[tex-live] linking with fontconfig (xetex and xdvipdfmx)

[Frank Küster]

Jonathan Kew <jonathan_kew at sil.org> wrote:

> The numbering here is a bit confusing (to me, at least).
>
> AFAICT, all fontconfig releases (so far) are considered some form of  
> "fontconfig 1", and this is reflected in package names such as  
> "libfontconfig1" seen in some Linux distros.

This is the so-called SONAME (because it's the file
$libdir/libfontconfig.so.1 that is searched for by the dynamic
linker/loader at runtime).  The fact that it is always 1 indicates that
the ABI is backwards-compatible, i.e. any program linked against
fontconfig headers of that SONAME version can be used with
libfontconfig.so.1, as long as the library version is at least the same
as used during linking.

The library version (the 2.2, 2.3 or 2.4) is just a release version
number for the tarball like linux' 2.6.18 or TeXlive's 2005.  Of course,
besides improvements in performance or standard-conformance, new
functions may have been added to the API, therefore you can't use an
older version than the one that provides the symbols you want to use,
and this is where you need to check for at build-time *and* at run time.
It depends on the symbols you use, not on which were available in the
version you build against.

[Rest snipped with approval.]

Regards, Frank
-- 
Frank Küster
Single Molecule Spectroscopy, Protein Folding @ Inst. f. Biochemie, Univ. Zürich
Debian Developer (teTeX/TeXLive)