From:
Peter Eisentraut <peter_e(at)gmx(dot)net>
To:
Gregory Stark <stark(at)enterprisedb(dot)com>
Cc:
"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>,
pgsql-hackers(at)postgresql(dot)org,
"Bruce Momjian" <bruce(at)momjian(dot)us>,
"David Fetter" <david(at)fetter(dot)org>
Subject:
Re: Macros for typtype (was Re: Arrays of Complex Types)
Date:
2007-04-01 10:04:06
Message-ID:
200704011204.07451.peter_e@gmx.net (view raw or flat )
Thread:
2007-03-02 23:40:16 from David Fetter <david(at)fetter(dot)org>
2007-03-02 23:59:50 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-03 00:42:14 from "Andrew Dunstan" <andrew(at)dunslane(dot)net>
2007-03-03 13:14:57 from Martijn van Oosterhout <kleptog(at)svana(dot)org>
2007-03-03 14:06:11 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-03-03 17:25:23 from David Fetter <david(at)fetter(dot)org>
2007-03-03 17:45:32 from Gregory Stark <stark(at)enterprisedb(dot)com>
2007-03-04 00:48:38 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-03-06 21:05:56 from David Fetter <david(at)fetter(dot)org>
2007-03-06 21:14:07 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-06 21:17:41 from David Fetter <david(at)fetter(dot)org>
2007-03-06 21:24:36 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-06 21:27:12 from David Fetter <david(at)fetter(dot)org>
2007-03-26 01:31:58 from David Fetter <david(at)fetter(dot)org>
2007-03-26 02:18:14 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-27 18:08:44 from David Fetter <david(at)fetter(dot)org>
2007-03-27 19:39:04 from David Fetter <david(at)fetter(dot)org>
2007-03-27 21:04:39 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-03-28 07:05:24 from Andrew - Supernews <andrew+nonews(at)supernews(dot)com>
2007-03-28 16:57:38 from David Fetter <david(at)fetter(dot)org>
2007-03-28 17:11:05 from Alvaro Herrera <alvherre(at)commandprompt(dot)com>
2007-03-28 17:33:56 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-03-28 18:48:57 from David Fetter <david(at)fetter(dot)org>
2007-03-28 17:35:54 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-28 19:15:20 from Gregory Stark <stark(at)enterprisedb(dot)com>
2007-03-28 19:24:26 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-28 19:41:07 from David Fetter <david(at)fetter(dot)org>
2007-03-30 20:23:58 from David Fetter <david(at)fetter(dot)org>
2007-03-30 21:08:42 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-31 23:10:08 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-03-31 23:13:20 from Bruce Momjian <bruce(at)momjian(dot)us>
2007-03-31 23:36:21 from David Fetter <david(at)fetter(dot)org>
2007-03-31 23:58:34 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-01 00:22:18 from David Fetter <david(at)fetter(dot)org>
2007-04-01 00:28:54 from Peter Eisentraut <peter_e(at)gmx(dot)net>
2007-04-01 02:31:26 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-01 07:40:09 from Peter Eisentraut <peter_e(at)gmx(dot)net>
2007-04-01 07:50:07 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-01 08:15:29 from Peter Eisentraut <peter_e(at)gmx(dot)net>
2007-04-01 09:36:39 from Gregory Stark <stark(at)enterprisedb(dot)com>
2007-04-01 10:04:06 from Peter Eisentraut <peter_e(at)gmx(dot)net>
2007-04-01 18:31:41 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-01 20:18:57 from Peter Eisentraut <peter_e(at)gmx(dot)net>
2007-04-02 04:11:08 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-02 20:10:05 from David Fetter <david(at)fetter(dot)org>
2007-04-03 00:28:15 from Bruce Momjian <bruce(at)momjian(dot)us>
2007-04-03 02:01:44 from Alvaro Herrera <alvherre(at)commandprompt(dot)com>
2007-04-03 06:10:13 from David Fetter <david(at)fetter(dot)org>
2007-04-03 06:30:07 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-03 13:29:23 from David Fetter <david(at)fetter(dot)org>
2007-04-03 14:20:44 from Bruce Momjian <bruce(at)momjian(dot)us>
2007-04-08 22:47:44 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-04-08 23:08:38 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-08 23:32:22 from David Fetter <david(at)fetter(dot)org>
2007-04-08 23:36:17 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-04-09 00:09:59 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-09 00:35:53 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-04-09 00:41:06 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-09 01:53:46 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-04-09 02:24:23 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-09 14:14:41 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-04-09 14:40:49 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-04-09 16:39:36 from David Fetter <david(at)fetter(dot)org>
2007-04-09 19:57:34 from Martijn van Oosterhout <kleptog(at)svana(dot)org>
2007-04-09 20:07:16 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-04-09 21:12:24 from Martijn van Oosterhout <kleptog(at)svana(dot)org>
2007-05-06 17:33:47 from Andrew Dunstan <andrew(at)dunslane(dot)net>
2007-05-06 17:47:32 from David Fetter <david(at)fetter(dot)org>
2007-05-11 18:27:49 from Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
2007-05-11 20:19:51 from "Merlin Moncure" <mmoncure(at)gmail(dot)com>
Lists:
pgsql-hackers pgsql-patches
Gregory Stark wrote:
> > The width is 4 both for the macro and the enum case. Both
> >
> > #define TYPTYPE_BASE 'b'
> >
> > and
> >
> > enum ... {
> > TYPTYPE_BASE = 'b',
> >
> > effectively generate int constants named TYPTYPE_BASE with decimal
> > value 98. So there are no storage advantages either way.
>
> That's not accurate at all.
How so?
> The macro case gives you a constant you
> can only use to initialize integer variables and members that are
> explicitly declared with some integral type. If we consistently
> declare them "char" then they'll be predictably 1 byte long.
But character constants are actually ints, so when you do what you
describe then the compiler has to generate code to copy a four-byte
integer into a single byte. (Of course that can be optimized away,
probably.)
> The enum case does two things. It defines a syntactic meaning for the
> label, *and* it defines a thing "enum typtype" which can be used to
> define variables and members. If the latter is used then Tom is
> saying the standard doesn't specify what width the variable or member
> will be.
The standard says that enums are the same as ints. So when you assign
an enum label to a char variable, then compiler has to generate code to
copy a four-byte integer into a single byte. (Of course that can be
optimized away, probably.)
The fact that you can also declare variables of the enum type is not
under consideration here.
QED
--
Peter Eisentraut
http://developer.postgresql.org/~petere/
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