Indicates whether the window specified by pWnd is a child window or other direct descendant of CWnd.
Identifies the window to be tested.
Specifies the outcome of the function. The value is nonzero if the window identified by pWnd is a child window of CWnd; otherwise 0.
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.