CBaseWindow.PossiblyEatMessage method

Article
07/27/2023

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The PossiblyEatMessage method enables a derived class to forward messages to another window.

Syntax

virtual BOOL PossiblyEatMessage(
   UINT   uMsg,
   WPARAM wParam,
   LPARAM lParam
);

Parameters

uMsg: Message identifier.
wParam: First message parameter.
lParam: Second message parameter.

Return value

Returns TRUE if the message was forwarded, or FALSE otherwise. The base class returns FALSE.

Remarks

Before the CBaseWindow::OnReceiveMessage method handles a message, it calls PossiblyEatMessage. If PossiblyEatMessage returns TRUE, OnReceiveMessage ignores the message. A derived class can override PossiblyEatMessage so that it forwards some messages to an owner window. For example, the CBaseControlWindow class, which derives from CBaseWindow, forwards keyboard and mouse messages.

Requirements

Requirement	Value
Header	Winutil.h (include Streams.h)
Library	Strmbase.lib (retail builds); Strmbasd.lib (debug builds)

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