REFERENCE GUIDE

This message is sent prior to the WM_ CREA TE message when a windowis first created.Parameters wParam Contains a handle to the window that is being created.Return valueDefault actionIParamPoints to the CREATESTRUCT data structure for the window.The return value is nonzero if the nonclient area is created. It is zero if anerror occurs; the CreateWindow function will return NULL in this case.Scroll bars are initialized (the scroll-bar position and range are set) and thewindow text is set. Memory used internally to create and maintain thewindow is allocated.This message informs a window that its nonclient area is being destroyed.The DestroyWindow function sends the WM_NCDESTROY message tothe window following the WM_DESTROY message. This message is usedto free the allocated memory block associated with the window.Parameters wParam Is not used.Default actionIParamIs not used.This message frees any memory internally allocated for the window.This message is sent to the window that contains the cursor (or thewindow that used the GetCapture function to capture the mouse input)every time the mouse is moved.Parameters wParam Is not used.Return valueIParam Contains the x- and y-coordinates of the cursor. The x­coordinate is in the low-order word; the y-coordinate is in thehigh-order word. These coordinates are always screencoordinates.The return value of the DefWindowProc function is one of the valuesgiven in Table 6.2, indicating the position of the cursor:672Software development kit