* PARSE_OPT_NONEG: says that this option cannot be negated
* PARSE_OPT_HIDDEN: this option is skipped in the default usage, and
* shown only in the full usage.
- * PARSE_OPT_LASTARG_DEFAULT: if no argument is given, the default value
- * is used.
+ * PARSE_OPT_LASTARG_DEFAULT: says that this option will take the default
+ * value if no argument is given when the option
+ * is last on the command line. If the option is
+ * not last it will require an argument.
+ * Should not be used with PARSE_OPT_OPTARG.
* PARSE_OPT_NODASH: this option doesn't start with a dash.
* PARSE_OPT_LITERAL_ARGHELP: says that argh shouldn't be enclosed in brackets
* (i.e. '<argh>') in the help message.