mmap2(2) - phpMan

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 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 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
       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 information about reporting bugs, can be found at http://www.ker-
       nel.org/doc/man-pages/.



Linux                             2008-04-22                          MMAP2(2)

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