errorvalue

An errorvalue is a special value produced by a computation to indicate that the expression could not be evaluated as intended. It serves as a signal that an error condition occurred and that the resulting value should not be treated as a valid result. Error values are used across different computing contexts to distinguish normal outputs from failure cases.

In spreadsheets, error values are commonly exposed as visible markers. For example, Microsoft Excel uses several built-in error values such as #DIV/0! for division by zero, #N/A for unavailable data, #VALUE! for an invalid argument type, #REF! for a broken reference, #NAME? for an unrecognized symbol, #NUM! for an invalid numeric result, and #NULL! for an intersection that yields no data. These values propagate through formulas unless explicitly handled.

In programming, error values can be returned, wrapped in error objects, or indicated by sentinel values like null, None, or a dedicated error code. Depending on the language, they may propagate automatically or require explicit handling via conditional logic, exceptions, or result types (for example, Ok/Err or Result types). The use of error values aims to separate normal results from failure information without necessarily interrupting control flow.

Handling approaches vary: defensive checks after operations, type-safe result envelopes, or exception handling mechanisms. Design considerations include ensuring error values are distinguishable from valid results, providing meaningful error information, and avoiding silent failures. In modern practice, many languages favor explicit error signaling and structured handling (such as option/maybe or result types) to improve reliability and readability.