Re: .5 against 0.5f

From	cross@spitfire.i.gajendra.net (Dan Cross)
Newsgroups	comp.lang.c
Subject	Re: .5 against 0.5f
Date	2026-10-29 14:56 +0000
Organization	PANIX Public Access Internet and UNIX, NYC
Message-ID	<11bvmqg$7ip$1@reader2.panix.com> (permalink)
References	<11bpvs7$1e6kc$2@dont-email.me> <868q3hmie0.fsf@linuxsc.com> <11bu8oi$2up7m$1@dont-email.me> <11bv4jd$37ch9$1@dont-email.me>

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In article <11bv4jd$37ch9$1@dont-email.me>,
David Brown  <david.brown@hesbynett.no> wrote:
>> [snip]
>> Why?  What harm do the parentheses cause?
>
>I can't see that parentheses here cause any actual harm - but they are
>certainly unnecessary fluff, and do no good.

I agree; in my own code, I do not generally use parentheses
around the expression I give in a `return` statement.  But often
our code is not our own, in the sense that we're constrained by
working on a much larger project and there are externally
imposed constraints that we must honor.  I don't have to like
them but, but I do have to abide by them.

>Every extra level of parentheses adds to the cognitive effort required
>to understand and interpret an expression.  It takes longer to read, and
>has a higher chance of misinterpretation.  If the parenthesis are
>necessary - "(a + b) * c" - then this is clearly a cost worth paying.
>Sometimes parentheses are not necessary, but /reduce/ the cognitive
>effort, such as "(a > 2) && (a < 5)".  Again, the parentheses are then a
>good thing (albeit subjectively).
>
>But in "return (x);", they add nothing but cognitive effort.  The C
>programmer's brain has to consider and reject the possibility that this
>is a function call or a macro invocation.  The effort is small, but
>nonetheless wasted.
>
>Let me put it another way.  What benefit do you think there is from
>these parentheses?  Why does the FreeBSD style guide recommend them?  I
>can see benefits in consistency of style once that usage has been
>established, but why have them in the first place?

I mostly agree with you.  But when working on a large project,
that spans many decades, with many different contributers,
having uniformity is good.  You mention cogitive load, but I
submit that it is strictly worse in that regard to have to deal
with multiple stylistic differences based on individual
preference.

My example is the Google monorepo.  When I left Google, it
contained about 2BLOC of code.  All of which more or less
conformed to Google's mandatory style "guides" (which were only
"guides" insofar as allowing people to get explicit exemptions
for very specific reasons from a small group of extremely senior
engineers: like, Sanjay Ghemawat and Jeff Dean type of senior).

Personally, I despised the style rules for almost all languages
Google used; I thought the code was ugly.  *But*, after a few
weeks working in the codebase, they became all but invisible; I
had to consciously think about them to remember my aesthetic
objections.  Furthermore, I claim that rigid adherence to _a_
set of rules, no matter how ugly I thought they were, was a big
factor in allowing Google to scale to tends of thousands of
engineers working concurrently in a multi-billion line codebase.

Put another way, it is more important to have _a_ style that is
used uniformly, while it is relatively less important what rules
that style imposes.

>>>> [snip]
>>>> % man 9 style
>>>> ...
>>>>
>>>>       Values in return statements should be enclosed in parentheses.
>>>>
>>>>
>>>> I also have debugging macros RETURNI() that require parens.
>>>
>>> That strengthens the motivation not to use parentheses with
>>> return statements, to emphasize that they are different from
>>> the macros.

A metanote, not to David, but of course, reference to the
`style(9)` man page _strengthens_ the argument for
parenthesizing return'ed expressions when working with FreeBSD
code.  In fairness, it wasn't clear that that was the original
context.

>> Do you ignore the style requirements of all the projects
>> that you may have worked on, and simply use whatever
>> your personal preferences are?
>
>When working on code with particular style requirements, it makes sense
>to follow those style requirements - even if you disagree with the
>requirements.  When working on other code, you are then freed from
>following rules that are unnecessary or counter-productive.
>
>If I were contributing code to FreeBSD and it /requires/ parentheses in
>return statements for the code to be accepted, I'd put parentheses in
>return statements.  If it merely /recommends/ them, I would not do so -
>but would change my mind if other FreeBSD contributors made a fuss about
>it.  In no other code would I use them, and in code reviews I would ask
>for them to be removed.
>
>But I would not bother about them in throw-away Usenet code, except if
>the post was complaining about other unnecessary "fluff" :-)

I do not find the amount of heat this has generated particularly
useful.  The parentheses may be superfluous, but they're not
wrong, and if OP prefers to include them, it does no harm; in
this case, there's a very good reason: OP works with FreeBSD
code often, which mandates them; maintaining two separate styles
to appease the USENET crowd is probably more cognitive effort
than mentally blocking them out for a `return`.

	- Dan C.

Thread

.5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-27 11:53 +0100
  Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-27 17:45 +0000
    Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-27 18:50 +0100
      Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-27 19:01 +0000
        Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-27 20:15 +0100
          Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-27 19:54 +0000
            Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-27 13:10 -0700
              Re: .5 against 0.5f steve g <Sgonedes1977@gmail.com> - 2026-10-28 02:20 -0400
            Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-27 21:35 +0100
            Re: .5 against 0.5f James Kuyper <jameskuyper@alumni.caltech.edu> - 2026-10-27 18:00 -0400
              Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-27 22:15 +0000
              Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-28 06:54 -0700
          Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-27 21:57 +0100
            Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-27 14:18 -0700
          Re: .5 against 0.5f steve g <Sgonedes1977@gmail.com> - 2026-10-28 02:19 -0400
            Re: .5 against 0.5f Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-28 21:54 +0000
              Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-28 14:58 -0700
      Re: .5 against 0.5f steve g <Sgonedes1977@gmail.com> - 2026-10-28 02:11 -0400
        Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-27 23:21 -0700
    Re: .5 against 0.5f scott@slp53.sl.home (Scott Lurndal) - 2026-10-27 18:40 +0000
      Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-27 12:29 -0700
        Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-27 13:11 -0700
          Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-27 13:25 -0700
      Re: .5 against 0.5f Michael S <already5chosen@yahoo.com> - 2026-10-27 21:43 +0200
        Re: .5 against 0.5f Michael S <already5chosen@yahoo.com> - 2026-10-27 22:05 +0200
          Re: .5 against 0.5f Michael S <already5chosen@yahoo.com> - 2026-10-27 22:51 +0200
      Re: .5 against 0.5f Kaz Kylheku <046-301-5902@kylheku.com> - 2026-10-27 20:05 +0000
        Re: .5 against 0.5f bartc <bc@freeuk.com> - 2026-10-27 21:03 +0000
        Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-27 15:41 -0700
          Re: .5 against 0.5f scott@slp53.sl.home (Scott Lurndal) - 2026-10-28 16:23 +0000
      Re: .5 against 0.5f steve g <Sgonedes1977@gmail.com> - 2026-10-28 02:25 -0400
      Re: .5 against 0.5f makendo <makendo@makendo.invalid> - 2026-10-29 18:04 +0800
        Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 05:01 -0700
          Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 13:55 +0100
            Re: .5 against 0.5f bartc <bc@freeuk.com> - 2026-10-29 14:32 +0000
          Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 23:19 +0100
        Re: .5 against 0.5f Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-30 00:50 +0000
          Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-30 05:01 +0100
            Re: .5 against 0.5f "chine.bleu" <chine.bleu@yahoo.com> - 2026-10-30 02:39 -0700
              Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-30 11:06 +0100
                Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-30 11:12 -0700
              Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-30 14:07 +0100
            Re: .5 against 0.5f scott@slp53.sl.home (Scott Lurndal) - 2026-10-30 13:55 +0000
              Re: .5 against 0.5f "chine.bleu" <chine.bleu@yahoo.com> - 2026-10-30 07:45 -0700
          Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 21:17 -0700
    Re: .5 against 0.5f Kaz Kylheku <046-301-5902@kylheku.com> - 2026-10-27 19:58 +0000
    Re: .5 against 0.5f James Kuyper <jameskuyper@alumni.caltech.edu> - 2026-10-27 17:43 -0400
      Re: .5 against 0.5f James Kuyper <jameskuyper@alumni.caltech.edu> - 2026-10-27 18:06 -0400
        Re: .5 against 0.5f Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-28 00:49 +0000
          Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-27 18:23 -0700
            Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-28 16:38 +0100
              Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-28 13:27 -0700
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 00:08 +0100
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-28 16:56 -0700
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 18:55 +0100
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 09:30 +0100
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 04:54 -0700
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 19:57 +0100
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 20:56 +0100
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 23:06 +0100
                Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-29 13:39 -0700
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 16:56 -0700
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-30 04:38 +0100
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-30 09:11 +0100
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-30 14:54 +0100
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-30 15:25 +0100
                Re: .5 against 0.5f cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-30 14:45 +0000
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-30 12:02 -0700
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-30 21:01 +0100
          Re: .5 against 0.5f James Kuyper <jameskuyper@alumni.caltech.edu> - 2026-10-27 21:41 -0400
            Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-28 08:45 +0100
          Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-28 01:50 +0000
            Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-28 07:32 +0100
              Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-28 07:51 +0100
                Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-28 07:55 +0100
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-28 16:27 +0000
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-28 17:44 +0100
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-28 16:22 +0000
                Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-28 19:15 +0100
                Re: .5 against 0.5f fir <profesor.fir@gmail.com> - 2026-10-28 19:47 +0100
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-28 19:10 +0000
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-28 13:31 -0700
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-28 22:44 +0000
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 00:27 +0100
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-28 16:39 -0700
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-29 00:22 +0000
                Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-28 17:59 -0700
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-29 01:50 +0000
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 10:45 +0100
                Re: .5 against 0.5f cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-29 14:56 +0000
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-29 16:34 +0000
                Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-29 15:47 -0700
                Re: .5 against 0.5f cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-30 01:17 +0000
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 16:46 -0700
                Re: .5 against 0.5f James Kuyper <jameskuyper@alumni.caltech.edu> - 2026-10-29 11:56 -0400
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-29 17:57 +0000
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 16:06 -0700
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-30 00:21 +0000
                Re: .5 against 0.5f cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-29 19:49 +0000
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 22:55 +0100
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 16:29 -0700
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-30 03:57 +0100
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 20:53 -0700
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-30 05:06 +0100
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-30 09:33 +0100
                Re: .5 against 0.5f cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-30 10:58 +0000
                Re: .5 against 0.5f Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-29 23:46 +0000
                Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-29 18:37 -0700
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-30 04:22 +0100
                Re: .5 against 0.5f Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2026-10-29 17:58 +0100
                Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-29 15:42 -0700
                Re: .5 against 0.5f cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-30 01:27 +0000
                Re: .5 against 0.5f "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> - 2026-10-30 02:08 +0000
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 19:37 -0700
          Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-28 08:39 +0100
            Re: .5 against 0.5f Michael S <already5chosen@yahoo.com> - 2026-10-28 22:25 +0200
              Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 10:48 +0100
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-29 04:59 -0700
            Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-28 14:26 -0700
              Re: .5 against 0.5f Michael S <already5chosen@yahoo.com> - 2026-10-29 00:12 +0200
                Re: .5 against 0.5f bartc <bc@freeuk.com> - 2026-10-28 22:33 +0000
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 11:01 +0100
                Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-28 16:05 -0700
                Re: .5 against 0.5f Michael S <already5chosen@yahoo.com> - 2026-10-30 11:58 +0200
                Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 10:59 +0100
            Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-28 14:34 -0700
              Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-29 11:06 +0100
          Re: .5 against 0.5f tTh <tth@none.invalid> - 2026-10-28 15:08 +0100
            Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-28 07:49 -0700
          Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-28 14:36 -0700
      Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-27 15:53 -0700
        Re: .5 against 0.5f James Kuyper <jameskuyper@alumni.caltech.edu> - 2026-10-27 21:55 -0400
          Re: .5 against 0.5f Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2026-10-27 19:02 -0700
        Re: .5 against 0.5f David Brown <david.brown@hesbynett.no> - 2026-10-28 08:56 +0100
      Re: .5 against 0.5f Tim Rentsch <tr.17687@z991.linuxsc.com> - 2026-10-28 08:01 -0700
  Re: .5 against 0.5f "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-27 13:08 -0700
  Re: .5 against 0.5f Lynn McGuire <lynnmcguire5@gmail.com> - 2026-10-30 22:00 -0500
    Re: .5 against 0.5f Lynn McGuire <lynnmcguire5@gmail.com> - 2026-10-30 22:01 -0500

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