Trying to set up a thread specifc hook in MFC

Question

I am trying to capture some keyboard messages in a child window that's attached to a dialog.

I am getting an error trying to install the hook.

Error C2440: 'reinterpret_cast' : cannot convert from 'LRESULT (__stdcall CMyClass::* )(int,WPARAM,LPARAM)' to 'HOOKPROC'

below is my code

In .h

HHOOK m_hHook;

LRESULT CALLBACK GetMsgProc(int code, WPARAM wParam, LPARAM lParam);

In .cpp

m_hHook = SetWindowsHookEx(WH_GETMESSAGE, (HOOKPROC)(&CMyClass::GetMsgProc), AfxGetInstanceHandle, NULL);

LRESULT CALLBACK CMyClass:GetMsgProc(int code, WPARAM wParam, LPARAM lParam)

{

// implementation

}

can anyone help me point out what I am doing wrong?

Answer 1

On 8/23/2012 5:10 PM, tigersuen wrote:

I am trying to capture some keyboard messages in a child window that's attached to a dialog.

I am getting an error trying to install the hook.

Error C2440: 'reinterpret_cast' : cannot convert from 'LRESULT (__stdcall CMyClass::* )(int,WPARAM,LPARAM)' to 'HOOKPROC'

The hook procedure must be a standalone non-member function, or else a static member function. It cannot be a non-static member function of any class.

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Igor Tandetnik

Answer 2

You are right, so I tried to add static to my function

static LRESULT CALLBACK GetMsgProc(int code, WPARAM wParam, LPARAM lParam);

Now I get this error

error C2664: 'SetWindowsHookExA': cannot convert parameter 3 from 'HINSTANCE (__stdcall *)(void)' to 'HINSTANCE'

Answer 3

On 8/23/2012 6:31 PM, tigersuen wrote:

Now I get this error

error C2664: 'SetWindowsHookExA': cannot convert parameter 3 from 'HINSTANCE (__stdcall *)(void)' to 'HINSTANCE'

The third parameter should be AfxGetInstanceHandle(). You are missing a pair of parentheses. You want to actually call the function and pass its return value, but instead you are trying to pass the address of the function.

---

Igor Tandetnik

Answer 4

You are absolutely right.

I am very sorry for this careless mistake.