IPreFetchOffset interface

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.

Methods

The IPreFetchOffset interface has these methods.

Method Description
portcls.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.

Remarks

Requirements

   
Target Platform Windows
Header portcls.h