From: Keith.S.Thompson+u@gmail.com
pozz 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-m
ssing-default-case.html
has not yet been updated (not surprisingly).
commit b474be668091301d4a214da922f0cb98d416dc6b
Author: Keith Thompson
Date: 2025-10-23 02:41:12 -0700
[clang-tidy][NFC] Clarify switch-missing-default-case doc (#164699)
(#164709)
Falling through a defaultless switch statement has well defined
behavior. Fixes https://github.com/llvm/llvm-project/issues/164699.
Credit for noticing this problem goes to user "pozz" on comp.lang.c,
Message-ID: <10da67g$3q59f$1@dont-email.me>
diff --git clang-tools-extra/docs/clang-tidy/checks/bugprone/swi
ch-missing-default-case.rst clang-tools-extra/docs/clang-tidy/ch
cks/bugprone/switch-missing-default-case.rst
index 648c2c208a4e..3ce862ff8afc 100644
--- clang-tools-extra/docs/clang-tidy/checks/bugprone/switch-mis
ing-default-case.rst
+++ clang-tools-extra/docs/clang-tidy/checks/bugprone/switch-mis
ing-default-case.rst
@@ -9,8 +9,8 @@ on covering cases with non-enums where the compiler may not
issue warnings.
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 program will continue execution without any defined
-behavior or handling.
+specified cases, the switch statement will do nothing and the program will
+continue execution without handling the value.
This check helps identify switch statements that are missing a default case,
allowing developers to ensure that all possible cases are handled properly.
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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