the arguments of printf-like functions. This is done by a macro. */
#if defined(__GNUC__) || defined(__clang__)
-# define PRINTF_FUNCTION(A,B) __attribute__((format(printf,A,B)))
-# define ARG_UNUSED __attribute__((__unused__))
+# define PRINTF_FUNCTION(A,B) __attribute__((format(printf,A,B)))
+# define ARG_UNUSED __attribute__((__unused__))
+# define WARN_UNUSED_RESULT __attribute__((__warn_unused_result__))
#else
# define PRINTF_FUNCTION(A,B)
# define ARG_UNUSED /**/
+# define WARN_UNUSED_RESULT /**/
#endif
#ifdef WANT_DEEPER_PRINTF_CHECKS