diff --git a/src/os/src/detail/osMem.c b/src/os/src/detail/osMem.c
index 1aee0813e7..93943c6543 100644
--- a/src/os/src/detail/osMem.c
+++ b/src/os/src/detail/osMem.c
@@ -13,6 +13,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#define _DEFAULT_SOURCE
 #include "os.h"
 #include "tulog.h"
 
diff --git a/src/os/src/detail/osTimer.c b/src/os/src/detail/osTimer.c
index 4074c50289..e0a2e90314 100644
--- a/src/os/src/detail/osTimer.c
+++ b/src/os/src/detail/osTimer.c
@@ -13,6 +13,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#define _DEFAULT_SOURCE
 #include "os.h"
 #include "taosdef.h"
 #include "tglobal.h"