David Abrahams wrote:
Peter Dimov wrote:
In the situations that I've needed it, the subset of types that could be written in a single operation could not be described by a type trait. A type trait can't tell you whether the in-memory representation and the on-disk representation of a type are the same.
As soon as you talk about "on-disk" you're already limiting your thinking too much, since we're not necessarily serializing to disk, and the idea of having the "same representation" somewhere is somewhat limiting too. An MPI archive builds up a skeletal representation of what needs to be serialized and then MPI reads it out of memory into the hardware.
For example, MPI archives support array serialization for all PODs that are not pointers and do not contain pointer members.
I'm not sure I follow. How does an MPI archive serialize an array of X, where X is an arbitrary POD (without pointer members)?