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

[Stefano Sabatini]

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.

Regards.
-- 
FFmpeg = Fundamental and Fascinating Merciful Portentous Enhancing Glue