mailing list of musl libc
 help / color / mirror / code / Atom feed
From: Rich Felker <dalias@libc.org>
To: Vincent Torri <vincent.torri@gmail.com>
Cc: musl@lists.openwall.com
Subject: Re: [musl] Warnings in fnmatch implementation
Date: Sun, 2 May 2021 11:18:51 -0400	[thread overview]
Message-ID: <20210502151850.GC2546@brightrain.aerifal.cx> (raw)
In-Reply-To: <CAMq1adqqqgb7U+Gb3-ov6-fOgcpdVRGBW-_BinrwqRFGw34ZKw@mail.gmail.com>

On Sun, May 02, 2021 at 02:11:03PM +0200, Vincent Torri wrote:
> Hello
> 
> 
> when compiling fnmatch.c, I have there following warnings :
> 
> 
> fnmatch.c: In function 'str_next':
> fnmatch.c:34:13: warning: comparison of integer expressions of
> different signedness: 'char' and 'unsigned int' [-Wsign-compare]
>    34 |  if (str[0] >= 128U) {
>       |             ^~
> fnmatch.c: In function 'pat_next':
> fnmatch.c:87:13: warning: comparison of integer expressions of
> different signedness: 'char' and 'unsigned int' [-Wsign-compare]
>    87 |  if (pat[0] >= 128U) {
>       |             ^~
> fnmatch.c: In function 'match_bracket':
> fnmatch.c:129:24: warning: comparison of integer expressions of
> different signedness: 'unsigned int' and 'int' [-Wsign-compare]
>   129 |     if ((unsigned)k-wc <= wc2-wc ||
>       |                        ^~
> fnmatch.c:130:28: warning: comparison of integer expressions of
> different signedness: 'unsigned int' and 'int' [-Wsign-compare]
>   130 |         (unsigned)kfold-wc <= wc2-wc)
>       |                            ^~
> fnmatch.c:150:10: warning: comparison of integer expressions of
> different signedness: 'char' and 'unsigned int' [-Wsign-compare]
>   150 |   if (*p < 128U) {
>       |          ^
> fnmatch.c: In function 'fnmatch_internal':
> fnmatch.c:232:13: warning: comparison of integer expressions of
> different signedness: 'char' and 'unsigned int' [-Wsign-compare]
>   232 |   if (s[-1] < 128U || MB_CUR_MAX==1) s--;
>       |             ^
> 
> All the 128U can be replaced by just 128, and (unsigned) by just (int)

They definitely can't be replaced with just 128. Changing them to 128
changes the meaning of the expression and introduces a serious bug
(prevents handling of any non-ASCII characters on archs where plain
char is a signed type). For example -64 < 128 is true but -64 < 128U
is false.

Rich

      reply	other threads:[~2021-05-02 15:19 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-02 12:11 Vincent Torri
2021-05-02 15:18 ` Rich Felker [this message]

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=20210502151850.GC2546@brightrain.aerifal.cx \
    --to=dalias@libc.org \
    --cc=musl@lists.openwall.com \
    --cc=vincent.torri@gmail.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).