CWindow::IsIconic
Determines whether the window is minimized.
BOOL IsIconic( ) const throw();
See IsIconic in the Windows SDK.
//The following example attaches an HWND to the CWindow object and
//calls CWindow::IsIconic() to determine if the window is minimized
CWindow myWindow;
myWindow.Attach(hWnd);
BOOL bIconic = myWindow.IsIconic();
Header: atlwin.h