From: Eli Zaretskii <eliz@gnu.org>
To: Po Lu <luangruo@yahoo.com>
Cc: emacs-devel@gnu.org, stefankangas@gmail.com
Subject: Re: master 37889523278: Add new `swap` macro and use it
Date: Sat, 06 Jan 2024 10:44:02 +0200 [thread overview]
Message-ID: <83o7dyua0d.fsf@gnu.org> (raw)
In-Reply-To: <87plye9ahs.fsf@yahoo.com> (message from Po Lu on Sat, 06 Jan 2024 15:39:11 +0800)
> From: Po Lu <luangruo@yahoo.com>
> Cc: Stefan Kangas <stefankangas@gmail.com>
> Date: Sat, 06 Jan 2024 15:39:11 +0800
>
> Stefan Kangas <stefankangas@gmail.com> writes:
>
> > branch: master
> > commit 37889523278fe65733938fb11c3701898309961c
> > Author: Stefan Kangas <stefankangas@gmail.com>
> > Commit: Stefan Kangas <stefankangas@gmail.com>
> >
> > Add new `swap` macro and use it
> >
> > A `swap` macro prevents programming errors and is more concise.
> > It is a natural addition to our existing `min` and `max` macros.
>
> It's well known that a generic "swap" macro is impossible to express in
> Standard C for lack of a standard "typeof"-like expression. To
> compensate for this limitation, the macro must accept an argument
> identifying the type of the field where the temporary value is saved,
> which is more trouble than it's worth and reintroduces the type
> conversion problems such macros are intended to prevent.
>
> Neither typeof nor __typeof__ are portable by our standards, the latter
> being an extension compatible with the Standard enabled when GCC is
> configured to obey the standard to the letter, while the former is a
> keyword enabled in other situations.
Regardless of portability issues, I think the macro should be called
SWAP, upper-case, to avoid clashes with functions.
next prev parent reply other threads:[~2024-01-06 8:44 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <170452579053.27998.16123231327386305897@vcs2.savannah.gnu.org>
[not found] ` <20240106072311.28B8FC0034E@vcs2.savannah.gnu.org>
2024-01-06 7:39 ` master 37889523278: Add new `swap` macro and use it Po Lu
2024-01-06 8:44 ` Eli Zaretskii [this message]
2024-01-06 8:45 ` Po Lu
2024-01-06 9:18 ` Stefan Kangas
2024-01-06 10:33 ` Po Lu
2024-01-06 11:30 ` Stefan Kangas
2024-01-06 13:13 ` Po Lu
2024-01-06 13:59 ` Eli Zaretskii
2024-01-06 14:41 ` Po Lu
2024-01-06 15:34 ` Eli Zaretskii
2024-01-07 1:39 ` Po Lu
2024-01-07 6:34 ` Stefan Kangas
2024-01-07 7:50 ` Po Lu
2024-01-07 8:33 ` Eli Zaretskii
2024-01-07 9:45 ` Stefan Kangas
2024-01-07 10:36 ` Po Lu
2024-01-07 11:34 ` Eli Zaretskii
2024-01-07 11:53 ` Po Lu
2024-01-07 14:37 ` Eli Zaretskii
2024-01-07 17:32 ` Stefan Kangas
2024-01-08 2:15 ` Po Lu
2024-01-07 7:09 ` Eli Zaretskii
2024-01-12 0:50 ` Gregory Heytings
2024-01-13 10:16 ` Stefan Kangas
2024-01-14 3:03 ` Richard Stallman
2024-01-14 5:14 ` Po Lu
2024-01-14 7:07 ` Eli Zaretskii
2024-01-14 8:05 ` Po Lu
2024-01-14 9:31 ` Eli Zaretskii
2024-01-15 1:32 ` Gregory Heytings
2024-01-15 12:41 ` Eli Zaretskii
2024-01-15 13:56 ` Po Lu
2024-01-15 14:13 ` Eli Zaretskii
2024-01-18 1:01 ` Gregory Heytings
2024-01-18 2:11 ` Po Lu
2024-01-27 1:26 ` Gregory Heytings
2024-01-27 2:58 ` Po Lu
2024-01-27 23:44 ` Stefan Kangas
2024-01-28 1:51 ` Po Lu
2024-01-28 2:35 ` Stefan Kangas
2024-01-28 4:17 ` Po Lu
2024-01-28 6:28 ` Eli Zaretskii
2024-01-28 2:22 ` Gregory Heytings
2024-01-28 4:03 ` Po Lu
2024-01-30 2:00 ` Gregory Heytings
2024-01-30 2:41 ` Po Lu
2024-01-28 6:40 ` Eli Zaretskii
2024-01-30 1:59 ` Gregory Heytings
2024-01-30 12:41 ` Eli Zaretskii
2024-01-18 6:22 ` Eli Zaretskii
2024-01-27 1:25 ` Gregory Heytings
2024-01-27 3:08 ` Po Lu
2024-01-27 7:19 ` Eli Zaretskii
2024-01-17 3:29 ` Richard Stallman
2024-01-17 10:16 ` Stefan Kangas
2024-01-17 11:15 ` Po Lu
2024-01-17 21:15 ` Stefan Kangas
2024-01-18 0:39 ` Po Lu
2024-01-18 19:17 ` Stefan Kangas
2024-01-19 1:10 ` Po Lu
2024-01-20 20:31 ` Stefan Kangas
2024-01-22 3:35 ` Richard Stallman
2024-01-22 4:48 ` Po Lu
2024-01-22 18:21 ` Dmitry Gutov
2024-01-23 0:50 ` Po Lu
2024-01-25 23:38 ` Stefan Kangas
2024-01-26 2:02 ` Po Lu
2024-01-26 7:53 ` Eli Zaretskii
2024-01-26 7:38 ` Eli Zaretskii
2024-01-19 3:32 ` Richard Stallman
2024-01-19 4:12 ` Po Lu
2024-01-27 1:27 ` Gregory Heytings
2024-01-27 23:56 ` Stefan Kangas
2024-01-28 2:23 ` Gregory Heytings
2024-01-13 8:02 ` Stefan Kangas
2024-01-13 9:14 ` Eli Zaretskii
2024-01-13 9:50 ` Mattias Engdegård
2024-01-06 8:50 ` Stefan Kangas
2024-01-06 9:09 ` Po Lu
2024-01-06 9:52 ` Andreas Schwab
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