Section (2) mmap2
mmap2 — map files or devices into memory
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.
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
a pointer to the mapped area. On error, −1 is returned
errno is set
Problem with getting the data from user space.
(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).
On architectures where this system call is present, the
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.
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Copyright (C) 2002, Michael Kerrisk
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Modified 31 Jan 2002, Michael Kerrisk <mtk.manpagesgmail.com>
Added description of mmap2
Modified, 2004-11-25, mtk -- removed stray #endif in prototype