set_option_encoding_once  655 ruby.c             set_option_encoding_once("default_intenal", &opt->intern.enc.name, e, elen)
set_option_encoding_once  657 ruby.c             set_option_encoding_once("default_extenal", &opt->ext.enc.name, e, elen)
set_option_encoding_once  659 ruby.c             set_option_encoding_once("source", &opt->src.enc.name, e, elen)