1 | /* * Copyright (c) 2018 Apple Inc. All rights reserved. |
2 | * |
3 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
4 | * |
5 | * This file contains Original Code and/or Modifications of Original Code |
6 | * as defined in and that are subject to the Apple Public Source License |
7 | * Version 2.0 (the 'License'). You may not use this file except in |
8 | * compliance with the License. The rights granted to you under the License |
9 | * may not be used to create, or enable the creation or redistribution of, |
10 | * unlawful or unlicensed copies of an Apple operating system, or to |
11 | * circumvent, violate, or enable the circumvention or violation of, any |
12 | * terms of an Apple operating system software license agreement. |
13 | * |
14 | * Please obtain a copy of the License at |
15 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
16 | * |
17 | * The Original Code and all software distributed under the License are |
18 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
19 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
20 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
21 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
22 | * Please see the License for the specific language governing rights and |
23 | * limitations under the License. |
24 | * |
25 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
26 | */ |
27 | |
28 | #ifndef _OS_PTRTOOLS_H |
29 | #define _OS_PTRTOOLS_H |
30 | |
31 | /* dereference unaligned pointer 'p' */ |
32 | #define os_unaligned_deref(p) ((__os_unaligned_type(p))(p))->val |
33 | |
34 | /* ensure the compiler emits at most one access to 'val' */ |
35 | #define os_access_once(val) (*((volatile __typeof__((val)) *)&(val))) |
36 | |
37 | #define __os_unaligned_type(p) struct { __typeof__(*(p)) val; } __attribute__((packed)) * |
38 | |
39 | #endif /* _OS_PTRTOOLS_H */ |
40 | |