--- lang/cpp/src/keylistresult.cpp
+++ lang/cpp/src/keylistresult.cpp
@@ -77,7 +77,7 @@
 
 void GpgME::KeyListResult::detach()
 {
-    if (!d || d.unique()) {
+    if (!d || d.use_count() == 1) {
         return;
     }
     d.reset(new Private(*d));