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Date:   Mon, 30 Jul 2018 19:30:53 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     David Howells <dhowells@redhat.com>
Cc:     viro@zeniv.linux.org.uk, torvalds@linux-foundation.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 36/38] vfs: Add a sample program for the new mount API
 [ver #10]
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On Mon 2018-07-30 16:33:15, David Howells wrote:
> Pavel Machek <pavel@ucw.cz> wrote:
>=20
> > Well, I guess errors should have numbers, and catalog explaining what
> > error means what. That way userspace can translate, and it is what we
> > do with errno.
> >
> > I believe numbers are best. If you hate numbers, you can still use
> > strings, as long as you can enumerate them in docs (but it will be
> > strange design).
>=20
> Simply returning error numbers is *not* sufficient.  The messages need to=
 be
> parameterised.

Still userland needs a way to understand the errors.

One way is to pass ( "not enough pixie dust (%d too short) on device
%s in %s", 123, "foo", "warddrobe" ). But if you pass it as one
string, it becomes hard / impossible to parse. (For example if device
is named "foo in bar".)

									Pavel
--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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