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 NULL if there's
no specific guidance on them (so you might get { "en", "US" } for American English, but { "en", NULL }
means "English language, generically"). Language strings are never NULL, 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", NULL }. Someone from England might prefer British English (where "color" is spelled
"colour", etc), but will settle for anything like it: { "en_GB", "en", NULL }.
This function returns NULL 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_EVENT_LOCALE_CHANGED
event in this case, if possible, and you can call this function again to get an updated copy of
preferred locales.