typedef struct _ALPC_COMPLETION_LIST_STATE
{
    union
    {
        struct
        {
            volatile unsigned __int64 Head : 24;
            volatile unsigned __int64 Tail : 24;
            volatile unsigned __int64 ActiveThreadCount : 16;
        } s1;
        volatile unsigned __int64 Value;
    } u1;
} ALPC_COMPLETION_LIST_STATE, *PALPC_COMPLETION_LIST_STATE;