1 files changed, 7 insertions, 3 deletions
diff --git a/src/Write2D.c b/src/Write2D.c
index 2906c79..5681f7d 100644
--- a/src/Write2D.c
+++ b/src/Write2D.c
@@ -113,9 +113,13 @@ int IOSDF_Write2D (const cGH *GH, int vindex, const char *alias)
   maxdir = gdata.dim == 2 ? 1 : 3;
 
   /* get the coordinate system associated with this grid variable */
-  groupname = CCTK_GroupName (gindex);
-  coord_system_handle = Coord_GroupSystem (GH, groupname);
-  free (groupname);
+  coord_system_handle = -1;
+  if (CCTK_IsFunctionAliased ("Coord_GroupSystem"))
+  {
+    groupname = CCTK_GroupName (gindex);
+    coord_system_handle = Coord_GroupSystem (GH, groupname);
+    free (groupname);
+  }
 
   dir = gdata.dim < 3 ? gdata.dim : 3;