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From: Markus Armbruster <armbru@redhat.com>
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	<14e53dd6-3ce9-70a2-21f8-6110a1bc970d@redhat.com>
Date: Thu, 13 Oct 2016 08:39:42 +0200
In-Reply-To: <14e53dd6-3ce9-70a2-21f8-6110a1bc970d@redhat.com> (Eric Blake's
	message of "Wed, 12 Oct 2016 15:55:45 -0500")
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Subject: Re: [Qemu-devel] error reporting in functions
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To: Eric Blake <eblake@redhat.com>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>, qemu-devel <qemu-devel@nongnu.org>

Eric Blake <eblake@redhat.com> writes:

> On 10/12/2016 10:47 AM, Vladimir Sementsov-Ogievskiy wrote:
>> HI all!
>> 
>> My questions is: what are general recommendations in Qemu for return
>> code, if we have Error **errp?
>> What should I prefer: errp, duplicated by int return code, or void
>> functions with errp?
>
> Markus has already had several threads commenting on this very topic in
> the past.  A lot of code uses void return, but some newer code is using

A recent one:
Message-ID: <87a8ekfenp.fsf@dusky.pond.sub.org>
http://lists.gnu.org/archive/html/qemu-devel/2016-10/msg00435.html

> the past.  A lot of code uses void return, but some newer code is using
> an int return for simplifying the call-sites (and glib prefers the int
> rather than void return, as well).  Markus was playing with a Coccinelle
> script to see how painful a bulk-conversion of the code base would be,
> but it is probably stalled behind more pressing work at the moment.

Correct.

>> void + errp seems good, just to not duplicate things. But it has a
>> disadvantage of necessity of "local_err" and "error_propagate" in caller
>> function, if its behaviour depends on callee function success...