Interface type checking of large C applications

Compare is a program that exposes inconsistencies between the declaration and invocation of functions written in the C language. Such a tool is not needed when the application program is contained in a single source file, since the compiler will easily detect such mismatches. But in large applications, the cost of performing interface type checks using traditional analysis tools can become more expensive than many programmers are willing to accept. Compare is intended to address the problem of checking interfaces for very large C applications. Compare relies on a preprocessor that extracts information concerning interfaces external to each file in an application. This preprocessor can itself become expensive to run, but its output is used for many different tasks in the development process; hence, the cost is amortized over many useful activities. The Compare program operates on just the extracted information, and it therefore very inexpensive to utilize. Moreover, as we will show this approach is able to detect some parameter mismatches that existing analysis tools miss.