Recently, concolic testing has drawn a lot of attention from the research community as a practical solution of overcoming limitations of manual test case generation. CONBOL, a concolic testing framework for large-scale embedded industrial software, has shown effectiveness of discovering real defects even for commercial quality software. In this paper, we extend CONBOL to be applicable to a project written in C++. Front-end of CONBOL is re-implemented based on LLVM and concolic engine is also modified. We design an enhanced DFS search strategy to enlarge search space when there an infinite loop exists in the execution path or control flow is too complex to be traversed. After applying to real world project, we prove that enhanced search strategy is better to increase test coverage. Finally, we investigate reasons of segmentation faults during concolic execution and suggest several heuristics to decrease segmentation faults.