From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: Re: #define __MUSL__ in features.h
Date: Thu, 15 Mar 2018 18:38:01 -0400 [thread overview]
Message-ID: <20180315223801.GP1436@brightrain.aerifal.cx> (raw)
In-Reply-To: <20180315214656.GX4418@port70.net>
[-- Attachment #1: Type: text/plain, Size: 1197 bytes --]
On Thu, Mar 15, 2018 at 10:46:56PM +0100, Szabolcs Nagy wrote:
> * Rich Felker <dalias@libc.org> [2018-03-15 15:32:44 -0400]:
> > Perhaps this should be documented more explicitly, but there is no
> > guarantee that building with -Werror[=anything except warnings which
> > are constraint violations in C] will succeed, especially when GCC is
> > not honoring its usual promise not to produce warnings for code
> > expanded from macros from -isystem paths. I did just test and indeed
> > the warning is produced with gcc 6.3.0.
> >
>
> how did you reproduce it? -Wsign-conversion (or -Wconversion)
> is not even enabled by
Manually using -Wsign-conversion with the attached program.
> what would be acceptable is some form of assertion that the
> fd must be positive, however it seems nobody cares about this
> warning so neither gcc nor clang tries to use available range
> information to see if conversion can ever change the result:
>
> if (d > 0) FD_SET(d,s);
>
> still warns.
This basically settles it that it's a buggy warning option.
> if users care about this warning they should first make
> sure the compilers dont emit false positives for such
> trivial cases.
Agreed.
Rich
[-- Attachment #2: signed-conversion.c --]
[-- Type: text/plain, Size: 111 bytes --]
#include <sys/select.h>
int main(int argc, char **argv)
{
fd_set fds;
FD_ZERO(&fds);
FD_SET(argc, &fds);
}
next prev parent reply other threads:[~2018-03-15 22:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-15 15:55 dgutson .
2018-03-15 18:39 ` Rich Felker
2018-03-15 18:48 ` Martin Galvan
2018-03-15 18:53 ` Rich Felker
2018-03-15 19:00 ` dgutson .
2018-03-15 19:13 ` dgutson .
2018-03-15 19:42 ` Rich Felker
2018-03-15 20:16 ` u-uy74
2018-03-15 20:44 ` u-uy74
2018-03-15 19:37 ` Rich Felker
2018-03-15 19:42 ` dgutson .
2018-03-15 19:02 ` Martin Galvan
2018-03-15 19:32 ` Rich Felker
2018-03-15 19:37 ` dgutson .
2018-03-15 19:43 ` Rich Felker
2018-03-15 19:52 ` dgutson .
2018-03-15 21:46 ` Szabolcs Nagy
2018-03-15 22:38 ` Rich Felker [this message]
2018-03-15 18:51 ` dgutson .
2018-03-15 21:06 ` Markus Wichmann
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=20180315223801.GP1436@brightrain.aerifal.cx \
--to=dalias@libc.org \
--cc=musl@lists.openwall.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.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
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 NNTP newsgroup(s).