The function set-locale-encodings
changes the default encodings used by those FLI functions and types which convert strings and characters and accept an :external-format
argument.
set-locale calls set-locale-encodings
after successfully setting the C locale.
convert-from-foreign-string
convert-to-foreign-string
:ef-mb-string
:ef-wc-string
set-locale
with-foreign-string
LispWorks Foreign Language Interface User Guide and Reference Manual - 29 Sep 2017