CAMThread.CallWorker method

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 CallWorker method signals the thread with a request.

Syntax

DWORD CallWorker(
   DWORD dwParam
);

Parameters

dwParam

Request parameter. The derived class defines the meaning of the parameter.

Return value

Returns a value that is defined by the derived class.

Remarks

The CAMThread::GetRequest and CAMThread::CheckRequest methods retrieve the value of the dwParam parameter. The GetRequest method blocks until CallWorker is called.

This method blocks until the CAMThread::Reply method is called. The return value is the parameter given to Reply.

This method holds the CAMThread::m_AccessLock lock to serialize requests. Therefore, do call this method from the thread itself or from any member function that executes in the context of the thread.

Requirements

See also

CAMThread Class