IEnumFilters::Next method (strmif.h)

Article
07/27/2023

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 Next method retrieves the specified number of filters in the enumeration sequence.

Syntax

HRESULT Next(
  [in]  ULONG       cFilters,
  [out] IBaseFilter **ppFilter,
  [out] ULONG       *pcFetched
);

Parameters

[in] cFilters

Number of filters to retrieve.

[out] ppFilter

Array of size cFilters that is filled with IBaseFilter interface pointers. The caller must release the interfaces.

[out] pcFetched

Receives the number of filters retrieved. Can be NULL if cFilters is 1.

Return value

Value	Description
S_FALSE	Did not retrieve as many filters as requested.
S_OK	Success.
E_INVALIDARG	Invalid argument.
E_POINTER	NULL pointer argument.
VFW_E_ENUM_OUT_OF_SYNC	The graph has changed and is now inconsistent with the enumerator.

Remarks

If the method succeeds, the IBaseFilter pointers all have outstanding reference counts. Be sure to release them when you are done.

If the filter graph changes (for example, the application removes a filter), the enumerator is no longer be consistent with the graph, and the method returns VFW_E_ENUM_OUT_OF_SYNC. Discard any data obtained from previous calls to the enumerator, because it might be invalid. Update the enumerator by calling the IEnumFilters::Reset method. You can then call the Next method safely.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	strmif.h (include Dshow.h)
Library	Strmiids.lib