[FFmpeg-devel] [RFC] The meaning of AVERROR_NOTSUPP

[Howard Chu]

Stefano Sabatini wrote:
> On date Thursday 2010-04-22 09:37:14 +0200, Michael Niedermayer encoded:
>> On Sun, Apr 18, 2010 at 09:27:25PM +0200, Stefano Sabatini wrote:
>>> On date Wednesday 2010-04-14 01:58:41 +0200, Stefano Sabatini encoded:
>>>> On date Saturday 2010-04-03 13:31:29 +0200, Stefano Sabatini encoded:
>>>>> On date Saturday 2010-04-03 12:36:01 +0200, Michael Niedermayer encoded:
>>>> [...]
>>>>>> Feature not implemented
>>>>>> and
>>>>>> Implementing this feature is welcome
>>>>>>
>>>>>> are 2 seperate things
>>>>>>
>>>>>> similarly
>>>>>>
>>>>>> "not implementable"
>>>>>> "requested operation nonsensical"
>>>>>> "we dont want this implemented"
>>>>>> "disabled at compile time, rerun configure"
>>>>>>
>>>>>> are all semantically different
>>>>>>
>>>>>> also you cannot redefine the POSIX error codes to mean something else than
>>>>>> they mean.
>>>>>
>>>>> So taking into account the considerations of Howard and yours, it
>>>>> seems that we can agree on simply dropping AVERROR_NOTSUPP and use
>>>>> AVERROR(ENOSYS) instead.
>>>>>
>>>>> We'll use AVERROR_PATCHWELCOME when a feature is not implemented and
>>>>> we want and can implement it, and we'll use AVERROR(ENOSYS) in all the
>>>>> other cases (feature non-implementable, requested operation
>>>>> nonsensical, feature implementable but we don't want to implement it,
>>>>> feature disabled at compile time etc...).
>>>> [...]
>>>>
>>>> Ping.
>>>
>>> Patch updated.
>>> --
>>> FFmpeg = Funny and Fantastic Mean Peaceful Elitist God
>>
>>>   error.c |    1 -
>>>   error.h |    2 +-
>>>   2 files changed, 1 insertion(+), 2 deletions(-)
>>> a8e541223573b93b115ed0187b4a1e89423cc709  0003-Drop-AVERROR_NOTSUPP-at-the-next-major-bump-use-AVER.patch
>>> > From 2d584bc35ed9cb9e737181b0adf3edc6db6634f1 Mon Sep 17 00:00:00 2001
>>> From: Stefano Sabatini<stefano.sabatini-lala at poste.it>
>>> Date: Fri, 2 Apr 2010 15:11:03 +0200
>>> Subject: [PATCH 3/4] Drop AVERROR_NOTSUPP at the next major bump, use AVERROR(ENOSYS)
>>>   instead which is semantically equivalent.
>>>
>>> ---
>>>   libavutil/error.c |    1 -
>>>   libavutil/error.h |    2 +-
>>>   2 files changed, 1 insertions(+), 2 deletions(-)
>>
>> if people prefer it that way iam ok with it
>
> So people please speak for or against this. AVERROR_NOTSUPP is
> currently never used and from the past discussion seems we have to use
> AVERROR(ENOSYS) instead, so it looks to me only a source of confusion.

Anything that cuts down on confusion must be a good thing...

-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
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