]>
Commit | Line | Data |
---|---|---|
47a0131a MK |
1 | .\" Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk |
2 | .\" <mtk.manpages@gmail.com> | |
3 | .\" | |
93015253 | 4 | .\" %%%LICENSE_START(VERBATIM) |
47a0131a MK |
5 | .\" Permission is granted to make and distribute verbatim copies of this |
6 | .\" manual provided the copyright notice and this permission notice are | |
7 | .\" preserved on all copies. | |
8 | .\" | |
9 | .\" Permission is granted to copy and distribute modified versions of this | |
10 | .\" manual under the conditions for verbatim copying, provided that the | |
11 | .\" entire resulting derived work is distributed under the terms of a | |
12 | .\" permission notice identical to this one. | |
13 | .\" | |
14 | .\" Since the Linux kernel and libraries are constantly changing, this | |
15 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
16 | .\" responsibility for errors or omissions, or for damages resulting from | |
17 | .\" the use of the information contained herein. The author(s) may not | |
18 | .\" have taken the same level of care in the production of this manual, | |
19 | .\" which is licensed free of charge, as they might when working | |
20 | .\" professionally. | |
21 | .\" | |
22 | .\" Formatted or processed versions of this manual, if unaccompanied by | |
23 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 24 | .\" %%%LICENSE_END |
47a0131a | 25 | .\" |
09b8afdc | 26 | .TH MAKEDEV 3 2018-04-30 "Linux" "Linux Programmer's Manual" |
47a0131a MK |
27 | .SH NAME |
28 | makedev, major, minor \- manage a device number | |
29 | .SH SYNOPSIS | |
30 | .nf | |
3350a864 | 31 | .B #include <sys/sysmacros.h> |
dbfe9c70 | 32 | .PP |
eb696b73 | 33 | .BI "dev_t makedev(unsigned int " maj ", unsigned int " min ); |
dbfe9c70 | 34 | .PP |
2540aee7 MK |
35 | .BI "unsigned int major(dev_t " dev ); |
36 | .BI "unsigned int minor(dev_t " dev ); | |
47a0131a | 37 | .fi |
47a0131a MK |
38 | .SH DESCRIPTION |
39 | A device ID consists of two parts: | |
40 | a major ID, identifying the class of the device, | |
41 | and a minor ID, identifying a specific instance of a device in that class. | |
42 | A device ID is represented using the type | |
43 | .IR dev_t . | |
847e0d88 | 44 | .PP |
47a0131a MK |
45 | Given major and minor device IDs, |
46 | .BR makedev () | |
47 | combines these to produce a device ID, returned as the function result. | |
48 | This device ID can be given to | |
49 | .BR mknod (2), | |
50 | for example. | |
847e0d88 | 51 | .PP |
47a0131a MK |
52 | The |
53 | .BR major () | |
54 | and | |
55 | .BR minor () | |
56 | functions perform the converse task: given a device ID, | |
57 | they return, respectively, the major and minor components. | |
58 | These macros can be useful to, for example, | |
59 | decompose the device IDs in the structure returned by | |
60 | .BR stat (2). | |
fce328e6 PH |
61 | .SH ATTRIBUTES |
62 | For an explanation of the terms used in this section, see | |
63 | .BR attributes (7). | |
64 | .TS | |
65 | allbox; | |
66 | lbw27 lb lb | |
67 | l l l. | |
68 | Interface Attribute Value | |
69 | T{ | |
70 | .BR makedev (), | |
71 | .BR major (), | |
72 | .BR minor () | |
73 | T} Thread safety MT-Safe | |
74 | .TE | |
47297adb | 75 | .SH CONFORMING TO |
47a0131a | 76 | The |
9afb166c MK |
77 | .BR makedev (), |
78 | .BR major (), | |
47a0131a MK |
79 | and |
80 | .BR minor () | |
81 | functions are not specified in POSIX.1, | |
82 | but are present on many other systems. | |
3350a864 MF |
83 | .\" The BSDs, HP-UX, Solaris, AIX, Irix. |
84 | .\" The header location is inconsistent: | |
85 | .\" Could be sys/mkdev.h, sys/sysmacros.h, or sys/types.h. | |
47a0131a MK |
86 | .SH NOTES |
87 | These interfaces are defined as macros. | |
88 | Since glibc 2.3.3, | |
89 | they have been aliases for three GNU-specific functions: | |
27d47e71 MK |
90 | .BR gnu_dev_makedev (), |
91 | .BR gnu_dev_major (), | |
47a0131a | 92 | and |
27d47e71 | 93 | .BR gnu_dev_minor (). |
47a0131a | 94 | The latter names are exported, but the traditional names are more portable. |
847e0d88 | 95 | .PP |
85a40055 | 96 | The BSDs expose the definitions for these macros via |
1e50980d | 97 | .IR <sys/types.h> . |
517b7ac4 | 98 | Depending on the version, |
1e50980d | 99 | glibc also exposes definitions for these macros from that |
517b7ac4 MK |
100 | header file if suitable feature test macros are defined. |
101 | However, this behavior was deprecated in glibc 2.25, | |
d2414cb5 | 102 | .\" glibc commit dbab6577c6684c62bd2521c1c29dc25c3cac966f |
a706f0e0 | 103 | and since glibc 2.28, |
517b7ac4 MK |
104 | .\" glibc commit e16deca62e16f645213dffd4ecd1153c37765f17 |
105 | .IR <sys/types.h> | |
106 | no longer provides these definitions. | |
47297adb | 107 | .SH SEE ALSO |
47a0131a MK |
108 | .BR mknod (2), |
109 | .BR stat (2) |