NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       makedev, major, minor - manage a device number

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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).

ATTRIBUTES         top

       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         top

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

NOTES         top

       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.

SEE ALSO         top

       mknod(2), stat(2)

COLOPHON         top

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Linux                            2016-03-15                       MAKEDEV(3)