[FFmpeg-devel] [PATCH] Enhance ffmpeg.c:opt_default()

Stefano Sabatini stefano.sabatini-lala
Sun Nov 30 22:27:01 CET 2008

On date Sunday 2008-11-30 21:02:43 +0100, Michael Niedermayer encoded:
> On Sun, Nov 30, 2008 at 08:22:35PM +0100, Stefano Sabatini wrote:
> > The current semantics of av_set_string2() is to return NULL if the
> > option hasn't been found *or* if the value wasn't valid, so there is
> > currently no way to distinguish the two cases (which is the reason of
> > the patchset).
> > 
> > I think that if the function *finds* the option but can't set the
> > value because the value isn't valid, it is still a good idea to return
> > the option found, at least it seems better because this way we're
> > providing more information to the invoker.
> the problem iam having with this is when the "user" doesnt care about the
> error message and thus passes NULL.
> At that point he cant find out if the call succeeded

He can always do:
AVOption *o = av_set_string3(..., error, error_size);
if (o && !error)

(yes this way he's forced to pass a non-NULL error...).

On the other hand if he wants to know for whatever reason if the
option was found and doesn't care to know if the value has been set or
not he can do it in just one step.

But I won't insist on this if you prefer the other way.

FFmpeg = Fierce & Funny Mortal Portable Erotic Guru

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