diff --git a/src/collection/backend/lmdb.h b/src/collection/backend/lmdb.h
index 85f104a6..41f9d5c8 100644
--- a/src/collection/backend/lmdb.h
+++ b/src/collection/backend/lmdb.h
@@ -16,6 +16,7 @@
 
 #ifdef __cplusplus
 #include <string>
+#include <cstring>
 #include <iostream>
 #include <unordered_map>
 #include <list>