rb_str_encode     218 include/ruby/encoding.h VALUE rb_str_encode(VALUE str, VALUE to, int ecflags, VALUE ecopts);
rb_str_encode     875 io.c                       str = rb_str_encode(str, common_encoding,
rb_str_encode    4889 io.c           	    fname = rb_str_encode(fname, fs_enc, 0, Qnil);
rb_str_encode    3732 transcode.c        string = rb_str_encode(string, rb_enc_from_encoding(rb_enc_find(insert_enc)), 0, Qnil);