--- a/upmpd/upmpdutils.hxx
+++ b/upmpd/upmpdutils.hxx
@@ -62,6 +62,13 @@
extern std::string regsub1(const std::string& sexp, const std::string& input,
const std::string& repl);
+// Return map with "newer" elements which differ from "old". Old may
+// have fewer elts than "newer" (e.g. may be empty), we use the
+// "newer" entries for diffing
+extern std::unordered_map<std::string, std::string>
+diffmaps(const std::unordered_map<std::string, std::string>& old,
+ const std::unordered_map<std::string, std::string>& newer);
+
/// Lock/pid file class. From Recoll
class Pidfile {
public: