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KsStreamPointerLock function

The KsStreamPointerLock function attempts to lock the specified stream pointer.

Syntax


NTSTATUS KsStreamPointerLock(
  _In_  PKSSTREAM_POINTER StreamPointer
);

Parameters

StreamPointer [in]

A pointer to a KSSTREAM_POINTER structure representing the stream pointer to attempt to lock.

Return value

KsStreamPointerLock returns either STATUS_SUCCESS, indicating that the stream pointer has been locked, or an appropriate error code. STATUS_DEVICE_NOT_READY is the usual error code indicating that the frame could not be locked. This error code frequently means that the frame to which StreamPointer was pointing was canceled.

Remarks

A locked stream pointer guarantees that there is a data frame associated with the stream pointer and that this frame is not canceled as long as the lock is maintained. The minidriver should lock a stream pointer before attempting to access the data to which the stream pointer points.

If the pin that the stream pointer references specifies that DMA scatter/gather mappings should be generated using KSPIN_FLAG_GENERATE_MAPPINGS, AVStream generates the mappings when the stream pointer is locked.

Also see Stream Pointers.

Requirements

Version

Available in Microsoft Windows XP and later operating systems and DirectX 8.0 and later DirectX versions.

Header

Ks.h (include Ks.h)

Library

Ks.lib

IRQL

<=DISPATCH_LEVEL

See also

KsStreamPointerUnlock

 

 

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