diff --git a/include/boost/regex/pending/object_cache.hpp b/include/boost/regex/pending/object_cache.hpp
index bc37e276..2a7e00bc 100644
--- a/include/boost/regex/pending/object_cache.hpp
+++ b/include/boost/regex/pending/object_cache.hpp
@@ -119,7 +119,7 @@ boost::shared_ptr<Object const> object_cache<Key, Object>::do_get(const Key& k,
    //
    // Add it to the list, and index it:
    //
-   s_data.cont.push_back(value_type(result, 0));
+   s_data.cont.push_back(value_type(result, static_cast<Key const*>(0)));
    s_data.index.insert(std::make_pair(k, --(s_data.cont.end())));
    s_data.cont.back().second = &(s_data.index.find(k)->first);
    map_size_type s = s_data.index.size();