Re: .5 against 0.5f

From	David Brown <david.brown@hesbynett.no>
Newsgroups	comp.lang.c
Subject	Re: .5 against 0.5f
Date	2026-10-29 10:45 +0100
Organization	A noiseless patient Spider
Message-ID	<11bv4jd$37ch9$1@dont-email.me> (permalink)
References	(10 earlier) <11bttrp$2qvg6$1@dont-email.me> <11bu12l$2rgo2$4@kst.eternal-september.org> <11bu3kk$2svh8$1@dont-email.me> <868q3hmie0.fsf@linuxsc.com> <11bu8oi$2up7m$1@dont-email.me>

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On 29/10/2026 02:50, Steven G. Kargl wrote:
> On Wed, 28 Oct 2026 17:59:19 -0700, Tim Rentsch wrote:
> 
>> "Steven G. Kargl" <sgk@REMOVEtroutmask.apl.washington.edu> writes:
>>
>>> On Wed, 28 Oct 2026 16:39:00 -0700, Keith Thompson wrote:
>>>
>>>> (Also, you misspelled "ROFL", and you don't need parentheses on the
>>>> return statement, particularly if you dislike fluff.)
>>>
>>> Yeah, I was laugh too hard while typing ;-)
>>>
>>> Parentheses is a habit from BSD kernel source file style guide.
>>
>> Now is a good time to start unlearning that habit.
> 
> 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.

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?

> 
> Unlearning is not likely to happen.  I've been a long-time
> contributor to FreeBSD, and have no plans to stop.  Feel
> free to check the git history on FreeBSD libm sources.
> My finger prints are all over the code.  So, yeah, I know
> a enough about floating point arithmetic and C standard
> requirements to be dangerous.
> 
>>> % 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.
> 
> 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" :-)

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 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 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

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