From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Jonathan Wakely <jwakely@redhat.com>
Cc: Florian Weimer <fweimer@redhat.com>,
Rich Felker <dalias@libc.org>,
Paul Pluzhnikov via Libc-alpha <libc-alpha@sourceware.org>,
Paul Pluzhnikov <ppluzhnikov@google.com>
Subject: Re: [patch] Use __builtin_FILE and __builtin_LINE in assert implementation in C++
Date: Tue, 24 Jan 2023 15:07:39 +0000 [thread overview]
Message-ID: <Y8/0O3XmWK+GJkCG@arm.com> (raw)
In-Reply-To: <CACb0b4nCx6MT+LSzMDo-k-9FODd3efb0YZ+YH7+UroJYp5bCxg@mail.gmail.com>
The 01/24/2023 12:17, Jonathan Wakely via Libc-alpha wrote:
> On Tue, 24 Jan 2023 at 12:08, Florian Weimer <fweimer@redhat.com> wrote:
> > There's also the issue that <cassert> is defined in terms of ISO C,
> > and ISO C specifies that __FILE__ and __LINE__ must be used. Is that
> > another defect? But maybe the difference is not observable because
> > __FILE__ cannot be redefined?
>
> I don't think it's observable. C requires the text printed by a failed
> assert to include "the values of the preprocessing macros __FILE__ and
> __LINE__ " but it doesn't require the actual tokens to appear in the
> definition. The built-ins do return "the values" of those macros, so
> that seems OK to me.
is that a real fix? the token sequence is the same in different
TUs with the builtins but the actual printed path is different,
so if the linker picks a definition at random then the produced
binary is not deterministic.
why is this better than just using __FILE__?
next prev parent reply other threads:[~2023-01-24 15:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-17 19:28 Paul Pluzhnikov
2023-01-23 14:26 ` Florian Weimer
2023-01-24 11:10 ` Rich Felker
2023-01-24 11:19 ` Rich Felker
2023-01-24 11:19 ` Florian Weimer
2023-01-24 11:23 ` Rich Felker
2023-01-24 11:53 ` Jonathan Wakely
2023-01-24 12:08 ` Florian Weimer
2023-01-24 12:17 ` Jonathan Wakely
2023-01-24 15:07 ` Szabolcs Nagy [this message]
2023-01-24 15:51 ` Jonathan Wakely
2023-01-26 19:18 ` Paul Pluzhnikov
2023-01-27 15:43 ` Jonathan Wakely
2023-02-05 18:39 ` Paul Pluzhnikov
2023-02-05 20:08 ` Florian Weimer
2023-02-05 21:51 ` Paul Pluzhnikov
2023-02-05 22:34 ` Florian Weimer
2023-02-05 22:55 ` Paul Pluzhnikov
2023-02-06 6:01 ` Florian Weimer
2023-02-06 16:25 ` Paul Pluzhnikov
2023-02-08 21:43 ` Paul Pluzhnikov
2023-01-25 20:50 ` Paul Pluzhnikov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y8/0O3XmWK+GJkCG@arm.com \
--to=szabolcs.nagy@arm.com \
--cc=dalias@libc.org \
--cc=fweimer@redhat.com \
--cc=jwakely@redhat.com \
--cc=libc-alpha@sourceware.org \
--cc=ppluzhnikov@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).