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IMFHttpDownloadRequest::QueryHeader method (mfidl.h)

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Invoked by Microsoft Media Foundation to retrieve the values of specified HTTP headers from the response to a previously sent HTTP or HTTPS request. Media Foundation invokes this method only after having successfully invoked the EndReceiveResponse method.

Syntax

HRESULT QueryHeader(
  [in]  LPCWSTR szHeaderName,
  [in]  DWORD   dwIndex,
  [out] LPWSTR  *ppszHeaderValue
);

Parameters

[in] szHeaderName

The name of the HTTP header for which the value is being queried.

[in] dwIndex

The index number of the specified header, for the case where the response contains multiple headers with the same name. A value of 0 indicates that the value of the first header with the specified name is requested, 1 indicates that the second header is requested, and so on.

[out] ppszHeaderValue

Set to the value of the requested header, not including the carriage return or line feed characters. The memory for ppszHeaderValue must be allocated with CoTaskMemAlloc and will be freed by Media Foundation with CoTaskMemFree.

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 returned the value of the specified header with the specified index.
E_OUTOFMEMORY
 There is insufficient memory to complete the operation.
E_POINTER
 The ppszHeaderValue parameter is an invalid pointer.
MF_E_OUT_OF_RANGE
 The dwIndex parameter value is out of range.

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