On 2021-Jun-18, Boris Kolpackov wrote: > Tom Lane <t...@sss.pgh.pa.us> writes: > > > I think putting a version number as such in there is a truly > > horrid idea. However, I could get behind adding a boolean flag > > that says specifically whether the pipeline feature exists. > > Then you'd do something like > > > > #ifdef LIBPQ_HAS_PIPELINING > > > > rather than embedding knowledge of exactly which release > > added that. > > That would be even better, but I agree with what others have > said: we would have to keep adding such feature test macros > going forward.
But we do not add that many significant features to libpq in the first place, so I'm not sure it would be too bad. As far as I am aware, this is the first time someone has requested a mechanism to detect feature presence specifically in libpq. To put a number to it, I counted the number of commits to exports.txt since Jan 2015 -- there are 17. But many of them are just intra-release fixups; the number of actual "features" is 11, an average of two per year. That seems small enough to me. So I'm +1 on adding this "feature macro". (The so-version major changed from 4 to 5 in commit 1e7bb2da573e, dated April 2006.) > I think ideally you would want to have both since the version > macro could still be helpful in dealing with "features" that you > did not plan to add (aka bugs). > > > > Comparing v13 and v14 libpq-fe.h, I see that there is a solution > > available now: "#ifdef PQ_QUERY_PARAM_MAX_LIMIT". > > Hm, it must have been added recently since I don't see it in 14beta1. > But thanks for the pointer, if nothing better comes up this will > have to do. Yeah, this one was added by commit cb92703384e2 on June 8th, three weeks after beta1. -- Álvaro Herrera Valdivia, Chile "Pido que me den el Nobel por razones humanitarias" (Nicanor Parra)
