From: Alejandro Colomar <alx+linux-hardening@kernel.org>
To: David Laight <david.laight.linux@gmail.com>
Cc: Alejandro Colomar <alx@kernel.org>,
linux-hardening@vger.kernel.org,
Krzysztof Kozlowski <krzk@kernel.org>,
"Maciej W. Rozycki" <macro@orcam.me.uk>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Andreas Schwab <schwab@linux-m68k.org>,
Andy Shevchenko <andy@kernel.org>,
Bartosz Golaszewski <brgl@kernel.org>,
Daniel Scally <djrscally@gmail.com>,
Danilo Krummrich <dakr@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Hans Verkuil <hverkuil-cisco@xs4all.nl>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Joe Perches <joe@perches.com>, Johan Hovold <johan@kernel.org>,
Kees Cook <kees@kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Len Brown <lenb@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linus Walleij <linusw@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Rob Herring <robh@kernel.org>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Saravana Kannan <saravanak@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Tom Zanussi <zanussi@kernel.org>,
linux-acpi@vger.kernel.org, driver-core@lists.linux.dev,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-gpio@vger.kernel.org
Subject: Re: [PATCH v3 5/5] string: Make strprefix() const-qualifier-generic
Date: Wed, 11 Nov 2026 12:28:15 +0100 [thread overview]
Message-ID: <avRQgOTnRtfec9fQ@devuan> (raw)
In-Reply-To: <20261111103438.2f822202@pumpkin>
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Hi David,
> Date: 2026-11-11 10:34:38+0000
> From: David Laight <david.laight.linux@gmail.com>
>
[...]
> > -static inline char *strprefix(const char *s, const char *prefix)
> > +#define strprefix(s, pfx) const_cast(CQChar_of(s) *, strprefix(s, pfx))
>
> Isn't in enough to do:
> #define strprefix(s, pfx) ((typeof(s))strprefix(s, pfx))
>
> which correctly preserves all qualifiers.
This would return a const void* if you pass a const void*. In general,
we shouldn't be passing a void* to a string function, but C allows this.
With CQChar_of(), you coerce a 'const void *' into a 'const char *'.
See also: <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3998.pdf#subsection.0.7.28.5>
Cheers,
Alex
--
<https://www.alejandro-colomar.es>
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prev parent reply other threads:[~2026-11-11 11:28 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-10 15:33 [PATCH v3 0/5] Add strprefix() and fix a bug with it Alejandro Colomar
2026-11-10 15:33 ` [PATCH v3 1/5] string: Add strprefix(), and deprecate str_has_prefix() Alejandro Colomar
2026-11-10 15:47 ` Joe Perches
2026-11-10 16:14 ` Alejandro Colomar
2026-11-11 8:43 ` Steven Rostedt
2026-11-10 15:33 ` [PATCH v3 2/5] device property: Fix fwnode_name_eq() for empty node names Alejandro Colomar
2026-11-10 15:33 ` [PATCH v3 3/5] stddef: Add const_cast() Alejandro Colomar
2026-11-11 10:25 ` David Laight
2026-11-11 10:51 ` Alejandro Colomar
2026-11-10 15:33 ` [PATCH v3 4/5] string: Add [C]QChar_of() and QVoid_of() Alejandro Colomar
2026-11-10 15:45 ` sashiko-bot
2026-11-11 0:03 ` Alejandro Colomar
2026-11-10 15:33 ` [PATCH v3 5/5] string: Make strprefix() const-qualifier-generic Alejandro Colomar
2026-11-10 15:44 ` sashiko-bot
2026-11-11 0:27 ` Alejandro Colomar
2026-11-10 16:32 ` Joe Perches
2026-11-10 23:27 ` Alejandro Colomar
2026-11-11 10:28 ` David Laight
2026-11-11 10:59 ` Alejandro Colomar
2026-11-11 10:34 ` David Laight
2026-11-11 11:28 ` Alejandro Colomar [this message]
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