diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index e9a247256..da600f2dc 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -842,18 +842,8 @@ class sun_name_t
       /* Allows 108 bytes sun_path plus trailing NUL */
       char _nul[sizeof (struct sockaddr_un) + 1];
     };
-  sun_name_t ()
-    {
-      un_len = 0;
-      un.sun_family = 0;
-      _nul[sizeof (struct sockaddr_un)] = '\0';
-    }
-  sun_name_t (const struct sockaddr *name, __socklen_t namelen)
-    {
-      un_len = namelen < (__socklen_t) sizeof un ? namelen : sizeof un;
-      memcpy (&un, name, un_len);
-      _nul[sizeof (struct sockaddr_un)] = '\0';
-    }
+  sun_name_t ();
+  sun_name_t (const struct sockaddr *name, __socklen_t namelen);
 
   void *operator new (size_t) __attribute__ ((nothrow))
     { return cmalloc_abort (HEAP_FHANDLER, sizeof (sun_name_t)); }
diff --git a/winsup/cygwin/fhandler_socket_unix.cc b/winsup/cygwin/fhandler_socket_unix.cc
index 36a3cb3c4..f93b91221 100644
--- a/winsup/cygwin/fhandler_socket_unix.cc
+++ b/winsup/cygwin/fhandler_socket_unix.cc
@@ -69,6 +69,23 @@ GUID __cygwin_socket_guid = {
   .Data4 = { 0xba, 0xb3, 0xc5, 0xb1, 0xf9, 0x2c, 0xb8, 0x8c }
 };
 
+sun_name_t::sun_name_t ()
+{
+  un_len = sizeof (sa_family_t);
+  un.sun_family = AF_UNIX;
+  _nul[sizeof (struct sockaddr_un)] = '\0';
+}
+
+sun_name_t::sun_name_t (const struct sockaddr *name, socklen_t namelen)
+{
+  if (namelen < 0)
+    namelen = 0;
+  un_len = namelen < (__socklen_t) sizeof un ? namelen : sizeof un;
+  if (name)
+    memcpy (&un, name, un_len);
+  _nul[sizeof (struct sockaddr_un)] = '\0';
+}
+
 HANDLE
 fhandler_socket_unix::create_abstract_link (const sun_name_t *sun,
 					    PUNICODE_STRING pipe_name)