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Groups > comp.lang.c > #394701

Re: bugprone-switch-missing-default-case

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: bugprone-switch-missing-default-case
Date 2025-10-24 09:22 +0200
Organization A noiseless patient Spider
Message-ID <10df9fk$2dph4$2@dont-email.me> (permalink)
References (6 earlier) <10dd215$3totj$2@dont-email.me> <10ddg8q$1r5el$1@dont-email.me> <10ddkb2$1tadp$1@dont-email.me> <10de3sh$24ftv$1@dont-email.me> <10de8bn$1hhn$1@news.gegeweb.eu>

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On 23/10/2025 23:57, tTh wrote:
> On 10/23/25 22:40, David Brown wrote:
>> Personally, I usually prefer to have the "last", "max", or "count" 
>> indicator outside the enumeration :
>>
>>      enum E1 { A, B, C, D };
>>      static const int count_of_E1 = D;
> 
>     Why did you use 'static' here ?
> 

The enumeration definition will either be in a C file, in which case the 
const should be "static" because it is local to the file, or it will be 
in a header, in which case making the small const "static" can be vastly 
more efficient in many ways.  I have been assuming that this definition 
is at file scope, as most type declarations are, rather than local to a 
function.  If it is local to a function, then decent compilers will give 
the same resulting code with or without the static.


But I see I have made a mistake here - I have mixed up with C++.  You 
can't use static_assert in C with a "const" like this for compile-time 
checking.  So in C, prior to C23, you actually need to write (with the 
+1 correction to my original example) :

       enum E1 { A, B, C, D };
       enum { count_of_E1 = D + 1 };

if you want to be able to write :

	_Static_assert(count_of_E1 == 4, "Checking enumeration");

With C23, you could have "constexpr int count_of_E1 = D;" and use it in 
a static assertion.  (constexpr declarations always have internal 
linkage, so no "static" is needed.)

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Thread

bugprone-switch-missing-default-case pozz <pozzugno@gmail.com> - 2025-10-22 10:56 +0200
  Re: bugprone-switch-missing-default-case Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-10-22 11:32 +0200
    Re: bugprone-switch-missing-default-case Richard Harnden <richard.nospam@gmail.invalid> - 2025-10-22 12:44 +0100
      Re: bugprone-switch-missing-default-case Thiago Adams <thiago.adams@gmail.com> - 2025-10-22 10:05 -0300
        Re: bugprone-switch-missing-default-case Kaz Kylheku <643-408-1753@kylheku.com> - 2025-10-22 18:22 +0000
          Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-23 09:12 +0200
            Re: bugprone-switch-missing-default-case Thiago Adams <thiago.adams@gmail.com> - 2025-10-23 08:03 -0300
              Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-23 17:06 +0200
                Re: bugprone-switch-missing-default-case Thiago Adams <thiago.adams@gmail.com> - 2025-10-23 13:15 -0300
                Re: bugprone-switch-missing-default-case bart <bc@freeuk.com> - 2025-10-23 17:46 +0100
                Re: bugprone-switch-missing-default-case Thiago Adams <thiago.adams@gmail.com> - 2025-10-23 14:12 -0300
                Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-23 22:40 +0200
                Re: bugprone-switch-missing-default-case scott@slp53.sl.home (Scott Lurndal) - 2025-10-23 20:51 +0000
                Re: bugprone-switch-missing-default-case Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-10-23 16:21 -0700
                Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-24 08:59 +0200
                Re: bugprone-switch-missing-default-case scott@slp53.sl.home (Scott Lurndal) - 2025-10-24 15:51 +0000
                Re: bugprone-switch-missing-default-case tTh <tth@none.invalid> - 2025-10-23 23:57 +0200
                Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-24 09:22 +0200
                Re: bugprone-switch-missing-default-case antispam@fricas.org (Waldek Hebisch) - 2025-10-23 23:23 +0000
                Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-24 09:53 +0200
      Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-22 15:41 +0200
        Re: bugprone-switch-missing-default-case Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-10-22 16:05 +0200
          Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-22 17:23 +0200
            Re: bugprone-switch-missing-default-case Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-10-23 04:54 +0200
              Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-23 09:30 +0200
            Re: bugprone-switch-missing-default-case antispam@fricas.org (Waldek Hebisch) - 2025-10-23 22:40 +0000
        Re: bugprone-switch-missing-default-case Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-10-22 12:41 -0700
          Re: bugprone-switch-missing-default-case pozz <pozzugno@gmail.com> - 2025-10-23 08:47 +0200
            Re: bugprone-switch-missing-default-case Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-10-23 16:17 -0700
              Re: bugprone-switch-missing-default-case Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-10-23 19:13 -0700
          Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-23 10:44 +0200
      Re: bugprone-switch-missing-default-case Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-10-22 15:56 +0200
        Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-22 17:25 +0200
          Re: bugprone-switch-missing-default-case Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2025-10-23 04:39 +0200
            Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-23 09:08 +0200
          Re: bugprone-switch-missing-default-case Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-10-23 16:31 -0700
            Re: bugprone-switch-missing-default-case David Brown <david.brown@hesbynett.no> - 2025-10-24 10:09 +0200
  Re: bugprone-switch-missing-default-case Kaz Kylheku <643-408-1753@kylheku.com> - 2025-10-22 18:13 +0000

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