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Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ?

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On Thu, 18 Aug 2022 09:58:59 +0200
"R.Wieser" <address@not.available> wrote:
>Ike,
>
>> First, == binds stronger than & in C and C++
>
>Yep, thats the part that I missed.
>
>>  flags & flagMask == flagMask
>>
>> is interpreted as
>>
>>  flags & (flagMask == flagMask)
>>
>> which can be simplified to
>>
>>  flags & 1
>>
>> which is true if the least significant bit of flags is set.
>
>IOW, while that "superset" is technically true, its also confusing the
>matter by being unspecific.
>
>but even in that case, for flags = 1 and flagMask = 0,
>> -->  flags is a superset of flagMask
>> -->  flags != flagMask
>> -->  ((flags & flagMask) == flagMask)  equals  ((1 & 0) == 0)
>>                                       equals  (0 == 0)
>>                                       equals  true
>
>As far as I understood that was exactly what they where aiming for.
>
>Thanks for the precedence heads-up.

If in doubt just use brackets. They're free.

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flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? "R.Wieser" <address@not.available> - 2022-08-18 07:55 +0200
  Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Ike Naar <ike@sdf.org> - 2022-08-18 06:52 +0000
    Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? "R.Wieser" <address@not.available> - 2022-08-18 09:58 +0200
      Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Muttley@dastardlyhq.com - 2022-08-18 14:50 +0000
        Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? "R.Wieser" <address@not.available> - 2022-08-18 17:12 +0200
        Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? scott@slp53.sl.home (Scott Lurndal) - 2022-08-18 15:29 +0000
          Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-18 16:43 +0100
            Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? scott@slp53.sl.home (Scott Lurndal) - 2022-08-18 16:10 +0000
            Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? David Brown <david.brown@hesbynett.no> - 2022-08-18 21:19 +0200
              Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Manfred <noname@add.invalid> - 2022-08-19 02:57 +0200
                Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? David Brown <david.brown@hesbynett.no> - 2022-08-19 08:29 +0200
            Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-08-19 08:12 -0700
          Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2022-08-18 16:47 +0100
            Re: flags & flagMask == flagMask can be true for flags != flagMask if Muttley@dastardlyhq.com - 2022-08-18 15:50 +0000
            Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-18 10:46 -0700
              Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-18 11:30 -0700
          Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Muttley@dastardlyhq.com - 2022-08-18 15:47 +0000
        Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-08-19 08:53 -0700
          Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? David Brown <david.brown@hesbynett.no> - 2022-08-19 18:00 +0200
          Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Muttley@dastardlyhq.com - 2022-08-19 16:10 +0000
            Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-08-19 16:45 -0700
    Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Juha Nieminen <nospam@thanks.invalid> - 2022-08-19 06:01 +0000
      Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-19 16:07 +0100
      Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-19 16:08 +0100
  Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2022-08-18 16:14 +0100
    Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? "R.Wieser" <address@not.available> - 2022-08-18 18:10 +0200
  Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-08-18 11:56 -0700
    Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? "R.Wieser" <address@not.available> - 2022-08-18 21:31 +0200
      Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-08-18 21:24 -0700
        Re: flags & flagMask == flagMask can be true for flags != flagMask if flags is a superset of flagMask ? "R.Wieser" <address@not.available> - 2022-08-19 09:36 +0200

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