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mmap2(2)


NAME

   mmap2 - map files or devices into memory

SYNOPSIS

   #include <sys/mman.h>

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

DESCRIPTION

   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
   bytes).

RETURN VALUE

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

ERRORS

   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).

VERSIONS

   mmap2() is available since Linux 2.3.31.

CONFORMING TO

   This system call is Linux-specific.

NOTES

   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.

SEE ALSO

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

COLOPHON

   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
   https://www.kernel.org/doc/man-pages/.



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