diff --git a/src/os_vms.c b/src/os_vms.c
index 96fbc17..b8ad788 100644
--- a/src/os_vms.c
+++ b/src/os_vms.c
@@ -112,7 +112,7 @@
 }
 
     void
-mch_settmode(int tmode)
+mch_settmode(tmode_T tmode)
 {
     int	status;