Re: libpq version macro to use or not PQsocketPoll

Dominique Devienne <ddevienne@gmail.com> writes:
> Hi. Now that v17beta2 is part of my dev-env, I'm trying out the new API.
> And I discover there's no version macro for conditional compilation in LIBPQ...

Indeed, that's an oversight, and there's a number of other things
we added to libpq-fe.h between 16 and 17 that probably deserve
their own LIBPQ_HAS symbols.

> I'm not sure what's so wrong with version macro as such.

A couple of things:
* It doesn't help if we forget to update it, so it's not really
  better than HAS_ symbols on that score.
* Usage is error-prone (you might test for the wrong cutoff version)
  and not very readable.
* We can't retroactively make such a symbol appear in old copies
  of libpq-fe.h.

            regards, tom lane