122, 0, 0,SWP_NOSIZE);
}
}
return (CallNextHookEx(hhookCBTProc, nCode, wParam, lParam));
}
int main(void)
{
hhookCBTProc = SetWindowsHookEx(WH_CBT,pfnCBTMsgBoxHook,
0, GetCurrentThreadId());
int sResult = MessageBox ( NULL, "Hooked!", "oh my", MB_OK );
UnhookWindowsHookEx(hhookCBTProc);
return 0;
}
For some reason the position of the message box isn't changing. Where did it go wrong?
(I know I can create a customized window or dialog. But I am doing it this way because I want to learn how to hook a message box and where I did wrong.)

Answer 1

Firstly you should check in the debugger that your hook is actually being called, if you haven't already.
Secondly, at the time the HCBT_CREATEWND hook event is triggered, the window has only just been created - the system has yet to size and position it. It will do this with the values in the CREATESTRUCT after the hook returns - overriding your SetWindowPos call.
See the docs from MSDN on the lParam value for this particular hook event:
Specifies a long pointer to a CBT_CREATEWND structure containing
initialization parameters for the window. The parameters include the
coordinates and dimensions of the window. By changing these
parameters, a CBTProc hook procedure can set the initial size and
position of the window.
Therefore, the correct way to use this hook to change a window's position is to modify the values in the CREATESTRUCT directly.
Also note that it's quite possible that the dialog manager sizes and positions the window after creation, so if you find that this still isn't working for you, you may need to try watching for the HCBT_MOVESIZE event instead.

Answer 2

From the docs
At the time of the HCBT_CREATEWND notification, the window has been
created, but its final size and position may not have been determined
and its parent window may not have been established.
Maybe try hooking into CBT_ACTIVATE instead.