implementation-defined
Computing term used in specifications (e.g., programming language standards) to indicate that the behavior depends on the particular compiler or runtime environment, and must be documented by the implementer.
In C, whether character types are signed is implementation-defined.
This behavior is implementation-defined, so it is better not to rely on it in portable code.
未定義動作 (undefined behavior) is stronger: the standard imposes no requirements and anything can happen. 処理系定義 requires the implementation to choose and document a specific behavior.
実装依存 (implementation-dependent) is a looser, more general term. 処理系定義 is the formal term used in language standards.
implementation-defined behavior
Compound of 処理系 (implementation, processing system) and 定義 (definition). A direct translation of the English computing term 'implementation-defined'.