BOOL IsChild( CWnd* pWnd ) const;
pWnd
Identifies the window to be checked.
Indicates whether the window specified by pWnd is a child window or other direct descendant of CWnd. A child window is the direct descendant of CWnd if the CWnd object is in the chain of parent windows that leads from the original pop-up window to the child window.
Specifies the outcome of the function. The value is TRUE if the window identified by pWnd is a child window of CWnd; otherwise FALSE.
::IsChild