Re: [HACKERS] how solve diff of API counstruct_md_array between

I have developed a patch which creates a new pg_config.h define called
PG_VERSION_NUM, which is a number like 80200, with no beta/devel
designation. I think this will be helpful (eventually) for people
writing plug-ins. Attached.

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Martijn van Oosterhout wrote:
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> On Fri, Feb 24, 2006 at 02:57:19PM -0500, Bruce Momjian wrote:
> > Yea, that is probably the best you can do currently, but it is pretty
> > ugly. We have PQserverVersion() in libpq for use by clients, which
> > does:
> >
> > conn->sversion = (100 * vmaj + vmin) * 100 + vrev;
> >
> > Perhaps we should have a function in the server that has this.
> > PG_VERSION isn't easy to use because it is a string, and changes during
> > minor versions.
>
> We don't need a function to do it, because none of that can be used by
> a compiler. If a structure gains or loses a member, the only way you
> can do it portibly is if the compiler can determine which version to
> use. The only thing the preprocessor can use is:
>
> - Is a (preprocessor) symbol defined
> - Is it numerically greater equal or less than another number
>
> So the only solution would be something like:
>
> #define POSTGRESQL_MAJOR 8
> #define POSTGRESQL_MINOR 1
> #define POSTGRESQL_RELEASE 1
>
> Or
>
> #define POSTGRESQL_VERSION 80101
>
> Maybe something to indicate beta or CVS. Anything else is not likely to
> be an improvement on what we have now. Besides, adding stuff now is not
> terribly useful since people want to support back to 7.3/7.4 and until
> a new scheme is old enough that 8.2 is ancient (first release it could
> possibly appear in) it won't get a lot of usage.
>
> Have a nice day,
> --
> Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> > tool for doing 5% of the work and then sitting around waiting for someone
> > else to do the other 95% so you can sue them.
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--
Bruce Momjian http://candle.pha.pa.us
SRA OSS, Inc. http://www.sraoss.com

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