Returnkäsky

Returnkäsky is a term used in Finnish programming literature to refer to the return statement, a language construct that ends the execution of a function and yields a value to the caller.

The word is formed from the English word return and the Finnish käsky, meaning command. In programming, a returnkäsky transfers control back to the caller and, in many languages, supplies the function’s result via an accompanying expression.

The exact behavior of a returnkäsky depends on the programming language. In most languages, it terminates the current function. If the function has a declared return type, the expression following the return keyword must be compatible with that type; in void functions a bare return may be allowed to exit early. If no expression is provided, some languages return a default value (such as None or a void result), while others require an explicit value.

Syntax and rules vary across languages. In C-like languages, a function declared to return int might use return 5;, while in Python a function can end with return 5 or simply return to exit without a value. In languages with multiple return paths, the returnkäsky is a common mechanism for exiting early, often used for input validation or error handling.

Common considerations include ensuring a returnkäsky is present on all control paths in non-void functions, and avoiding unreachable code after a return. The concept is central to function semantics and data flow in many programming paradigms.

See also: return statement, function, control flow.