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IAsyncReader interface

The IAsyncReader interface performs an asynchronous data request on a filter.

This interface is exposed by output pins that perform asynchronous read operations. The interface is used by the input pin on the downstream filter. Applications do not use this interface. The Async File Source filter exposes this interface on its output pin.

Filter developers: Implement this interface if your output pin delivers data in the form of a byte stream (MEDIATYPE_Stream) and supports the pull model. During the connection process, check whether the downstream pin queries for the IAsyncReader interface. If it does not, your pin should either fail the connection or establish some other transport. (If your pin derives from CBasePin, perform this check in the CBasePin::CheckConnect method.)

For more information about using this interface, see the following topics:

Members

The IAsyncReader interface inherits from the IUnknown interface. IAsyncReader also has these types of members:

Methods

The IAsyncReader interface has these methods.

MethodDescription
BeginFlush

Causes all outstanding reads to return.

EndFlush

Ends the flushing operation.

Length

Retrieves the total length of the stream, and the currently available length.

Request

Queues a request for data.

RequestAllocator

Retrieves the actual allocator to be used.

SyncRead

Performs a synchronized read.

SyncReadAligned

Performs an aligned synchronized read.

WaitForNext

Blocks until the next sample is completed or the time-out occurs.

 

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Strmif.h (include Dshow.h)

Library

Strmiids.lib

 

 

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