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Re: Why AC_C_CHAR_UNSIGNED?
From: |
Ralf Wildenhues |
Subject: |
Re: Why AC_C_CHAR_UNSIGNED? |
Date: |
Mon, 23 Jun 2008 19:13:59 +0200 |
User-agent: |
Mutt/1.5.17+20080114 (2008-01-14) |
Hello,
* Richard Ash wrote on Mon, Jun 23, 2008 at 06:27:57PM CEST:
> Hallvard B Furuseth wrote:
> > What's the point of the AC_C_CHAR_UNSIGNED macro?
> > "If the C type `char' is unsigned, define `__CHAR_UNSIGNED__',
> > unless the C compiler predefines it."
> >
> > This is what <limits.h> is for. If you want to know if char is
> > unsigned, try #if CHAR_MIN == 0. I would suggest at least mentioning
> > that option in the doc for AC_C_CHAR_UNSIGNED.
FWIW, I don't see a problem with this; but I'm not the most experienced
in this area.
> That assumes you have a correct limits.h on the system, which is an
> assumption you can't necessarily make on an old enough system.
Do you have any specific examples here, found outside of a museum?
Current Autoconf more or less tells users to assume C89 for new
programs, and limits.h exists in a free-standing implementation, too.
> It also
> assumes that the compiler matches the headers, which again might be wrong
> if someone has messed up a third party compiler install.
I don't think Autoconf should need to cater for intentionally broken
systems (except maybe in order to solve bootstrapping issues).
Cheers,
Ralf
- Why AC_C_CHAR_UNSIGNED?, Hallvard B Furuseth, 2008/06/23
- Re: Why AC_C_CHAR_UNSIGNED?, Richard Ash, 2008/06/23
- Re: Why AC_C_CHAR_UNSIGNED?,
Ralf Wildenhues <=
- Re: Why AC_C_CHAR_UNSIGNED?, Bob Friesenhahn, 2008/06/23
- Re: Why AC_C_CHAR_UNSIGNED?, Stepan Kasal, 2008/06/24
- Re: Why AC_C_CHAR_UNSIGNED?, Ralf Wildenhues, 2008/06/24
- Re: Why AC_C_CHAR_UNSIGNED?, Stepan Kasal, 2008/06/25
- Re: Why AC_C_CHAR_UNSIGNED?, Bob Friesenhahn, 2008/06/25
- Re: Why AC_C_CHAR_UNSIGNED?, Andreas Schwab, 2008/06/25
- Re: Why AC_C_CHAR_UNSIGNED?, Stepan Kasal, 2008/06/26
- Re: Why AC_C_CHAR_UNSIGNED?, Ralf Wildenhues, 2008/06/26
- Re: Why AC_C_CHAR_UNSIGNED?, Stepan Kasal, 2008/06/26
- Re: Why AC_C_CHAR_UNSIGNED?, Hallvard B Furuseth, 2008/06/28