These things (Protobufs, Flatbuffers, Cereal, Cap'n Proto, Bond, Apache Avro, Thrift, MessagePack etc etc) are now a dime a dozen.
In fact, even if you want a C++-only solution like this, you're still spoiled for choice (any of Boost.Hana, Boost.Fusion, Cereal, or Boost.Serialization for reflection + a little code for binding to your choice of codec). Hopefully one day we'll get standardized compile-time reflection as a language feature.
Imho, code generators and schema files are a feature. If you don't care about forward or backward compatibility, or portability to other languages, then just avoid pointers and memcpy your structs to disk. There are even libraries like Boost.Interprocess that will help you do just that... even with complex multi-indexed data structures like hash tables and maps inside mmap()'d blocks.
That all said, these days I use Flatbuffers, because it's super efficient, header-only, round-trips to JSON, the code gen is tolerable, and it doesn't lead to executable size bloat.
Imho, code generators and schema files are a feature. If you don't care about forward or backward compatibility, or portability to other languages, then just avoid pointers and memcpy your structs to disk. There are even libraries like Boost.Interprocess that will help you do just that... even with complex multi-indexed data structures like hash tables and maps inside mmap()'d blocks.
That all said, these days I use Flatbuffers, because it's super efficient, header-only, round-trips to JSON, the code gen is tolerable, and it doesn't lead to executable size bloat.