> From: Mattias Rönnblom [mailto:mattias.ronnb...@ericsson.com] > Sent: Monday, 11 April 2022 17.16 > > This patch adds a wrapper macro __rte_warn_unused_result for the > warn_unused_result function attribute. > > Marking a function __rte_warn_unused_result will make the compiler > emit a warning in case the caller does not use the function's return > value. > > Changes since RFC: > * Include usage recommendation and GCC peculiarities in the macro > documentation. > > Acked-by: Bruce Richardson <bruce.richard...@intel.com> > > Signed-off-by: Mattias Rönnblom <mattias.ronnb...@ericsson.com> > --- > lib/eal/include/rte_common.h | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/lib/eal/include/rte_common.h > b/lib/eal/include/rte_common.h > index 4a399cc7c8..67587025ab 100644 > --- a/lib/eal/include/rte_common.h > +++ b/lib/eal/include/rte_common.h > @@ -222,6 +222,31 @@ static void > __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) > */ > #define __rte_noreturn __attribute__((noreturn)) > > +/** > + * Issue a warning in case the function's return value is ignored. > + * > + * The use of this attribute should be restricted to cases where > + * ignoring the marked function's return value is almost always a > + * bug. With GCC, some effort is required to make clear that ignoring > + * the return value is intentional. The usual void-casting method to > + * mark something unused as used does not suppress the warning with > + * this compiler. > + * > + * @code{.c} > + * __rte_warn_unused_result int foo(); > + * > + * void ignore_foo_result(void) { > + * foo(); // generates a warning with all compilers > + * > + * (void)foo(); // still generates the warning with GCC (but > not clang) > + * > + * int unused __rte_unused; > + * unused = foo(); // does the trick with all compilers > + * } > + * @endcode > + */ > +#define __rte_warn_unused_result __attribute__((warn_unused_result)) > + > /** > * Force a function to be inlined > */ > -- > 2.25.1 >
Nice! If only all functions were that well documented. :-) Reviewed-by: Morten Brørup <m...@smartsharesystems.com>
