DIB sections

[CornedBee]

Why does this code produce an access violation at the CopyMemory line?

bool CDbBitmap::BmpToDibSec(BYTE *pData)
{
	PBITMAPFILEHEADER pBMFH = (PBITMAPFILEHEADER)pData;
	ASSERT(pBMFH->bfType == 0x4D42);		// check again if really BMP
	
	DWORD dwBitOffset = pBMFH->bfOffBits;
	BITMAPINFO *pbi = (BITMAPINFO*)(pData + sizeof(BITMAPFILEHEADER));
	// Create the DIB section
	BYTE *pBits;
	HBITMAP hB = ::CreateDIBSection(NULL, pbi, DIB_RGB_COLORS, (PVOID*)&pBits, NULL, 0);
	::CopyMemory(pBits, pData + dwBitOffset, pBMFH->bfSize - dwBitOffset);
	Attach((HGDIOBJ)hB);
	return true;
}

pData is a pointer to memory which contains a complete BMP file. CreateDIBSection should allocate memory and set pBits to point to this memory.
I tried using HeapSize to get the block size of pBits but since it is allocated by the system it fails.

[jim mcnamara]

You cannot call ::CreateDIBSection(NULL....);
Rather than NULL it has to have a valid DC handle--usually from CreateCompatibleDC.

If you can do it that way, it's news to me, anyway.
CreateDIBSection is failing. No memory allocated.

[CornedBee]

As described in Petzold's Programming Windows I need the dc handle only if I use DIB_PAL_COLORS.
Also, the function returns a bitmap handle (not NULL) and pBits isn't NUL either. (Both would be NULL if the function failed).

There are some news for you
I know that there is memory, I just think it's not enough.