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From: Florian Weimer <fw@deneb.enyo.de>
Newsgroups: comp.lang.ada
Subject: Re: Exclusive file access
Date: Mon, 07 Sep 2015 20:27:58 +0200
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Date: 2015-09-07T20:27:58+02:00
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* Dmitry A. Kazakov:

> Anything you can encode in Unicode you can encode in Unicode.

This is simply not true across multiple Unicode versions (and when
dealing with multi-byte encodings).  It is not possible to express all
possible UCS-2 sequences in UTF-32, in the sense that converting from
UTF-32 completely covers the entire set of UCS-2 strings.

>> The user may select a file, but the application cannot open it.
>> That's a poor user experience.
>
> That is not a problem at all. You cannot create a 999TB large file either.

Well ...

-rw-r--r-- 1 fw fw 1098412116148224 Sep  7 20:23 t

And I expect that I can delete it, too.  Anything else would be a bug.

> System-specific constraints put on an implementation do not effect the
> interface, which has Name_Error in it already.

It's not a constraint that the system imposes, it's something that
requires careful thought from the programming language implementor.
If they impose stronger constraints on strings than what the file
system enforces, you end up with non-nameable files and a poor user
experience.