diff --git a/src/ffi/mod.rs b/src/ffi/mod.rs
index bc353a9a8a7bcd86aac1fb1ee11d230c8c2ef012..dd5ee15d4dd7174dd70897fa897b263157a6ee59 100644
--- a/src/ffi/mod.rs
+++ b/src/ffi/mod.rs
@@ -208,8 +208,12 @@ pub unsafe extern "C" fn connector_add_port_pair(
     out_getter: *mut PortId,
 ) {
     let [o, i] = connector.new_port_pair();
-    out_putter.write(o);
-    out_getter.write(i);
+    if !out_putter.is_null() {
+        out_putter.write(o);
+    }
+    if !out_getter.is_null() {
+        out_getter.write(i);
+    }
 }
 
 /// Given