rb_str_update     774 include/ruby/intern.h void rb_str_update(VALUE, long, long, VALUE);
rb_str_update    2842 string.c           rb_str_update(str, 0L, 0L, str2);
rb_str_update    4243 string.c       #define rb_str_splice(str, beg, len, val) rb_str_update(str, beg, len, val)