Nonexception

Nonexception is a term used in software engineering to describe an approach to error handling that avoids signaling errors via exceptions. In nonexception design, functions return values that indicate success or failure, often accompanied by explicit error data. The term is not a formal standard; it is used in discussions of exceptionless programming and in documenting language idioms that prefer explicit results over runtime unwinding.

Mechanisms include the use of result types or tuples, optional or union types that encode Ok/Err, and explicit propagation of errors through call chains. This contrasts with traditional exception-based control flow, where an error can unwind the call stack until caught.

Languages and ecosystems commonly associated with nonexception practices include Go, which returns a value and an error separately, and Rust, which uses the Result<T, E> type to encode success or failure without using exceptions. C and C-derived environments often rely on error codes or errno rather than exceptions. Some languages blend approaches, offering both straightforward results and exception mechanisms.

Advantages include predictable performance, easier static analysis, and control over resource cleanup. Disadvantages include boilerplate error propagation, potential for ignored errors, and sometimes reduced readability.

See also: exception handling; error handling; result type; error monad; exceptionless programming.