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.kernel.org/doc/man-pages/.