Report the user's preferred locale.

This returns an array of sdl.Locale objects, the final item zeroed out. When the caller is done with this array, it should call sdl.free() on the returned value; all the memory involved is allocated in a single block, so a single sdl.free() will suffice.

Returned language strings are in the format xx, where 'xx' is an ISO-639 language specifier (such as "en" for English, "de" for German, etc). Country strings are in the format YY, where "YY" is an ISO-3166 country code (such as "US" for the United States, "CA" for Canada, etc). Country might be nil if there's no specific guidance on them (so you might get { "en", "US" } for American English, but { "en", nil } means "English language, generically"). Language strings are never nil, except to terminate the array.

Please note that not all of these strings are 2 characters; some are three or more.

The returned list of locales are in the order of the user's preference. For example, a German citizen that is fluent in US English and knows enough Japanese to navigate around Tokyo might have a list like: { "de", "en_US", "jp", nil }. Someone from England might prefer British English (where "color" is spelled "colour", etc), but will settle for anything like it: { "en_GB", "en", nil }.

This procedure returns nil on error, including when the platform does not supply this information at all.

This might be a "slow" call that has to query the operating system. It's best to ask for this once and save the results. However, this list can change, usually because the user has changed a system preference outside of your program; SDL will send an sdl.LOCALECHANGED event in this case, if possible, and you can call this procedure again to get an updated copy of preferred locales.

Return array of locales, terminated with a locale with a nil language field. Will return nil on error.