Re: how to guard deprecated signals

[David Nečas (Yeti) <yeti physics muni cz>]

On Tue, Oct 30, 2007 at 10:23:59PM +0200, Stefan Kost wrote:
> just found a property in gstreamer that is deprecated. Thus I get this from gtk-doc:
> 
> WARNING: GstBaseRTPDepayload::queue-delay is deprecated in the inline comments
>          but no deprecation guards were found around the declaration.
>          (See the --deprecated-guards option for gtkdoc-scan.)
> 
> Now I wonder where one should/could add deprecation guards?
> #ifndef GST_DISABLE_DEPRECATED
> #endif
> 
> gtk-doc expects them in the headers.

The warning is wrong.  First, I think marking deprecated
symbols with preprocessor conditionals in the header files
is a matter of coding style of a particular project and
should not be mandatory.

But more to the point, it is impossible to make something
inaccessible with an #ifdef when it's registered run-time by
the library (which, of course, has a completely different
idea of what is deprecated and what is not than the library
version you compiled the app with, and madness lies in the
direction of run-time deprecation handling as deprecation is
nothing else than a weak form of backward compatibility
breach).

So, for signals and properties, you have to trust the
documentation and not emit such warnings.

Yeti

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