What is warning number C4238?

[Chuck Le Mieux]

Found the following on Microsofts Visual C++ Technical Support.

Compiler Warning (level 4) C4238
nonstandard extension used : class rvalue used as lvalue
This error occurs when you are using Microsoft language extensions (/Ze) and
use a class type as is an rvalue in a context that implicitly or explicitly
takes its address. For example:
struct C
{
C();
};
C * pC = &C(); // yields C4238
This usage is not permitted by the C++ Working Paper, and in some cases
(such as the example above) can be quite dangerous. This usage is being
permitted under /Ze for compatibility with previous versions of the
compiler, which did not flag this error. This usage is not permitted under
/Za.

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Thomas Blenkers wrote in message
<3450AB49...@anachem.ruhr-uni-bochum.de>...
>Hello out there,
>
>following you find a sniplet of my code for painting an owner drawn list
>control inside a MFC-CListCrtl-derived class having the ingenious name
>CMyListCrtl ;)
>
>
>void CMyListCrtl::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
>{
> CDC* pDC = CDC::FromHandle(lpDrawItemStruct->hDC);
> int nItem = lpDrawItemStruct->itemID;
> CRect rcHighlight;
> GetItemRect(nItem, rcHighlight, LVIR_LABEL);
>
> // The next line causes warning C4238
> pDC->FillRect(rcHighlight, &CBrush(::GetSysColor(COLOR_HIGHLIGHT)));
>}
>
>Compiling this code with MSVC 5.0 in release mode and warning level 4 I
>get a warning with the number C4238: non-standard-extension R-value
>used as L-value (I have the german version, so I'm sure the exact phrase
>is slightly different).
>
>What have I done, and what should be done better?
>
>Feel free to post and mail your answers.
>
>WM_THANKSALOT
> Thomas Blenkers