makedev, major, minor — manage a device number
#include <sys/sysmacros.h>
dev_t
makedev( |
unsigned int maj, |
unsigned int min); |
unsigned int
major( |
dev_t dev); |
unsigned 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).
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
makedev(), major(), minor() |
Thread safety | MT-Safe |
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(), gnu_dev_major(), and gnu_dev_minor(). The latter names are
exported, but the traditional names are more portable.
The BSDs expose the definitions for these macros via
<sys/types/.h> 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
https://www.kernel.org/doc/man−pages/.
|
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