C++ project has a possibility to manage build configurations (Project | Properties | C/C++ Build). You can add your custom build configuration with different preprocessor symbols defined. One configuration is the active one. This is not possible with the current Qt Project - you define preprocessor symbols in *.pro file - whenever you want to build Qt Project with different set of defines you need to modify your pro file. You cannot just simply activate different build configuration and just build (without modifying the source pro file)