This question and answers to it reassure me that STXXL handles only fixed data length. Are there any alternatives to STXXL to handle dynamic data size (data size unknown at compile time)?
Or are there any tricks to use STXXL to handle dynamic data size? The above link mentioned defining a number of structures of varying lengths and picking the closest at run-time. I have been considering creating a tool to detect data size or to get the user specified record size, then let the tool automatically generate code using the known size, compile it to another executable, and run it.