diff --git a/src/eval.c b/src/eval.c
index b68fcfd..a950436 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -10503,8 +10503,9 @@
 	    part = PART_IN;
 	else
 	    part = PART_SOCK;
-	if (channel->ch_part[part].ch_buffer != NULL)
-	    rettv->vval.v_number = channel->ch_part[part].ch_buffer->b_fnum;
+	if (channel->ch_part[part].ch_bufref.br_buf != NULL)
+	    rettv->vval.v_number =
+			      channel->ch_part[part].ch_bufref.br_buf->b_fnum;
     }
 }