diff --git a/test/test_arc4random.c b/test/test_arc4random.c
index 5399e90bb403e1582309cd9907adf1eef383cad0..724d6f7f26ea2e02496eaf2c0df80e03d4e5a888 100644
--- a/test/test_arc4random.c
+++ b/test/test_arc4random.c
@@ -64,7 +64,7 @@ bench(int fd, size_t siz, size_t niter)
         s0 = sys_cpu_timestamp();
         arc4random_buf(buf, siz);
         s1 = sys_cpu_timestamp();
-        m  =  read(fd, buf, siz);
+        m  =  read(fd, buf, siz); (void) m;
         s2 = sys_cpu_timestamp();
 
         ta += s1 - s0;