KsStreamPointerLock function (ks.h)

The KsStreamPointerLock function attempts to lock the specified stream pointer.

Syntax

KSDDKAPI NTSTATUS KsStreamPointerLock(
  [in] PKSSTREAM_POINTER StreamPointer
);

Parameters

[in] StreamPointer

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

See also

KsStreamPointerUnlock