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MMAP2(2)                   Linux Programmer's Manual                  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
       The  mmap2()  system call operates in exactly the same way 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  applica-
       tions 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 appropri-
       ately.

ERRORS
       EFAULT Problem with getting the data from userspace.

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

       mmap2() can return any of the same errors as mmap(2).

VERSIONS
       mmap2() is available since Linux 2.3.31.

CONFORMING TO
       This system call is Linux-specific.

NOTES
       Nowadays, the glibc mmap() wrapper function invokes this system call rather than the mmap(2) system call.

       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 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                             2008-04-22                          MMAP2(2)