Informix Error -840

-840 Name is too long.

Names of databases, reports, forms, and other files must be 10 characters or shorter. Select a new, shorter name, and repeat this operation. In DOS systems, filenames can be a maximum of 8 characters plus a 3-character extension.

Oninit® Troubleshooting Guidance

Reasons / Common Causes

-840 fires when a name for a database, report, form, or other file exceeds the interactive tool's length limit — per the official guidance, 10 characters, with a stricter 8+3 DOS filename limit on that specific platform.

A name longer than 10 characters, per the official guidance — the direct, general limit.
On DOS specifically, a name exceeding the 8-character-plus-3-character-extension limit, per the official guidance — a platform-specific, stricter constraint.

Solutions / Resolution

Select a new, shorter name, per the official guidance, within the 10-character limit (or the DOS 8+3 limit on that platform).
Repeat the operation with the corrected name, per the official guidance.

Examples

Shortening a name to fit the limit

report_summary_2025  -- 20 characters, too long
rptsum25             -- 8 characters, fits

Diagnostic Checks

Count the name's characters against the 10-character limit (or 8+3 on DOS).

Related Errors / Related Topics

-841 — "Name must start with a letter or "" and contain letters, digits, or ""." A related naming-rule restriction, on character composition rather than length.

A 10-character limit (8+3 on DOS specifically) for these interactive-tool object names.