From: terra@gnome.org (Morten Welinder)
To: Joe.Buck@synopsys.com
Cc: gcc@gcc.gnu.org
Subject: Re: signed vs unsigned pointer warning
Date: Fri, 08 Oct 2004 18:57:00 -0000 [thread overview]
Message-ID: <20041008173153.E89761422D56@darter.rentec.com> (raw)
In-Reply-To: <20041008091714.A1695@synopsys.com> (message from Joe Buck on Fri, 8 Oct 2004 09:17:14 -0700)
Why can't an implementation define isxxx(c) to return something like
table_lookup[(unsigned)(c)]
?
Because isxxx needs to work with EOF, typically -1.
And regardless of the implementation's value of EOF, you cannot cast to
"unsigned char" either because that would make EOF collide with one of
the other 256 valid inputs.
So to summarize: someone screwed up with the definition of isxxx and it
is not fixable by the implementation. Therefore, get used to seeing
code like
const char *foo = whatever;
if (isspace ((unsigned char)*foo)) oink ();
no matter how ugly it is.
Morten
next prev parent reply other threads:[~2004-10-08 17:31 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-22 16:43 Morten Welinder
2004-09-22 17:17 ` Paul Koning
2004-09-22 17:27 ` Morten Welinder
2004-09-22 17:49 ` Dave Korn
2004-09-22 17:20 ` Dave Korn
2004-09-23 1:31 ` Andreas Schwab
2004-09-23 12:29 ` Dave Korn
2004-09-23 18:57 ` Joe Buck
2004-09-23 19:38 ` Dave Korn
2004-09-27 2:04 ` Jamie Lokier
2004-10-08 13:29 ` Nick Ing-Simmons
2004-10-08 13:32 ` Dave Korn
2004-10-08 17:20 ` Joe Buck
2004-10-08 17:28 ` Paul Jarc
2004-10-08 17:59 ` Joe Buck
2004-10-08 18:15 ` Dave Korn
2004-10-08 18:22 ` Joe Buck
2004-10-08 18:24 ` Jamie Lokier
2004-10-08 19:57 ` Paul Jarc
2004-10-09 7:05 ` Jamie Lokier
2004-10-09 8:48 ` Paul Jarc
2004-10-11 16:34 ` Richard Earnshaw
2004-10-08 18:57 ` Morten Welinder [this message]
2004-10-08 20:59 ` Matthias B.
2004-10-08 22:34 ` Paul Koning
2004-10-10 2:03 ` Matthias B.
2004-10-09 1:39 ` Andreas Schwab
2004-10-11 0:11 ` Kai Henningsen
-- strict thread matches above, loose matches on Subject: below --
2004-09-21 20:52 Richard Henderson
2004-09-21 22:36 ` Linus Torvalds
2004-09-22 14:35 ` Dave Korn
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=20041008173153.E89761422D56@darter.rentec.com \
--to=terra@gnome.org \
--cc=Joe.Buck@synopsys.com \
--cc=gcc@gcc.gnu.org \
/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).