typedef struct tMIXERCONTROLDETAILS {
    DWORD           cbStruct;       
    DWORD           dwControlID;    
    DWORD           cChannels;      
    union {
        HWND        hwndOwner;      
        DWORD       cMultipleItems; 
    };
    DWORD           cbDetails;      
    LPVOID          paDetails;      
} MIXERCONTROLDETAILS, *PMIXERCONTROLDETAILS, FAR *LPMIXERCONTROLDETAILS;