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MMAP2(2)                      Linux Programmer's Manual                      MMAP2(2)

NAME         top

       mmap2 - map files or devices into memory

SYNOPSIS         top

       #include <sys/mman.h>

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

DESCRIPTION         top

       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 applications that use
       a 32-bit off_t to map large files (up to 2^44 bytes).

RETURN VALUE         top

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

ERRORS         top

       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 system page size.

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

VERSIONS         top

       mmap2() is available since Linux 2.3.31.

CONFORMING TO         top

       This system call is Linux-specific.

NOTES         top

       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         top

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

COLOPHON         top

       This page is part of release 3.32 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be found
       at http://www.kernel.org/doc/man-pages/.

Linux                                 2008-04-22                             MMAP2(2)

HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface

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