Resolves the effective locale for a CupThreadProvider-level locale input.
Resolution order:
An explicit locale tag other than 'auto' — used verbatim (e.g. 'ja',
'zh-Hans'), so an in-app language picker keeps working.
'auto' or omitted — the detected device locale from
getDeviceLocale.
'en' when nothing is detectable.
The returned tag is a raw locale identifier (not normalized to a dictionary
key); feed it to getLocaleStrings, whose BCP 47 prefix matching
already handles regional variants like pt-BR, zh-Hans-CN, or nb-NO.
Resolves the effective locale for a CupThreadProvider-level
localeinput.Resolution order:
'auto'— used verbatim (e.g.'ja','zh-Hans'), so an in-app language picker keeps working.'auto'or omitted — the detected device locale from getDeviceLocale.'en'when nothing is detectable.The returned tag is a raw locale identifier (not normalized to a dictionary key); feed it to getLocaleStrings, whose BCP 47 prefix matching already handles regional variants like
pt-BR,zh-Hans-CN, ornb-NO.