1. The default locale directory is used if the localedir parameter is NULL. The current working directory will be used if the resulting locale directory is NULL.

2. The domain name name is used to build file names of message catalogs. For instance the message catalog for domain "mosel", language "es" in the locale directory "/usr/share/locale" is "/usr/share/locale/es/LC_MESSAGES/mosel.mo"

3. Message catalogs are opened when the first XNLSgettext call is issued, not at the time of opening the domain.

4. The same domain context will be returned if a given domain name is open several times (the localedir parameter is ignored when the domain is already open). The system keeps track of the number of times each domain context has been returned and requires an equal number of calls to XNLSclosemsgdom to release properly the resources associated with the domain.