+An earlier version of this document stated that @code{value_len} was
+repeated before each of the missing values, so that there was an extra
+@code{int32} value of 8 before each missing value after the first.
+Old versions of PSPP wrote data files in this format. Readers can
+tolerate this mistake, if they wish, by noticing and skipping the
+extra @code{int32} values, which wouldn't ordinarily occur in strings.
+