Informix Error -649: The debug file name must be a NON-NULL CHAR or VARCHAR.

Reasons / Common Causes

-649 fires when SET DEBUG FILE TO's argument isn't a non-NULL character type — per the official guidance, the argument must be CHAR/VARCHAR.

1. A NULL value passed as the debug file name, per the official guidance — the argument must be non-NULL.
2. A non-character-typed value or variable passed, per the official guidance — a numeric or other non-CHAR/VARCHAR type given where a file name string is expected.

Solutions / Resolution

1. Supply a non-NULL CHAR/VARCHAR value for the debug file name, per the official guidance.
2. Check any variable used for the debug file name is both character-typed and confirmed non-NULL before the SET DEBUG FILE TO statement runs.

Examples

A NULL debug file name

DEFINE v_debug_path VARCHAR(200);
-- v_debug_path was never assigned a value; it's NULL
SET DEBUG FILE TO v_debug_path;
-- -649: v_debug_path is NULL

Corrected

DEFINE v_debug_path VARCHAR(200);
LET v_debug_path = '/path/to/debug/directory/routine_trace.out';
SET DEBUG FILE TO v_debug_path;

Diagnostic Checks

1. Confirm the value/variable supplied is CHAR/VARCHAR typed and has actually been assigned a non-NULL value before the SET DEBUG FILE TO statement executes.

Related Errors / Related Topics

• -648 — "Cannot open DEBUG file for SPL routine trace." A related SET DEBUG error, about the path's validity/permissions once a valid non-NULL character value has been supplied.

A type/nullability check on the argument itself — confirm it's a non-NULL CHAR/VARCHAR before troubleshooting the path further (that's -648's territory).