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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: how to make a macro work as a single line if stmt without braces
Date: Sun, 22 Sep 2024 13:39:36 -0700
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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.

> It is a failure in the design of the language.

I wouldn't quite go that far, but I partly agree with you.  Perl
requires braces on compound statements, and I've largely adopted
that style in my own C code.  If C had required braces (requiring
a compound-statement in most contexts that currently require a
statement), certain errors would have been more difficult to make.
And you could still write one-line if statements in the cases
where they might be clearer:

    if (cond1) { do_this(); }
    if (cond2) { do_that(); }
    if (cond3) { do_the_other(); }

However, there is zero chance that this will be changed in a future
version of C.  It would break too much existing code.  Which is
why we're discussing ways to write reliable code given the existing
language rules.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */