A Study on the Effects of Exception Usage in Open-Source C++ Systems

Exception handling (EH) is a feature common to many modern programming languages, including C++, Java, and Python, that allows error handling in client code to be performed in a way that is both systematic and largely detached from the implementation of the main functionality. However, C++ developers sometimes choose not to use EH, as they feel that its use increases complexity of the resulting code: new control flow paths are added to the code, "stack unwinding'' adds extra responsibilities for the developer to worry about, and EH arguably detracts from the modular design of the system. In this thesis, we perform an exploratory empirical study of the effects of exceptions usage in 2721 open source C++ systems taken from GitHub. We observed that the number of edges in an augmented call graph increases, on average, by 22% when edges for exception flow are added to a graph. Additionally, about 8 out of 9 functions that may propagate a throw from another function. These results suggest that, in practice, the use of C++ EH can add complexity to the design of the system that developers must strive to be aware of

Making Exceptions on Exception Handling

Abstract—The exception-handling mechanism has been widely adopted to deal with exception conditions that may arise during program executions. To produce high-quality programs, developers are expected to handle these exception conditions and take necessary recovery or resource-releasing actions. Failing to handle these exception conditions can lead to not only performance degradation, but also critical issues. Developers can write formal specifications to capture expected exceptionhandling behavior, and then apply tools to automatically analyze program code for detecting specification violations. However, in practice, developers rarely write formal specifications. To address this issue, mining techniques have been used to mine common exception-handling behavior out of program code. In this paper, we discuss challenges and achievements in precisely specifying and mining formal exception-handling specifications, as tackled by our previous work. Our key insight is that expected exception-handling behavior may be “conditional ” or may need to accommodate “exceptional ” cases. I