diff --git a/libcutils/android_reboot.c b/libcutils/android_reboot.c
index aa86206..6ae23c1 100644
--- a/libcutils/android_reboot.c
+++ b/libcutils/android_reboot.c
@@ -89,7 +89,7 @@
 }
 
 
-int android_reboot(int cmd, int flags UNUSED, char *arg)
+int android_reboot(int cmd, int flags UNUSED, const char *arg)
 {
     int ret;