[rrd-developers] it exposes too much ...

Tobias Oetiker tobi at oetiker.ch
Mon Jun 9 20:17:00 CEST 2008

Hi Sebastian,

> > So how about this. We export the symbols but do NOT put them in
> > rrd.h. this means that if someone wants to code, using them, it
> > will work, but it will also mean that they have to use our private
> > headers for compilation, makeing it clear that there is not
> > guarantee for support in future versions ...
> Frankly, I don't like that at all. I'd rather have some documented and
> correctly handled (SONAME version bump) changes than having to track
> that myself.
> I think, the signature of the exported functions is quite stable, so
> there should not be anything to worry about. Currently, none of the
> file-format specifications (i.e. rrd_format.h) is officially available
> to the user, so I don't think that we will run into any real backward-
> compatibility issues caused by the set of currently exported symbols.

well the trouble is, that the only way to access the contents of
the files is that you have to have access to rrd_t which is defined
in rrd_format.h and this pulls in all of that as well, and since I
intend to change the format to become platform indepenant, with
built in support for the old format, the low level access functions
I imagine would use an opaque handle (rrd_handle_t) which is
returned from rrd_open and can then be used to use all the accessor
functions for the rrd file to mess with it.

This will be for 1.4 and so exporting stuff in this direction now,
while there are no accessor functions nor an opaque data type is
not an ideal move, since it might prompt some users to start using
the lowlevel access functions befor they are properly available and
then come whining when things break with 1.4s proper accessor
functions ...


> So, imho the real concern in that respect is the set of officially
> available data-type definitions and I think that we're currently hiding
> all parts which should cause any trouble.
> Cheers,
> Sebastian

Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten
http://it.oetiker.ch tobi at oetiker.ch ++41 62 213 9902

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