diff --git a/commands/umount/umount.c b/commands/umount/umount.c
index b65921631..6ec9e2da5 100644
--- a/commands/umount/umount.c
+++ b/commands/umount/umount.c
@@ -31,7 +31,7 @@ char *argv[];
 {
   int found;
   int umount_flags = 0UL;
-  char c;
+  int c;
   char *name;
 
   while ((c = getopt (argc, argv, "e")) != -1)