Re: need advice on library interface
* Glenn Maynard (g_deb@zewt.org) wrote:
> I suppose you could make the functions always take 64-bit integer types.
> That is, roll your own off64_t type if one doesn't exist, and always take
> that type even if you can't honor it. Then the ABI would only change if
> it, for some reason, can't find a 64-bit integer type on one install and
> can later.
This was my initial idea. The problem is that there is no reasonably
portable 64-bit type that I know of.
> > > Standard types that change based on configuration #defines are a pain;
> > > if a library requires _FILE_OFFSET_BITS to match the setting in
> > > applications, it'll cause problems if an application actually wants it
> > > to be left alone for some reason.
> >
> > It is more than just a pain: it is a violation of the ABI. It also makes
> > it impossible to mix libraries in some cases (like the
> > libsndfile/wxWindows case that I mentioned).
>
> That's why I'm suggesting (always) using _LARGEFILE64_SOURCE instead of
> _FILE_OFFSET_BITS: it doesn't change any interfaces, it just makes
> explicit 64-bit ones available.
AFAICS, _FILE_OFFSET_BITS vs. _LARGEFILE64_SOURCE is rather
inconsequential since it will only affect interaction between libsndfile
and libc. I only care about interaction between client programs and
libsndfile.
Unless you are proposing that libsndfile also recognize these symbols and
treat them the way libc does. I hope we can avoid that path.
Josh
--
Joshua Haberman <joshua@haberman.com>
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