diff --git a/tests/zfs-tests/cmd/clonefile.c b/tests/zfs-tests/cmd/clonefile.c
index d002cd9b58..bc30bb7798 100644
--- a/tests/zfs-tests/cmd/clonefile.c
+++ b/tests/zfs-tests/cmd/clonefile.c
@@ -162,7 +162,7 @@ main(int argc, char **argv)
 {
 	cf_mode_t mode = CF_MODE_NONE;
 
-	char c;
+	int c;
 	while ((c = getopt(argc, argv, "crfdq")) != -1) {
 		switch (c) {
 			case 'c':