rb_enc_set_index  616 encoding.c         rb_enc_set_index(obj, idx);
rb_enc_set_index   32 include/ruby/encoding.h         rb_enc_set_index(rb_encoding_set_obj, encoding_set_enc_index); \
rb_enc_set_index   75 include/ruby/encoding.h void rb_enc_set_index(VALUE obj, int encindex);
rb_enc_set_index 1030 pack.c         	rb_enc_set_index(res, rb_utf8_encindex());
rb_enc_set_index  278 string.c           rb_enc_set_index(str1, ENCODING_GET(str2));