_IRP

Metadatacopy
struct _IRP {
    short Type;/* 0x0  2 */
    unsigned short Size;/* 0x2  2 */
    struct _MDL* MdlAddress;/* 0x4  4 */
    unsigned long Flags;/* 0x8  4 */
    union {
        struct _IRP* MasterIrp;/* 0xc  4 */
        long IrpCount;/* 0xc  4 */
        void* SystemBuffer;/* 0xc  4 */
    } AssociatedIrp;/* 0xc  4 */
    struct _LIST_ENTRY ThreadListEntry;/* 0x10  8 */
    struct _IO_STATUS_BLOCK IoStatus;/* 0x18  8 */
    char RequestorMode;/* 0x20  1 */
    unsigned char PendingReturned;/* 0x21  1 */
    char StackCount;/* 0x22  1 */
    char CurrentLocation;/* 0x23  1 */
    unsigned char Cancel;/* 0x24  1 */
    unsigned char CancelIrql;/* 0x25  1 */
    char ApcEnvironment;/* 0x26  1 */
    unsigned char AllocationFlags;/* 0x27  1 */
    struct _IO_STATUS_BLOCK* UserIosb;/* 0x28  4 */
    struct _KEVENT* UserEvent;/* 0x2c  4 */
    union {
        struct {
            void (*UserApcRoutine)(void*, struct _IO_STATUS_BLOCK*, unsigned long);/* 0x30  4 */
            void* UserApcContext;/* 0x34  4 */
        } AsynchronousParameters;/* 0x30  8 */
        union _LARGE_INTEGER AllocationSize;/* 0x30  8 */
    } Overlay;/* 0x30  8 */
    void (*CancelRoutine)(struct _DEVICE_OBJECT*, struct _IRP*);/* 0x38  4 */
    void* UserBuffer;/* 0x3c  4 */
    /* ── cacheline 1 boundary (64 bytes) ── */
    union {
        struct {
            union {
                struct _KDEVICE_QUEUE_ENTRY DeviceQueueEntry;/* 0x40  16 */
                void* DriverContext[4];/* 0x40  16 */
            };/* 0x40  16 */
            struct _ETHREAD* Thread;/* 0x50  4 */
            char* AuxiliaryBuffer;/* 0x54  4 */
            struct _LIST_ENTRY ListEntry;/* 0x58  8 */
            union {
                struct _IO_STACK_LOCATION* CurrentStackLocation;/* 0x60  4 */
                unsigned long PacketType;/* 0x60  4 */
            };/* 0x60  4 */
            struct _FILE_OBJECT* OriginalFileObject;/* 0x64  4 */
        } Overlay;/* 0x40  40 */
        struct _KAPC Apc;/* 0x40  48 */
        void* CompletionKey;/* 0x40  4 */
    } Tail;/* 0x40  48 */
};
/* source: Windows 2000 RC2 DDK Alpha libcntpr.lib CodeView type records; build 2128 per the DDK's ntverp.h */