Re: Cannot find a working 64-bit integer type on Illumos

On Tue, Dec 10, 2024 at 3:02 PM Thomas Munro <thomas(dot)munro(at)gmail(dot)com> wrote:
> On Thu, Dec 5, 2024 at 12:16 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Now you already snuck the camel's nose under the
> > tent by including stdint.h there, and maybe these additional headers
> > wouldn't do any further damage.
>
> Even though we fixed the immediate issue (thanks), this comment stayed
> with me. I did that because I didn't want to change any interfaces at
> the same time as the <stdint.h> retrofit, but I agree that it feels a
> bit odd hidden in there, and doesn't appear to conform to
> postgres_ext.h's self-description. Stepping back, and I realise it's
> difficult to answer with certainty, I wonder why anyone would ever
> want to use postgres_ext.h directly for the definition of pg_int64
> *without* being a user of libpq-fe.h. I can't find any references to
> pg_int64 (excluding forks of our code) on github; there are a few
> things like proxies and suchlike that include postgres_ext.h for other
> things, mostly bogusly (they also include libpq-fe.h, or they say they
> want NAMEDATALEN, which isn't there anymore).
>
> We have just three lo_*64() functions using that type and then
> pg_usec_time_t. Seems like a very narrow usage that hasn't spread,
> likely only used to receive arguments, and really quite specific to
> libpq-fe.h and not one of the "fundamental Postgres declarations".
> Maybe we should consider moving #include <stdint.h> into libpq-fe.h?
>
> And if we included <stdint.h> overtly, rather than covertly in
> postgres_ext.h, why would we still want a third name for int64_t? We
> could change the three lo_*64() declarations to use the standard type
> directly, but keep the historical typedef marked deprecated.
>
> > But I don't see a strong argument to
> > change long-standing external APIs any more than we absolutely must.
>
> So perhaps you'll hate that idea then. I wonder if you'll hate it
> more than keeping the #include in postgres_ext.h, hence putting the
> idea forward!

Does anyone else have thoughts about this arguable leftover quirk from
the <stdint.h> refactoring work? In brief, shouldn't libpq-fe.h
include <stdint.h> directly, and use int64_t explicitly, instead of
doing it "secretly" in another header that came about because of
historical namespace pollution concerns, now gone? We require you to
have a 64 bit integer type, we require C99, C99 requires int64_t to be
defined if you have a 64 bit type, and there doesn't seem to be any
reason to want pg_int64 other than to use these large object functions
in libpq-fe.h. The current arrangement feels a bit obfuscated,
leading to the patch in the previous email. Adding Ishii-san who
introduced the three uses of pg_int64 to libpq-fe.h in 461ef73f.