typedef struct _MIXER_DATA_ITEM { LIST_ENTRY Entry; LARGE_INTEGER LastSet; USHORT Message; USHORT Id; } MIXER_DATA_ITEM, *PMIXER_DATA_ITEM;
The MIXER_DATA_ITEM structure, defined in mixer.h, is used to represent a data item for either a mixer line or a mixer control. The structure is initialized by calling SoundInitDataItem and is modified by SoundMixerChangedItem.
Drivers allocate one of these structures for each line and control that can change. The structure must be globally allocated, because soundlib.lib does not copy it. Instead, soundlib.lib modifies the structure’s Entry element to determine the structure’s location within a linked list.