In this recipe, we have not specified a directory where Fortran module files should be placed and we have kept this transparent. The location for module files can be specified by setting the CMAKE_Fortran_MODULE_DIRECTORY CMake variable. Note that it is also possible to set this as a target property, Fortran_MODULE_DIRECTORY, thus achieving a finer level of control. See https://cmake.org/cmake/help/v3.5/prop_tgt/Fortran_MODULE_DIRECTORY.html.