In C programming, an interface, often embodied by header files and function prototypes, defines a contract between different parts of a program or between a program and an external library. This contract specifies what functionality is available and how to access it. A violation of this contract occurs when the implementation deviates from the declared interface. For instance, if a header file declares a function to accept an integer argument, but the actual function definition expects a floating-point number, this constitutes a breach.
The integrity of these contracts is vital for maintaining code reliability and facilitating modular development. Strict adherence ensures that components can be modified or replaced without disrupting the functionality of other parts of the system. Historically, discrepancies between interface declarations and implementations have been a significant source of errors, leading to unpredictable program behavior and difficulties in debugging. Consistent and rigorous adherence to declared interfaces promotes code maintainability and reduces the likelihood of integration problems.
