Can't store HWND in class?

I was having some strange problems with my windows app and I finally found out that the handle to my main window, stored in a class, is somehow becoming null. Apparently, something I'm doing is a no-no, but I can't explain it. For example:

Code:

class Winbase
{
public:
//...
private:
  HWND m_hwnd;
};

bool Winbase::Init(HINSTANCE hinst, WNDPROC WinProc)
{
//...
HWND m_hwnd = CreateWindowEx(0,m_wc.lpszClassName,"A window",WS_OVERLAPPEDWINDOW|WS_SYSMENU,
  0,0,GetSystemMetrics(SM_CXMAXIMIZED),GetSystemMetrics(SM_CYMAXIMIZED),
	0,0,hinst,0);

Test();
if(!m_hwnd)
    MessageBox(NULL,"Handle is bad","In Init()",MB_OK);
//...
}

void Winbase::Test()
{
if(!m_hwnd)
    MessageBox(NULL,"Handle is bad","In Test()",MB_OK);
}

The code above produces the message box titled "In Test()" but not a message box titled "In Init()". It seems the handle is valid only as long as I'm in the Init() function (after CreateWindowEx), but I don't understand why

I'm probably wrong but it could be because you are declaring the variable again in Init()

Code:

bool Winbase::Init(HINSTANCE hinst, WNDPROC WinProc)
{
//...
/*HWND*/ m_hwnd = CreateWindowEx(0,m_wc.lpszClassName,"A window",WS_OVERLAPPEDWINDOW|WS_SYSMENU,
  0,0,GetSystemMetrics(SM_CXMAXIMIZED),GetSystemMetr  ics(SM_CYMAXIMIZED),
	0,0,hinst,0);

Test();
if(!m_hwnd)
    MessageBox(NULL,"Handle is bad","In Init()",MB_OK);
//...
}

I would say something like that should have produced an error :s

I guess I was staring at that code too long last night. I thought there was something really simple but I just couldn't see it heh