From: Tom Lane <tgl@sss.pgh.pa.us>
To: Sebastien FLAESCH <sf@4js.com>
cc: pgsql-interfaces@lists.postgresql.org
Subject: Re: Type scale returned by PQfmod() 65531 for time/timestamp output
 parameter?
In-reply-to: <91fabdcd-0eb3-c970-a28c-248a6ff8a360@4js.com>
References: <093e1214-7057-f80c-5c3c-74076b7bb555@4js.com>
 <7537.1518711940@sss.pgh.pa.us>
 <f80e250d-b13f-0852-2a11-03218588092f@4js.com>
 <13939.1518794152@sss.pgh.pa.us>
 <91fabdcd-0eb3-c970-a28c-248a6ff8a360@4js.com>
Comments: In-reply-to Sebastien FLAESCH <sf@4js.com>
	message dated "Mon, 19 Feb 2018 12:16:45 +0100"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <7046.1519056383.1@sss.pgh.pa.us>
Date: Mon, 19 Feb 2018 11:06:23 -0500
Message-ID: <7047.1519056383@sss.pgh.pa.us>
Precedence: bulk

Sebastien FLAESCH <sf@4js.com> writes:
> On 02/16/2018 04:15 PM, Tom Lane wrote:
>> You could try running it through the typmodout function for the column's
>> datatype.  I don't offhand know of any built-in types for which that would
>> be a really plausible typmod, though.  Are you sure your client code isn't
>> mistakenly narrowing it to int16 somewhere?

> As I wrote in my initial mail, I do the following:

> #define VARHDRSZ 4
>      int pgfmod = PQfmod(st->pgResult, i);
>      int pgprec = (pgfmod >> 16);
>      int pgscal = ((pgfmod - VARHDRSZ) & 0xffff);
>      int pgleng = (pgfmod - VARHDRSZ);

That might --- I don't recall offhand --- be the right decoding for
the typmod of a column of type NUMERIC.  It's certainly not right
for any other datatype.  Also, you don't seem to be accounting for
the fact that negative typmod always means "no typmod specified".

			regards, tom lane