On Thu, 21 Jun 2007 11:55:30 -0700, Robert Ramey <ramey@rrsd.com> wrote:
Sohail Somani wrote:
On Thu, 2007-21-06 at 17:56 +0000, Jared McIntyre wrote:
I changed ARCHIVE_VERSION in basic_archive.cpp to 3 (from 4) and this worked for me. Luckily, I'm not using any collections whose serialization format has changed.
Even if you are, shouldn't it be class_version that matters *not* the serialization library version?
a subtle but important distinction.
versions numbers are generally attributes of the class definition/declaration.
Including version information with class serialzation can include a small performance penalty and I thought it reasonable for STL serialization to never change (silly me). So I left the STL serializations unversioned.
When it came time to change the STL serializations - I had to bump the "global" library version and use that number to branch code.
It might be worth sharing my experience with this change in version number. Our product has its own saved files, which are themselves versioned. The mechanism for doing this is as old as C++ and is very intrusive. I came up with a mechanism to embed boost::serialization output in our saved files. Very very slick. Good job, by the way. When I upgraded to 1.34.0, some of our tests started to silently fail. Surprisingly, there was no crash, and we attributed the differences to something else entirely. It took a bit of effort to realize the values were not restoring the same as before. When we determined it was a serialization issue, I immediately looked in the documentation for any notes about breaking changes. I searched the mailing list for references. Nothing helped. I then stepped through the code to determine what changed, which revealed the item_version (if I remember correctly) change which was bracketed by a boost archive version check. The fix was fairly straight-forward. Since we have our own version numbers, I merely created a mapping of our versions to boost archive versions. I also added some code that will immediately crash the application as soon as the boost version is incremented again so the developer knows to update the mapping and bump our version number. All's well that ends well, but some more information up front would have helped me track this down faster. Jeff Faust