-unsigned int _gen_result(int, const char *, char *, unsigned int, char *, ...);
+#ifdef __MINGW_PRINTF_FORMAT
+# define TAP_PRINTF_FORMAT __MINGW_PRINTF_FORMAT
+#else
+# define TAP_PRINTF_FORMAT printf
+#endif
+
+__attribute__((format(TAP_PRINTF_FORMAT, 5, 6)))
+unsigned int _gen_result(int, const char *, const char *, unsigned int, const char *, ...);