mmap2 - map files or devices into memory


   #include <sys/mman.h>

   void *mmap2(void *addr, size_t length, int prot,
                int flags, int fd, off_t pgoffset);


   This  is  probably  not  the  system  call  that you are interested in;
   instead, see mmap(2), which describes the glibc wrapper  function  that
   invokes this system call.

   The  mmap2() system call provides the same interface as mmap(2), except
   that the final argument specifies the offset into the file in 4096-byte
   units  (instead  of  bytes,  as  is  done  by  mmap(2)).   This enables
   applications that use a 32-bit off_t to map large  files  (up  to  2^44


   On success, mmap2() returns a pointer to the mapped area.  On error, -1
   is returned and errno is set appropriately.


   EFAULT Problem with getting the data from user space.

   EINVAL (Various platforms where the  page  size  is  not  4096  bytes.)
          offset * 4096 is not a multiple of the system page size.

   mmap2() can also return any of the errors described in mmap(2).


   mmap2() is available since Linux 2.3.31.


   This system call is Linux-specific.


   On  architectures  where  this system call is present, the glibc mmap()
   wrapper function invokes this  system  call  rather  than  the  mmap(2)
   system call.

   This system call does not exist on x86-64.

   On  ia64,  the unit for offset is actually the system page size, rather
   than 4096 bytes.


   getpagesize(2), mmap(2), mremap(2), msync(2), shm_open(3)


   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.