1/* Definitions of macros to access `dev_t' values.
2 Copyright (C) 1996-2018 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#ifndef _BITS_SYSMACROS_H
20#define _BITS_SYSMACROS_H 1
21
22#ifndef _SYS_SYSMACROS_H
23# error "Never include <bits/sysmacros.h> directly; use <sys/sysmacros.h> instead."
24#endif
25
26/* dev_t in glibc is a 64-bit quantity, with 32-bit major and minor numbers.
27 Our default encoding is MMMM Mmmm mmmM MMmm, where M is a hex digit of
28 the major number and m is a hex digit of the minor number. This is
29 downward compatible with legacy systems where dev_t is 16 bits wide,
30 encoded as MMmm. It is also downward compatible with the Linux kernel,
31 which (as of 2016) uses 32-bit dev_t, encoded as mmmM MMmm.
32
33 Systems that use an incompatible encoding for dev_t should override this
34 file in the appropriate sysdeps subdirectory. */
35
36#define __SYSMACROS_DECLARE_MAJOR(DECL_TEMPL) \
37 DECL_TEMPL(unsigned int, major, (__dev_t __dev))
38
39#define __SYSMACROS_DEFINE_MAJOR(DECL_TEMPL) \
40 __SYSMACROS_DECLARE_MAJOR (DECL_TEMPL) \
41 { \
42 unsigned int __major; \
43 __major = ((__dev & (__dev_t) 0x00000000000fff00u) >> 8); \
44 __major |= ((__dev & (__dev_t) 0xfffff00000000000u) >> 32); \
45 return __major; \
46 }
47
48#define __SYSMACROS_DECLARE_MINOR(DECL_TEMPL) \
49 DECL_TEMPL(unsigned int, minor, (__dev_t __dev))
50
51#define __SYSMACROS_DEFINE_MINOR(DECL_TEMPL) \
52 __SYSMACROS_DECLARE_MINOR (DECL_TEMPL) \
53 { \
54 unsigned int __minor; \
55 __minor = ((__dev & (__dev_t) 0x00000000000000ffu) >> 0); \
56 __minor |= ((__dev & (__dev_t) 0x00000ffffff00000u) >> 12); \
57 return __minor; \
58 }
59
60#define __SYSMACROS_DECLARE_MAKEDEV(DECL_TEMPL) \
61 DECL_TEMPL(__dev_t, makedev, (unsigned int __major, unsigned int __minor))
62
63#define __SYSMACROS_DEFINE_MAKEDEV(DECL_TEMPL) \
64 __SYSMACROS_DECLARE_MAKEDEV (DECL_TEMPL) \
65 { \
66 __dev_t __dev; \
67 __dev = (((__dev_t) (__major & 0x00000fffu)) << 8); \
68 __dev |= (((__dev_t) (__major & 0xfffff000u)) << 32); \
69 __dev |= (((__dev_t) (__minor & 0x000000ffu)) << 0); \
70 __dev |= (((__dev_t) (__minor & 0xffffff00u)) << 12); \
71 return __dev; \
72 }
73
74#endif /* bits/sysmacros.h */
75