Abstract Similar to software systems, programming languages evolve substantially over time. Indeed, the community has more recently seen the release of new versions of mainstream languages in shorter and shorter time frames. For instance, the C++ working group has begun to release a new version of the language every 3 years, which now has a greater number of modern C++ features and improvements in modern standards (C++11, C++14, C++17, and C++ 20). Nonetheless, there is little empirical evidence on how developers are transitioning to use modern C++ constructs in legacy systems, and not understanding the trends and reasons for adopting these new modern C++ features might hinder software developers in conducting rejuvenation efforts. In this paper, we conduct an in‐depth study to understand the development practices of KDE contributors to evolve their projects toward the use of modern C++ features. Our results show a trend in the widespread adoption of some modern C++ features (lambda expressions, auto‐typed variables, and range‐based for) in KDE community projects. We also found that developers in the KDE community are making large efforts to modernize their programs using automated tools, and we present some modernization scenarios and the benefits of adopting modern C++ features of the C++ programming language. Our results might help C++ software developers, in general, to evolve C++ legacy systems and tools builders to implement more effective tools that could help in rejuvenation efforts.

Exception handling (EH) is a well-known mechanism that aims at improving software reliability in a modular way - allowing a better separation between the code that deals with exceptional conditions and the code that deals with the normal control flow of a program. Although the exception handling mechanism was conceived almost 40 years ago, formulating a reasonable design of exception handling code is still considered a challenge, which might hinder its widespread use. This paper reports the results of an empirical study that use a mixed-method approach to investigate the adoption of the exception handing mechanism in C++. Firstly, we carried out a static analysis investigation to understand how developers employ the exception handling construct of C++, considering 65 open-source systems (which comprise 34 million lines of C++ code overall). Then, to better understand the findings from the static analysis phase, we conducted a survey involving 145 C++ developers who have contributed to the subject systems. Some of the findings consistently detected during this mixed-method study reveal that, for several projects, the use of exception handling constructs is scarce and developers favor the use of other strategies to deal with exceptional conditions. In addition, the survey respondents consider that incompatibility with existing C code and libraries, extra performance costs (in terms of response time and size of the compiled code), and lack of expertise to design an exception handling strategy are among the reasons for avoiding the use of exception handling constructs.