makedev, major, minor — manage a device number
||unsigned int maj,|
|unsigned int min
A device ID consists of two parts: a major ID, identifying the class of the device, and a minor ID, identifying a specific instance of a device in that class. A device ID is represented using the type dev_t.
Given major and minor device IDs,
makedev() combines these to produce a
device ID, returned as the function result. This device ID
can be given to mknod(2), for example.
minor() functions perform the converse
task: given a device ID, they return, respectively, the major
and minor components. These macros can be useful to, for
example, decompose the device IDs in the structure returned
For an explanation of the terms used in this section, see attributes(7).
minor() functions are not specified in
POSIX.1, but are present on many other systems.
These interfaces are defined as macros. Since glibc 2.3.3,
they have been aliases for three GNU-specific functions:
gnu_dev_minor(). The latter names are
exported, but the traditional names are more portable.
The BSDs expose the definitions for these macros via
> and glibc also exposes definitions for
these macros from that header file if suitable feature test
macros are defined.
This page is part of release 4.07 of the Linux
man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date. The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein. The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.