C / C++ / MFC

Michael Dunn wrote:

The big thing, which you just ran into, is casting pointers to a 32-bit type such as DWORD. You should use DWORD_PTR instead. The _PTR doesn't mean "pointer" (it's a bad choice of name IMO but we're stuck with it), it means "same size as a pointer" - so 32 bits in x86 and 64 bits in x64.

<br />
int  nScreenWidth =:: GetSystemMetrics(SM_CXSCREEN);<br />
int  nScreenHeight =:: GetSystemMetrics(SM_CYSCREEN);<br />
HWND hDesktopWnd = ::GetDesktopWindow();<br />
HDC  hDesktopDC = ::GetDC(hDesktopWnd);<br />
HDC  hCaptureDC =:: CreateCompatibleDC(hDesktopDC);<br />
HBITMAP hCaptureBitmap=::CreateCompatibleBitmap(hDesktopDC, nScreenWidth, nScreenHeight);<br />
::SelectObject(hCaptureDC,hCaptureBitmap); <br />
StretchBlt(hCaptureDC,0,0,((nScreenWidth/2)+310),((nScreenHeight/2)+290),hDesktopDC,0,0,nScreenWidth,nScreenHeight,SRCCOPY);<br />
CImage file; <br />
char	str[15];<br />
DWORD filetime=::timeGetTime();<br />
itoa(filetime,str,10);<br />
strcat(str,".png");<br />
char strdrive[25]="C:\\";<br />
strcat(strdrive,str);<br />
file.Attach(hCaptureBitmap);<br />
file.Save(strdrive);<br />

HANDLE hSemaphore = NULL;
LPCTSTR pGlobalName = _T("Global\\MyInstance_938759");

hSemaphore = OpenSemaphore(SEMAPHORE_ALL_ACCESS, FALSE, pGlobalName);
if (!hSemaphore) {
  // it doesn't exists, so create it, to inform another instances
  hSemaphore = CreateSemaphore(NULL, 0, 2, pGlobalName);
} else {
  // another instance already exists; quit!
  return 0;
}