void CWnd::CenterWindow(CWnd* pAlternateOwner) small (?) bug [modified]

[Cristian Amarie]

Not really a question, but rather signaling a MFC pitfall... wincore.cpp, approx. line 3152 (Visual C++ 6.0, SP6) void CWnd::CenterWindow(CWnd* pAlternateOwner) { ASSERT(::IsWindow(m_hWnd)); // determine owner window to center against DWORD dwStyle = GetStyle(); HWND hWndCenter = pAlternateOwner->GetSafeHwnd(); if (pAlternateOwner == NULL) { ... Seems to me that pAlternateOwner calls first GetSafeHwnd, then is tested if is NULL... -- modified at 1:55 Monday 7th August, 2006

[Michael Dunn]

GetSafeHwnd() works fine if pAlternateOwner is null:

HWND CWnd::GetSafeHwnd() const { return this == NULL ? NULL : m_hWnd; }

If the this object is NULL, it just returns NULL.

--Mike-- Visual C++ MVP :cool: LINKS~! Ericahist | PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

[Hamid Taebi]

Is pAlternateOwner valid?

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WhiteSky

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[Cristian Amarie]

Correct, I didn't checked. Sorry about that.

[Cristian Amarie]

Can be NULL or not, but Mike Dunn corrected me. GetSafeHwnd returns NULL if "this" is NULL. A little bit strange to me to have CWnd *pAlternateOwner = NULL; HWND hwndAlternate = pAlternateOwner->GetSafeHwnd(); // NULL because pAlternateOwner is NULL

[David Crow]

Cristian Amarie wrote:

HWND hWndCenter = pAlternateOwner->GetSafeHwnd();

GetSafeHwnd() is an inline function, so there's nothing to dereference.

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