@han190 Thanks a lot, I was not aware of the response file possibility in fpm yet. However,how the selection via response file choice can be propagated between projects? My project with optional coarray components is a library. How does an other project, which uses my library as a dependency, specifies, that it wishes to use the my library with or without coarray support? (It is important to allow the consumers to opt-out for mpi and coarray support, as they might not have the right environment for those at all.)