diff --git a/cpp/exports.hpp b/cpp/exports.hpp
index 5ffee273d0ffcfd4d78c849830e69d484b1e361f..261f9fda3374aeb1ea5e43aabaebbefda9cedfcb 100644
--- a/cpp/exports.hpp
+++ b/cpp/exports.hpp
@@ -24,6 +24,12 @@ std::ostream &operator<<(std::ostream &s, const Graph &g) {
     return s;
 }
 
+template <class T1, class T2>
+std::ostream &operator<<(std::ostream &s, const std::pair<T1, T2>& p) {
+    s << '{' << p.first << ',' << p.second << '}';
+    return s;
+}
+
 template <typename FwdIterator>
 std::ostream& output_array(std::ostream& s, FwdIterator begin,
                            FwdIterator end) {