If the Visual Studio settings are set properly, it is not necessary to include precompiled_header.hpp in each .cpp file. Visual Studio will pass /FI precompiled_hearder.hpp to MSVC, which includes precompiled_header.hpp automatically (see https://docs.microsoft.com/en-us/cpp/build/reference/fi-name-forced-include-file for more details). You still need precompiled_header.cpp, but it can be empty.