mmap2(2) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       mmap2 - map files or devices into memory

SYNOPSIS         top

       #include <sys/mman.h>    /* Definition of MAP_* and PROT_* constants */
       #include <sys/syscall.h> /* Definition of SYS_* constants */
       #include <unistd.h>

       void *syscall(SYS_mmap2, unsigned long addr, unsigned long length,
                     unsigned long prot, unsigned long flags,
                     unsigned long fd, unsigned long pgoffset);

DESCRIPTION         top

       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         top

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

ERRORS         top

       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         top

       mmap2() is available since Linux 2.3.31.

CONFORMING TO         top

       This system call is Linux-specific.

NOTES         top

       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         top

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

COLOPHON         top

       This page is part of release 5.12 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/.

Linux                          2021-03-22                       MMAP2(2)

Pages that refer to this page: mmap(2)remap_file_pages(2)syscalls(2)