- * If @string is equal to "all", all flags are set. If @string
- * is equal to "help", all the available keys in @keys are printed
- * out to standard error.
+ * If @string is equal to "all", all flags are set. Any flags
+ * specified along with "all" in @string are inverted; thus,
+ * "all,foo,bar" or "foo,bar,all" sets all flags except those
+ * corresponding to "foo" and "bar".
+ *
+ * If @string is equal to "help", all the available keys in @keys
+ * are printed out to standard error.