Hello, I'm using the class mapped_file from boost/iostreams to read and write to a file. I stumbled across a persistency-question which I couldn't answer from the documentation. When I'm using a normal c++ ofstream, I can be sure that after I called flush(), that the data is written to disk, even if my program crashes afterwards. But what if I'm using a mapped_file, is there any way to ensure that the written data will reach the disc, even if my program crashes at some later point? Thanks a lot for your help in advance. Best regards Florian