| Message ID | 84781fce2c3145a86d043d4c6b3b463af40eeed0.1699606819.git.manos.pitsidianakis@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Add QEMU_WARN_UNUSED_RESULT function attribute | expand |
On Fri, Nov 10, 2023 at 11:16:38AM +0200, Manos Pitsidianakis wrote: > This commit adds QEMU_WARN_UNUSED_RESULT, a macro for the gcc function > attribute `warn_unused_result`. The utility of this attribute is to > ensure functions that return values that need to be inspected are not > ignored by the caller. > > Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> > --- > include/qemu/compiler.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h > index c797f0d457..7ddbf1f1cf 100644 > --- a/include/qemu/compiler.h > +++ b/include/qemu/compiler.h > @@ -212,6 +212,20 @@ > # define QEMU_USED > #endif > > +/* > + * From GCC documentation: > + * > + * The warn_unused_result attribute causes a warning to be emitted if a > + * caller of the function with this attribute does not use its return value. > + * This is useful for functions where not checking the result is either a > + * security problem or always a bug, such as realloc. > + */ > +#if __has_attribute(warn_unused_result) > +# define QEMU_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) > +#else > +# define QEMU_WARN_UNUSED_RESULT > +#endif GLib already provides us G_GNUC_WARN_UNUSED_RESULT so don't add this. With regards, Daniel
On 10/11/23 10:16, Manos Pitsidianakis wrote: > This commit adds QEMU_WARN_UNUSED_RESULT, a macro for the gcc function > attribute `warn_unused_result`. The utility of this attribute is to > ensure functions that return values that need to be inspected are not > ignored by the caller. > > Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> > --- > include/qemu/compiler.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > +/* > + * From GCC documentation: > + * > + * The warn_unused_result attribute causes a warning to be emitted if a > + * caller of the function with this attribute does not use its return value. > + * This is useful for functions where not checking the result is either a > + * security problem or always a bug, such as realloc. > + */ > +#if __has_attribute(warn_unused_result) > +# define QEMU_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) > +#else > +# define QEMU_WARN_UNUSED_RESULT > +#endif FWIW I sometimes use: +#if __has_attribute(nonnull) +# define QEMU_NONNULL(indexes...) __attribute__((nonnull((indexes)))) +#else +# define QEMU_NONNULL(indexes...) +#endif when doing tree-wide refactors, then remove the attribute because prototypes become really ugly.
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index c797f0d457..7ddbf1f1cf 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -212,6 +212,20 @@ # define QEMU_USED #endif +/* + * From GCC documentation: + * + * The warn_unused_result attribute causes a warning to be emitted if a + * caller of the function with this attribute does not use its return value. + * This is useful for functions where not checking the result is either a + * security problem or always a bug, such as realloc. + */ +#if __has_attribute(warn_unused_result) +# define QEMU_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) +#else +# define QEMU_WARN_UNUSED_RESULT +#endif + /* * Ugly CPP trick that is like "defined FOO", but also works in C * code. Useful to replace #ifdef with "if" statements; assumes
This commit adds QEMU_WARN_UNUSED_RESULT, a macro for the gcc function attribute `warn_unused_result`. The utility of this attribute is to ensure functions that return values that need to be inspected are not ignored by the caller. Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> --- include/qemu/compiler.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+)