MAKEDEV(3)                                          Linux Programmer's Manual                                         MAKEDEV(3)



NAME
       makedev, major, minor - manage a device number

SYNOPSIS
       #define _BSD_SOURCE
       #include <sys/types.h>

       dev_t makedev(int maj, int min);

       int major(dev_t dev);
       int minor(dev_t dev);


DESCRIPTION
       A  device  ID  consists of two parts: a major ID, identifying the class of the device, and a minor ID, identifying a spe-
       cific 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).

CONFORMING TO
       The makedev() major() and minor() functions are not specified in POSIX.1, but are present on many other systems.

NOTES
       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.

SEE ALSO
       mknod(2), stat(2)

COLOPHON
       This  page  is  part of release 3.25 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/.



Linux                                                      2008-12-01                                                 MAKEDEV(3)