status = doc:UseJPEncodings()
doc:UseJPEncodings() enables Japanese encodings. After doc:UseJPEncodings() is invoked, an application can use the following Japanese encodings:
When doc:UseJPEncodings() succeeds, it returns #HPDF_OK. Otherwise, it returns an error code and the error handler is invoked.
#HPDF_INVALID_DOCUMENT - An invalid document handle was set.
#HPDF_FAILED_TO_ALLOC_MEM - Memory allocation failed.
#HPDF_DUPLICATE_REGISTRATION - The encoding of the same name has already been registered.