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

   │InterfaceAttributeValue   │
   │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.


   mknod(2), stat(2)


   This  page  is  part of release 4.09 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


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.