Very good questions - in ten years no one has asked this.
Oh :-(
Title almost says it all, how do you verify that your classes serialization code is truly platform independent,
This would not apply to binary archives as these are not guarenteed to be portable.
The case were archives are created on one platform and loaded on another is not explicitly tested.
and doesn't accidently break later?
Hmmm I'm not sure how one could test that things aren't going to break later.
Allow me to explain - I've experimented with adding serialization support to Boost.Multiprecision - amounst other things this would allow those types to be used with MPI for massively parrellel applications (but I digress). Now, binary archives are no issue, a simple loopback test is enough. But since I know the internals of the classes are platform specific, I've had to come up with a serialization format (for cpp_int for example) which is platform independent. Or at least I think it is. I tend to assume that anything not tested doesn't work. Maybe I'll just create some sample archives on 32 and 64 bit platforms and try reading them. John.