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From: David Brown <david.brown@hesbynett.no>
Newsgroups: comp.lang.c
Subject: Re: how to make a macro work as a single line if stmt without braces
Date: Mon, 23 Sep 2024 08:16:07 +0200
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On 22/09/2024 22:39, Keith Thompson wrote:
> Bart <bc@freeuk.com> writes:
>> On 22/09/2024 16:11, Kaz Kylheku wrote:
> [...]
>>> Also GCC has been able to diagnose misleading indentation for some
>>> years now.
>>
>> How many years was that out of the last 52? How exactly do you turn it
>> on? Since -Wall -Wpedantic -Wextra doesn't report it.
> 
> The -Wmisleading-indentation option was added to gcc on 2015-05-12,
> and incorporated into -Wall 2015-12-10.  gcc 6.1.0 has the option
> and includes it in -Wall; gcc 5.3.0 does not.  (Are you using a gcc
> release that old?)  It uses the -ftabstop= option (defaulting to 8)
> to determine whether indentation lines up or not.
> 
> Inconsistent tabstops and mixing of spaces and tabs can certainly
> cause problems.
> 

That would be detected quite easily if the default for -ftabstop were, 
say, 27.  Then the chance of accidentally matching indents with tabs and 
spaces would be negligible.