makedev, major, minor — manage a device number
#define _BSD_SOURCE #include <sys/types.h>
dev_t makedev( |
int maj, |
int min); |
int major( |
dev_t dev); |
int minor( |
dev_t dev); |
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.
The major() and 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
by stat(2).
The makedev() major() and 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_makedev(3), gnu_dev_major(3), and gnu_dev_minor(3). The latter names are exported, but the traditional names are more portable.
This page is part of release 3.24 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
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Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk <mtk.manpagesgmail.com> 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 Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date.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 professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. |