get mouse coordinates when user press Ctrl and click - c++

Question

I want to get mouse click coordinates X and Y when user press Ctrl and click at same time.
User may click anywhere on the screen or programs. I want my program to catch the event and get coordinates when Ctrl key is down pressed and mouse click occurs at same time. I want to get system coordinates X and Y, not the window coordinates of other programs.
I'm using C++ .
How to do that ?
Windows OS, WIN API code
I'm doing next which is not working:
HHOOK MouseHook;
LRESULT CALLBACK MouseHookProc(int nCode, WPARAM wParam, LPARAM lParam){
PKBDLLHOOKSTRUCT k = (PKBDLLHOOKSTRUCT)(lParam);
POINT p;
if(wParam == WM_RBUTTONDOWN)
{
// right button clicked
GetCursorPos(&p);
//p.x
//p.y
//my program is never getting here, why ?
}
}
MouseHook = SetWindowsHookEx(WH_MOUSE_LL,(HOOKPROC)MouseHookProc,0,0);
if I change the above line to: MouseHook = SetWindowsHookEx(WH_MOUSE,(HOOKPROC)MouseHookProc,GetModuleHandle(NULL),0);
then it will work only for my own program window, but not hooking clicks outside of my program

Answer 1

Have you read this article? link
First of all, if you want to catch system entire mouse + keyboard event, your hooking function must be placed on a dll.
1)If nCode is less than zero, the hook procedure must return the value returned by CallNextHookEx.
Like below,
if(nCode < 0)
{
CallNextHookEx(hook, nCode, wParam, lParam);
return 0;
}
If CallNextHookEx is not called, there is a chance that other processes that have installed hook may not get the events correctly.
2)And then, check nCode again, whether it is HC_ACTION.
switch (nCode)
{
case HC_ACTION:
...
3)Finally, you can check WPARAM for WM_RBUTTONDOWN, and LPARAM for MSLLHOOKSTRUCT

Answer 2

The way I would approach is I would create a global variable say
int ctrl_pressed = 0
/*
0 -- ctrl nt pressed
1 -- Crtl Pressed
*/
Step 1: Now I would handle both WM_KEYDOWN and WM_KEYUP for ctrl
Step 2: In the callback of WM_KEYDOWN (if lparam is ctrl ) I would set ctrl_pressed to 1.
And in case of WM_KEYUP I would set ctrl_pressed to 0.
Step 3: Now Finally ill handle WM_MOUSECLICKED
and then check if ctrl_pressed(global) is 1 , which if true I can just get the coordinates.
This is just an approach may be not the most efficient solution.
Wait for more experienced WIN32 Developers to give their input on this.