IAsyncReader::WaitForNext

Blocks until the next read requested through IAsyncReader::Request completes or the time-out occurs.

HRESULT WaitForNext(
DWORD dwTimeout,
IMediaSample **ppSample,
DWORD *pdwUser );

Parameters

  • dwTimeout
    [in] Time-out in milliseconds; can be zero or INFINITE.
  • ppSample
    [out] Completed sample.
  • pdwUser
    User context.

Return Values

Returns an HRESULT value that depends on the implementation of the interface. Current DirectShow implementation return values include:

Value Description
VFW_E_TIMEOUT A time-out has expired.
VFW_E_WRONG_STATE The operation could not be performed because the filter is in the wrong state.
E_FAIL Failure.
S_OK Success.

Remarks

Samples may not be returned in order. If there is a read error of any sort, a notification will already have been sent by the source filter, and HRESULT will be an error. If ppSample is not null, a request has been completed with the result code returned.

The pdwUser parameter returns the caller's context DWORD corresponding to the sample returned.

 Last updated on Tuesday, July 13, 2004

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