I've been looking around for a while for syncable database solutions, i.e. store data locally and then replicate it to a server when there is a network connection available. The end purpose is so that a user can edit data on one device and then see it on another once they've both been synced. This brings up the issue of conflicts e.g. if a user edits the same data on different devices while both offline and then both go online.
The best solution I've found so far is Couchbase Lite (http://developer.couchbase.com/mobile/get-started/couchbase-lite-overview/index.html), which is a multi-platform library that covers all of that ground. The drawback is that requires cross-language code as each platform has a different package (i.e. Android Java, iOS/OSX obj-C, Windows C#...) - there is no C++ library.
Before I start write all the bridge code, I wanted to see if there are any C/C++ options that would get me there. A possible contender I've found is LevelDB (http://leveldb.org) which is pretty bare bones, and although there are a lot of addons in Node.js including https://github.com/hij1nx/level-replicator, I couldn't find anything in C++.
Anyone know of any other solutions?