diff --git a/os/os-linux.h b/os/os-linux.h
index 828b208..9f547ff 100644
--- a/os/os-linux.h
+++ b/os/os-linux.h
@@ -92,8 +92,8 @@
 	sched_getaffinity((pid), (ptr))
 #endif
 
-#define fio_cpu_clear(mask, cpu)	CPU_CLR((cpu), (mask))
-#define fio_cpu_set(mask, cpu)		CPU_SET((cpu), (mask))
+#define fio_cpu_clear(mask, cpu)	(void) CPU_CLR((cpu), (mask))
+#define fio_cpu_set(mask, cpu)		(void) CPU_SET((cpu), (mask))
 
 static inline int fio_cpuset_init(os_cpu_mask_t *mask)
 {