diff --git a/ffserver.c b/ffserver.c
index ccb5c0ab5c310473a77d069a7a5324e00e45362e..400009ac69a8f2733637b28765bf459c27f1b3eb 100644
--- a/ffserver.c
+++ b/ffserver.c
@@ -19,6 +19,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#define _XOPEN_SOURCE 600
+
 #include "config.h"
 #ifndef HAVE_CLOSESOCKET
 #define closesocket close