-/* Copies the case that is CASE_IDX cases away from CW's tail
- into C. Returns true if successful, false on an I/O error or
- if CW is otherwise tainted. On failure, nullifies case C. */
-bool
-casewindow_get_case (const struct casewindow *cw_, casenumber case_idx,
- struct ccase *c)
+/* Returns the case that is CASE_IDX cases away from CW's tail
+ into C, or a null pointer on an I/O error or if CW is
+ otherwise tainted. The caller must call case_unref() on the
+ returned case when it is no longer needed. */
+struct ccase *
+casewindow_get_case (const struct casewindow *cw_, casenumber case_idx)