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mmap2(2) [minix man page]

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

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) sys- tem 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 4.15 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 Linux 2017-09-15 MMAP2(2)

Check Out this Related Man Page

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

remap_file_pages - create a nonlinear file mapping SYNOPSIS
#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <sys/mman.h> int remap_file_pages(void *addr, size_t size, int prot, ssize_t pgoff, int flags); DESCRIPTION
The remap_file_pages() system call is used to create a nonlinear mapping, that is, a mapping in which the pages of the file are mapped into a nonsequential order in memory. The advantage of using remap_file_pages() over using repeated calls to mmap(2) is that the former approach does not require the kernel to create additional VMA (Virtual Memory Area) data structures. To create a nonlinear mapping we perform the following steps: 1. Use mmap(2) to create a mapping (which is initially linear). This mapping must be created with the MAP_SHARED flag. 2. Use one or more calls to remap_file_pages() to rearrange the correspondence between the pages of the mapping and the pages of the file. It is possible to map the same page of a file into multiple locations within the mapped region. The pgoff and size arguments specify the region of the file that is to be relocated within the mapping: pgoff is a file offset in units of the system page size; size is the length of the region in bytes. The addr argument serves two purposes. First, it identifies the mapping whose pages we want to rearrange. Thus, addr must be an address that falls within a region previously mapped by a call to mmap(2). Second, addr specifies the address at which the file pages identified by pgoff and size will be placed. The values specified in addr and size should be multiples of the system page size. If they are not, then the kernel rounds both values down to the nearest multiple of the page size. The prot argument must be specified as 0. The flags argument has the same meaning as for mmap(2), but all flags other than MAP_NONBLOCK are ignored. RETURN VALUE
On success, remap_file_pages() returns 0. On error, -1 is returned, and errno is set appropriately. ERRORS
EINVAL addr does not refer to a valid mapping created with the MAP_SHARED flag. EINVAL addr, size, prot, or pgoff is invalid. VERSIONS
The remap_file_pages() system call appeared in Linux 2.5.46; glibc support was added in version 2.3.3. CONFORMING TO
The remap_file_pages() system call is Linux-specific. SEE ALSO
getpagesize(2), mmap(2), mmap2(2), mprotect(2), mremap(2), msync(2) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at Linux 2008-04-22 REMAP_FILE_PAGES(2)
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