Informix Error -684

Reasons / Common Causes

-684 fires when a routine is called in a context expecting a specific number of return values, but the routine's RETURNING clause declares more values than that context can accept — per the official guidance's example, a routine returning two values (INT, INT) called somewhere that expects only one.

1. A routine called inside an expression expecting a single scalar value, per the official guidance's example, when the routine's RETURNING clause declares more than one value.
2. A routine's RETURNING clause widened during editing (adding a return value) without checking every call site still matches the new count.
3. The wrong routine called by name, where a similarly-named routine with a different RETURNING arity was invoked by mistake.

Solutions / Resolution

1. Check the routine's RETURNING clause and compare its value count against the calling context's expectation.
2. Call the routine in a context that accepts all its declared return values, such as a multi-variable LET statement, if the values are genuinely all needed:

   LET v_total, v_count = get_order_totals(p_customer_id);
   

3. Or use only the specific value needed by wrapping the call appropriately, if the calling context genuinely only wants one of several returned values — Informix doesn't support discarding extra return values inline, so this typically means assigning to a full set of variables and using only the one needed afterward.

Examples

The disallowed mismatch

CREATE FUNCTION get_order_totals(p_customer_id INT)
  RETURNING INT, INT;  -- total, count
  ...
END FUNCTION;

SELECT get_order_totals(customer_id) FROM customers;
-- -684: get_order_totals returns 2 values, this context expects 1

Corrected — accept all declared values

DEFINE v_total, v_count INT;
LET v_total, v_count = get_order_totals(42);

Diagnostic Checks

1. Count the values in the routine's RETURNING clause and compare against how many the calling context (expression, LET, SELECT) actually expects.

Related Errors / Related Topics

• -655 — "RETURN value count does not match procedure declaration." A related return-count error, checked at the routine's own RETURN statement against its RETURNING declaration, rather than at a caller.
• -685 — "Function function-name returns too few values." The mirror-image situation: the caller expects more values than the routine returns.
• -686 — "Function function-name has returned more than one row." A related error, about returning multiple rows (via RETURN ... WITH RESUME) rather than too many values in one row.

Compare the routine's RETURNING clause's value count against what the specific call site actually expects — not every context accepts multiple return values.