diff --git a/aml/aml.c b/aml/aml.c
index 4b1c9c1..c7ae3cc 100644
--- a/aml/aml.c
+++ b/aml/aml.c
@@ -116,7 +116,7 @@ static void (*aml_handlers[256]) (int,void *,int); //pointers to user-provided A
 
 //internode comm (proc number X from each group)
 //intranode comm (all cores of one nodegroup)
-MPI_Comm comm, comm_intra;
+static MPI_Comm comm, comm_intra;
 
 // MPI stuff for sends
 static char *sendbuf; //coalescing buffers, most of memory is allocated is here