diff --git a/orte/mca/rml/oob/rml_oob_component.c b/orte/mca/rml/oob/rml_oob_component.c
index a7a914b94c..5f95326210 100644
--- a/orte/mca/rml/oob/rml_oob_component.c
+++ b/orte/mca/rml/oob/rml_oob_component.c
@@ -514,7 +514,7 @@ rml_oob_recv_route_callback(int status,
     ORTE_RML_OOB_MSG_HEADER_HTON(*hdr);
 
     /* NTH: fix potential race condition. oob may modify iov before the oob send completes */
-    new_iov = calloc (count, sizeof (struct iovec));
+    new_iov = (iovec*) calloc (count, sizeof (struct iovec));
     if (NULL == new_iov) {
 	opal_output (0, "%s:route_callback malloc error!", ORTE_NAME_PRINT(ORTE_PROC_MY_NAME));
         opal_backtrace_print(stderr);