diff --git a/src/lib/asiolink/unix_domain_socket.h b/src/lib/asiolink/unix_domain_socket.h
index 03b3c6201c..7c669d7eda 100644
--- a/src/lib/asiolink/unix_domain_socket.h
+++ b/src/lib/asiolink/unix_domain_socket.h
@@ -33,7 +33,7 @@ public:
     ///
     /// @param io_service Reference to IOService to be used by this
     /// class.
-    UnixDomainSocket(IOService& io_service);
+    explicit UnixDomainSocket(IOService& io_service);
 
     /// @brief Returns native socket representation.
     virtual int getNative() const;