This is xnu-8019. See this file in:
/*
 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1999 Apple Computer, Inc.  All rights reserved.
 *
 * HISTORY
 *
 */

#ifndef __OS_OSMESSAGENOTIFICATION_H
#define __OS_OSMESSAGENOTIFICATION_H

#ifdef __cplusplus
extern "C" {
#endif

#include <mach/mach_types.h>
#include <device/device_types.h>
#include <IOKit/IOReturn.h>

enum {
	kFirstIOKitNotificationType                 = 100,
	kIOServicePublishNotificationType           = 100,
	kIOServiceMatchedNotificationType           = 101,
	kIOServiceTerminatedNotificationType        = 102,
	kIOAsyncCompletionNotificationType          = 150,
	kIOServiceMessageNotificationType           = 160,
	kLastIOKitNotificationType                  = 199,

	// reserved bits
	kIOKitNoticationTypeMask                    = 0x00000FFF,
	kIOKitNoticationTypeSizeAdjShift            = 30,
	kIOKitNoticationMsgSizeMask                 = 3,
};

enum {
	kOSNotificationMessageID            = 53,
	kOSAsyncCompleteMessageID           = 57,
	kMaxAsyncArgs                       = 16
};

enum {
	kIOAsyncReservedIndex       = 0,
	kIOAsyncReservedCount,

	kIOAsyncCalloutFuncIndex    = kIOAsyncReservedCount,
	kIOAsyncCalloutRefconIndex,
	kIOAsyncCalloutCount,

	kIOMatchingCalloutFuncIndex = kIOAsyncReservedCount,
	kIOMatchingCalloutRefconIndex,
	kIOMatchingCalloutCount,

	kIOInterestCalloutFuncIndex = kIOAsyncReservedCount,
	kIOInterestCalloutRefconIndex,
	kIOInterestCalloutServiceIndex,
	kIOInterestCalloutCount
};



// --------------
enum {
	kOSAsyncRef64Count  = 8,
	kOSAsyncRef64Size   = kOSAsyncRef64Count * ((int) sizeof(io_user_reference_t))
};
typedef io_user_reference_t OSAsyncReference64[kOSAsyncRef64Count];

struct OSNotificationHeader64 {
	mach_msg_size_t     size;       /* content size */
	natural_t           type;
	OSAsyncReference64  reference;

#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
	unsigned char       content[];
#else
	unsigned char       content[0];
#endif
};

#pragma pack(4)
struct IOServiceInterestContent64 {
	natural_t           messageType;
	io_user_reference_t messageArgument[1];
};
#pragma pack()
// --------------

#if !KERNEL_USER32

enum {
	kOSAsyncRefCount    = 8,
	kOSAsyncRefSize     = 32
};
typedef natural_t OSAsyncReference[kOSAsyncRefCount] __kernel_ptr_semantics;

struct OSNotificationHeader {
	mach_msg_size_t     size;       /* content size */
	natural_t           type;
	OSAsyncReference    reference;

#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
	unsigned char       content[];
#else
	unsigned char       content[0];
#endif
};

#pragma pack(4)
struct IOServiceInterestContent {
	natural_t   messageType;
	void *      messageArgument[1];
};
#pragma pack()

#endif /* KERNEL_USER32  */

struct IOAsyncCompletionContent {
	IOReturn result;
#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
	void * args[] __attribute__ ((packed));
#else
	void * args[0] __attribute__ ((packed));
#endif
};

#ifndef __cplusplus
typedef struct OSNotificationHeader OSNotificationHeader;
typedef struct IOServiceInterestContent IOServiceInterestContent;
typedef struct IOAsyncCompletionContent IOAsyncCompletionContent;
#endif

#ifdef __cplusplus
}
#endif

#endif /*  __OS_OSMESSAGENOTIFICATION_H */