Re: [Devel] Bad problems due to function renaming

[Owen Taylor]

On Fri, 2003-11-14 at 09:28, Tim Ruehsen wrote:
> Am Donnerstag, 13. November 2003 19:14 schrieb Owen Taylor:
> > On Thu, 2003-11-13 at 09:35, Tim Ruehsen wrote:
> > > Am Donnerstag, 13. November 2003 15:24 schrieb Owen Taylor:
> > > > On Thu, 2003-11-13 at 09:13, Tim Ruehsen wrote:
> >
> > [...]
> >
> > > > > OK. Just to understand it: how comes that there are no compiler
> > > > > errors when compiling pango with freetype 2.1.x includes?
> > > >
> > > > Pango uses different symbols depending on the version of FreeType it's
> > > > being compiled against (there are compatibility #defines)
> > >
> > > Interesting. I just scanned the complete source code of pango 1.0.4 (grep
> > > -i FT_Seek ...) and could not find any reference to that function...
> > > maybe you *are* right. But it is not obvious. Where can I find these
> > > defines?
> >
> > It's a rather complex mess of macros in Pango and in FreeType:
> >
> > pango/opentype/fterrcompat.h:
> >
> > ===
> > /* Compat macros for name changes in FreeType 2.1.0
> >  */
> > #if (FREETYPE_MAJOR == 2) && (FREETYPE_MINOR >= 1)
> > [....]
> > #define FILE_Seek( position ) FT_STREAM_SEEK( position)
> > ===
> 
> Thanks, Owen.
> 
> I assume FT_STREAM_SEEK is a freetype 2.1.x macro like
> #define FT_STREAM_SEEK(position) FT_Stream_Seek(position)
> (I do not have the freetype 2.1.x includes installed - i already downgraded 
> to 
> 2.0.9).
> 
> If my assumption is correct it should possible to create a wrapper function 
> like
> return_type FT_Seek_Stream(args) { return FT_Stream_Seek(args); }
> 
> Maybe the args and/or return type changed from freetype 2.0.0 to 2.1.x, but 
> it 
> it such a problem to implement these wrapper functions in future versions of 
> freetype?

I think what you are missing here is that Pango (intentionally) used 
internal FreeType functions. The FreeType people (intentionally) changed
the internal interfaces. What Dave Turner wants is for people to stop
using the internal interfaces (and he has posted an initial plan for
doing the OpenType stuff in an uncoupled way.) So, I doubt the FreeType
people want to add compatibility wrappers here. And I don't blame them.

Regards,
                                        Owen