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KSQUERYBUFFER structure (ks.h)

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The KSQUERYBUFFER structure is used when querying for outstanding buffers available on an event with KSEVENT_TYPE_QUERYBUFFER.

Syntax

typedef struct {
  KSEVENT      Event;
  PKSEVENTDATA EventData;
  PVOID        Reserved;
} KSQUERYBUFFER, *PKSQUERYBUFFER;

Members

Event

Specifies the description of the original event, with the KSEVENT_TYPE_QUERYBUFFER flag set instead of the KSEVENT_TYPE_ENABLEBUFFERED flag.

EventData

A pointer to a KSEVENTDATA structure. This is the same pointer supplied to AVStrMiniAddEvent at event enable time. This pointer is used as the unique identifier in locating the event, just as it is used when disabling the event.

Reserved

Not used, and set to zero.

Remarks

If KSEVENT_TYPE_ENABLEBUFFERED was used to enable an event that also buffers data, then the data produced by the event can be queried using this method. The description of the event being queried is provided as the first parameter, and any buffer is provided as the second parameter to the query.

The buffer length needed can be queried by providing a zero length output buffer. The size of buffer is returned in the BytesReturned parameter, with a warning status of STATUS_BUFFER_OVERFLOW.

Alternatively, the query returns one of the following status values:

Return Value Description
STATUS_NOT_FOUND event was not found
STATUS_INVALID_PARAMETER it was not being buffered
STATUS_NO_MORE_ENTRIES no buffers were available
STATUS_BUFFER_TOO_SMALL buffer size was insufficient.
STATUS_SUCCESS life is good.

Requirements

Requirement Value
Header ks.h (include Ks.h)

See also

KSBUFFER_ITEM

KSEVENT