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Groups > comp.lang.c > #394699
| From | Keith Thompson <Keith.S.Thompson+u@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: bugprone-switch-missing-default-case |
| Date | 2025-10-23 19:13 -0700 |
| Organization | None to speak of |
| Message-ID | <87y0p111ys.fsf@example.invalid> (permalink) |
| References | (2 earlier) <10dag3d$jkju$1@dont-email.me> <10damv3$ku01$1@dont-email.me> <87frbaohaa.fsf@example.invalid> <10dcj1l$3t7o6$1@dont-email.me> <87frb92op0.fsf@example.invalid> |
Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
> pozz <pozzugno@gmail.com> writes:
>> Il 22/10/2025 21:41, Keith Thompson ha scritto:
> [...]
>>> That document is poorly written. The phrase "without any defined
>>> behavior" strongly implies that the behavior is undefined, which is
>>> simply wrong.
>>> It says:
>>> When a switch statement lacks a default case, if a value is
>>> encountered that does not match any of the specified cases, the
>>> program will continue execution without any defined behavior or
>>> handling.
>>> It would be more accurate to say:
>>> When a switch statement lacks a default case, if a value is
>>> encountered that does not match any of the specified cases, the
>>> switch statement will do nothing and the program will continue
>>> execution without handling the value.
>>> A warning might be warranted, but the behavior is well defined.
>>
>> It is exactly what i wanted to read. Thanks for the explanation.
>>
>>> Note that the documentation is for the add-on tool clang-tidy, not for
>>> the clang compiler.
>>
>> Sure
>>
>>
>>> I've submitted a bug report :
>>> https://github.com/llvm/llvm-project/issues/164699
>
> My fix for this has been accepted into the llvm-project git repo.
>
> The web page
> https://clang.llvm.org/extra/clang-tidy/checks/bugprone/switch-missing-default-case.html
> has not yet been updated (not surprisingly).
And now it's been updated:
Switch statements without a default case can lead to unexpected
behavior and incomplete handling of all possible cases. When a
switch statement lacks a default case, if a value is encountered
that does not match any of the specified cases, the switch
statement will do nothing and the program will continue execution
without handling the value.
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */
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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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