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Date: Tue, 19 Feb 2019 01:26:15 -0800 (PST)
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Subject: Re: How To Create And Use Memory Map Files
From: Patrick Jakubowski <patrick.jakubowski@googlemail.com>
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Xref: reader01.eternal-september.org comp.lang.ada:55577
Date: 2019-02-19T01:26:15-08:00
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On Monday, 18 February 2019 11:44:33 UTC+1, Niklas Holsti  wrote:
> On 19-02-18 10:19 , Dmitry A. Kazakov wrote:
>=20
> > In more OSes more advanced than Linux one can have shared memory withou=
t
> > any files involved. The memory object could even be anonymous if one
> > process passes a handle to the memory to another.
>=20
> Linux supports the "Unix System V" inter-process communication=20
> mechanisms, including shared memory segments that are not memory-mapped=
=20
> files and can be anonymous in the above sense.
>=20
> See e.g. http://man7.org/linux/man-pages/man7/svipc.7.html

In Linux even memory mapped files are not necessary backed by a file. It ca=
n be just pages of memory even without file descriptor. These mappings are =
called ANONYMOUS and can be both private to a process or shared between pro=
cesses. I did quick look at gnatcoll and that library doesn't support anony=
mous mappings.I would make quick C function call to mmap() or modify GNATCO=
LL.Mmap package.