diff --git a/src/ip.cpp b/src/ip.cpp
index 59720827..9b505798 100644
--- a/src/ip.cpp
+++ b/src/ip.cpp
@@ -129,7 +129,8 @@ void zmq::enable_ipv4_mapping (fd_t s_)
 {
     LIBZMQ_UNUSED (s_);
 
-#if defined IPV6_V6ONLY && !defined ZMQ_HAVE_OPENBSD && !defined ZMQ_HAVE_DRAGONFLY
+#if defined IPV6_V6ONLY && !defined ZMQ_HAVE_OPENBSD                           \
+  && !defined ZMQ_HAVE_DRAGONFLY
 #ifdef ZMQ_HAVE_WINDOWS
     DWORD flag = 0;
 #else