MMAP2(2) Linux Programmer's Manual MMAP2(2)
mmap2 - map files or devices into memory
void *mmap2(void *addr, size_t length, int prot,
int flags, int fd, off_t pgoffset);
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
On success, mmap2() returns a pointer to the mapped area. On error -1
is returned and errno is set appropriately.
EFAULT Problem with getting the data from userspace.
EINVAL (Various platforms where the page size is not 4096 bytes.) off-
set * 4096 is not a multiple of the system page size.
mmap2() can return any of the same errors as mmap(2).
mmap2() is available since Linux 2.3.31.
This system call is Linux-specific.
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.
getpagesize(2), mmap(2), mremap(2), msync(2), shm_open(3)
This page is part of release 3.05 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)