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

NAME
       makedev, major, minor - manage a device number

SYNOPSIS
       #define BSDSOURCE             /* See featuretestmacros(7) */
       #include 

       devt makedev(int maj, int min);

       unsigned int major(devt dev);
       unsigned int minor(devt dev);

DESCRIPTION
       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 devt.

       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).

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       ┌────────────────────────────┬───────────────┬─────────┐
       │Interface                   │ Attribute     │ Value   │
       ├────────────────────────────┼───────────────┼─────────┤
       │makedev(), major(), minor() │ Thread safety │ MT-Safe │
       └────────────────────────────┴───────────────┴─────────┘
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:  gnudevmakedev(),
       gnudevmajor(), and gnudevminor().  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 3.53 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                             2012-05-10                        MAKEDEV(3)