aliases may be used as command-line option names but the value is stored using the actual option name.
		By default this field is not defined.
	</dd>
	
	<dt><code><b>_badnumber</b></code></dt>
	<dd>
		String that defines the format of the error message generated when an command-line option cannot be converted to a number.
		The default value for this field is <code>"invalid value for option '%s', number excepted but got '%s'"</code>.
	</dd>
	
	<dt><code><b>_boolean</b></code></dt>
	<dd>
		Table that maps st