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       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.


       mknod(2), stat(2)


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