rb_str_format     557 include/ruby/intern.h VALUE rb_str_format(int, const VALUE *, VALUE);
rb_str_format     421 sprintf.c          return rb_str_format(argc - 1, argv + 1, GETNTHARG(0));
rb_str_format    1131 string.c       	return rb_str_format(RARRAY_LEN(tmp), RARRAY_PTR(tmp), str);
rb_str_format    1133 string.c           return rb_str_format(1, &arg, str);