IPreFetchOffset interface (portcls.h)
The IPreFetchOffset
interface controls the prefetch offset, which is the number of bytes separating the play and write cursors in a DirectSound output stream. A WavePci miniport driver can use this interface to prevent the prefetch offset from growing too large when the driver allocates a large number of mappings. This interface is supported only in Windows XP and later. To determine whether the WavePci port driver supports the IPreFetchOffset
interface, a miniport driver calls the port stream (IPortWavePciStream) object's QueryInterface method with REFIID IID_IPreFetchOffset.
For more information about the IPreFetchOffset
interface, see Prefetch Offsets.
Inheritance
The IPreFetchOffset interface inherits from the IUnknown interface. IPreFetchOffset also has these types of members:
Methods
The IPreFetchOffset interface has these methods.
IPreFetchOffset::SetPreFetchOffset The SetPreFetchOffset method sets the prefetch offset, which is the number of bytes of data separating the write cursor from the play cursor in a DirectSound output stream. |
Requirements
Requirement | Value |
---|---|
Target Platform | Windows |
Header | portcls.h |