interlocked

Interlocked is an adjective and noun used to describe components or systems that are connected in such a way that the state or action of one part prevents or enables another. The concept emphasizes mutual dependence to ensure safety, correct sequencing, or atomicity in operations. Interlocking can be mechanical, electrical, electronic, or software-based, and it is employed to secure correct functioning in complex apparatus.

In safety engineering, interlocks are devices designed to prevent operation until certain conditions are met. Examples include door interlocks that keep equipment guarded while it is active, and interlock switches that must be satisfied before power can be applied. Mechanical interlocks may physically block movement, while electrical interlocks rely on circuits or signaling to enforce safe states.

In railway signaling, an interlocking system prevents conflicting movements by locking together the settings of signals, route switches (points), and related devices. By ensuring that only a safe, non-conflicting combination of indications can be set, interlockings reduce the risk of accidents. Modern interlockings are electronic or computer-based, though some older installations are mechanical.

In computing, interlocked operations refer to atomic actions that execute without interruption, used to avoid race conditions in multithreaded environments. The term is associated with APIs such as the Interlocked class in the .NET framework, which provides atomic operations like Increment, Decrement, CompareExchange, and Exchange. Similar atomic primitives appear in many languages to support lock-free synchronization.

Overall, interlocking describes a design principle where states or actions are deliberately constrained to maintain safe, correct, or predictable behavior across systems.