By default, the OnixS C++ FIX Engine stores all incoming and outgoing messages, session state data as well as the Engines primary log in files in MsgStorage subfolder of the current folder for the application executing FIX Engine.

However, it is possible to store all session-related logging data in memory. For these purposes, storageType parameter of OnixS::FIX::Session::Session constructor is available. Once OnixS::FIX::Session::MemoryBasedStorage value will be specified as value for the storageType parameter, session-related data will be logged into memory.