-typedef void (*converter)(const char *arg, void *result);
-
-static void multiconvert(const char *arg, void *result, converter convert)
+/* A note on bad input: neither bash 3.2 nor coreutils 6.10 stop on it.
+ * They report it:
+ * bash: printf: XXX: invalid number
+ * printf: XXX: expected a numeric value
+ * bash: printf: 123XXX: invalid number
+ * printf: 123XXX: value not completely converted
+ * but then they use 0 (or partially converted numeric prefix) as a value
+ * and continue. They exit with 1 in this case.
+ * Both accept insane field width/precision (e.g. %9999999999.9999999999d).
+ * Both print error message and assume 0 if %*.*f width/precision is "bad"
+ * (but negative numbers are not "bad").
+ * Both accept negative numbers for %u specifier.
+ *
+ * We try to be compatible.
+ */
+
+typedef void FAST_FUNC (*converter)(const char *arg, void *result);
+
+static int multiconvert(const char *arg, void *result, converter convert)