I posted about a week ago that I had some problems with asio and sending and receiving a line-based message protocol. I rewrote some parts of the code to clean it up and to see if there were any more errors hidden in the code duplications that were in there. I now don't get the truncated message mentioned before, but now it seems that some lines are lost completely. Setup: * Self-written server using boost::asio::read_until with '\n' as the delimiter. Works flawlessly even if there are multiple lines in the input... * Self-written client using async_write and a loop of io_service.run_one() and checking the resulting ec to enable timeouts. When the client uses normal GCC to compile, it works flawlessly, at least in my tests. But when I use MPI, especially the calls to MPI::Init() and MPI::Finalize() and comppile with mpic++ wrapper, some messages do not arrive at the server. The server is unchanged. The not-arriving messages use boost serialization for some data, but one message that uses it does get through. I have tried with openmpi and mpich2. I am now seriously out of ideas what else to try. Hannes