From: "Dave Korn" <dk@artimi.com>
To: "'Nick Ing-Simmons'" <nick@ing-simmons.net>, <jamie@shareable.org>
Cc: <gcc@gcc.gnu.org>, "'Morten Welinder'" <terra@gnome.org>
Subject: RE: signed vs unsigned pointer warning
Date: Fri, 08 Oct 2004 13:32:00 -0000 [thread overview]
Message-ID: <NUTMEGLBwg9MvuHdPtn00000327@NUTMEG.CAM.ARTIMI.COM> (raw)
In-Reply-To: <20041008130623.9516.4@llama.elixent.com>
> -----Original Message-----
> From: Nick Ing-Simmons [mailto:nick@ing-simmons.net]
> Sent: 08 October 2004 14:06
> >This is a real typical bug. Just recently a bug was found in
> >curl-library, quite a popular little library, which calls
> >isspace(char). The bug was missed for a long time, as it is only
> >triggered with characters with the MSB set, which do not occur often
> >in HTTP headers.
>
> I am reasnably sure that on old SunOS4 systems passing signed char
> to isxxx() was normal and worked. The lookup tables where defined
> in such a way that 128 or so entries before the normal table
> replicated
> the 2nd half.
>
> Snag is it is hard to define such arrays in C.
Well, you don't, you just define a "type * const" pointer to the 128'th
entry of the real underlying, e.g. instead of saying
unsigned char isXXX_flags_array[256]
you say
static unsigned char __isXXX_flags_array[256];
unsigned char * const isXXX_flags_array = &__is_flags_array[128];
Or at any rate, I use that idiom quite a lot.
cheers,
DaveK
--
Can't think of a witty .sigline today....
next prev parent reply other threads:[~2004-10-08 13:13 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 [this message]
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
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
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