CMsg.CMsg constructor

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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.]

Constructs a CMsg object.

Syntax

CMsg(
   UINT     u,
   DWORD    dw,
   LPVOID   lp,
   CAMEvent *pEvent
);

Parameters

u

Request code, defined by the client of the thread class and understood by the overridden worker thread function.

dw

Flag parameter to the request code.

lp

Pointer to data required by the worker thread as parameter or return values. This data should not be stack-based, as it will be referenced some time after completing the queuing operation.

pEvent

Pointer to the event object that a worker thread can signal to indicate the completion of the operation.

Remarks

This member function contains a request for a CMsgThread worker thread to act on. All the parameters are passed to the worker thread function as parameters when this message gets processed. The meanings of the parameters are defined by the client function that calls the worker thread and the derived class that supplies the worker thread's execution function.

Requirements