Informix Error -436

Reasons / Common Causes

-436 is the direct companion restriction to -435: whenever a bounded time-out value (0 or greater) is specified for the relevant ESQL/C or ESQL/COBOL mechanism, a callback function must also be supplied — the two arguments are required together, since the time-out is meaningless without a callback to invoke when it expires.

1. A bounded time-out value (0 or greater) supplied without a corresponding callback function — the direct, only cause.
2. Application code that sets a time-out defensively but forgets the callback, assuming a default no-op behavior exists when one doesn't.
3. Copy-pasted registration code missing the callback argument after being adapted from a different context.

Solutions / Resolution

1. Supply a valid callback function whenever a bounded time-out (0 or greater) is used, per the official guidance.
2. If no callback logic is actually needed, use -1 (indefinite wait) instead, per -435's guidance, rather than a bounded time-out with a missing callback.
3. Review the registration code for both arguments together — they're a package deal, not independently optional.

Examples

Supplying a callback alongside a bounded time-out

int timeout = 30;
/* register_callback is the actual function pointer required
   whenever timeout >= 0 */
/* pass both timeout and register_callback to the relevant
   ESQL/C registration call */

Using -1 instead, when no callback logic is needed

int timeout = -1;  /* indefinite wait; no callback required */

Diagnostic Checks

1. Check whether a callback function argument was actually supplied alongside a bounded time-out value.
2. Confirm whether a callback is genuinely needed, or whether -1 (indefinite wait) is actually the simpler, correct choice.

Related Errors / Related Topics

• -435 — "Time-out value must be -1 or greater." The closely related sibling restriction — together these two errors define the valid combinations for this time-out/callback mechanism.

Time-out and callback are supplied together or not at all — use -1 if no callback logic is actually needed, rather than a bounded time-out with a missing callback.