IMFHttpDownloadRequest::BeginReadPayload method (mfidl.h)

Invoked by Microsoft Media Foundation to receive the message body of the response to a previously sent HTTP or HTTPS request. Media Foundation invokes this method only after having successfully invoked the EndReceiveResponse method. Since the size of the message body may be large, or unknown, Media Foundation may invoke this method multiple times to retrieve the message body in piecemeal fashion.

Syntax

HRESULT BeginReadPayload(
  [out] BYTE             *pb,
  [in]  ULONG            cb,
  [in]  IMFAsyncCallback *pCallback,
        IUnknown         *punkState
);

Parameters

[out] pb

Pointer to a buffer that receives the data.

[in] cb

Specifies the size of the pb buffer, in bytes.

[in] pCallback

Pointer to the IMFAsyncCallback interface of a callback object that is implemented by Microsoft Media Foundation.

punkState

Pointer to the IUnknown interface of a state object, defined by Microsoft Media Foundation. This parameter can be NULL.

Return value

The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Return code	Description
S_OK	Successfully started the asynchronous operation.

Remarks

Microsoft Media Foundation never invokes BeginReadPayload while a previous call to BeginReadPayload has not yet completed.

Requirements

Requirement	Value
Minimum supported client	Windows 10, version 1703 [desktop apps only]
Minimum supported server	None supported
Target Platform	Windows
Header	mfidl.h
Library	Mfplat.lib; Mfplat.dll

See also

IMFHttpDownloadRequest