RocksSnapshot.cpp

rocksdb::Slice key1 = "1";
rocksdb::Slice key2 = "2";
std::string val1 = "one";
std::string val2 = "two";

// populate db first
db->Put(rocksdb::WriteOptions(), key1, val1);
db->Put(rocksdb::WriteOptions(), key2, val2);

rocksdb::ReadOptions readOptions;
readOptions.snapshot = db->GetSnapshot();
rocksdb::Iterator* it = db->NewIterator(readOptions);

// apply some updates to database
rocksdb::Slice key3 = "3";
std::string val3 = "three";
db->Put(rocksdb::WriteOptions(), key3, val3);

// read using iter to view the state when the snapshot was created
for (it->SeekToFirst(); it->Valid(); it->Next()) {
    cout << it->key().ToString() << ": " << it->value().ToString() << endl;
}
delete it;

// do not forget to release the snapshot
db->ReleaseSnapshot(readOptions.snapshot);