diff --git a/websockify/websockifyserver.py b/websockify/websockifyserver.py
index 01004cc..055bb12 100644
--- a/websockify/websockifyserver.py
+++ b/websockify/websockifyserver.py
@@ -684,13 +684,15 @@ class WebSockifyServer(object):
         original_signals = {
             signal.SIGINT: signal.getsignal(signal.SIGINT),
             signal.SIGTERM: signal.getsignal(signal.SIGTERM),
-            signal.SIGCHLD: signal.getsignal(signal.SIGCHLD),
         }
+        if getattr(signal, 'SIGCHLD', None) is not None:
+            original_signals[signal.SIGCHLD] = signal.getsignal(signal.SIGCHLD),
         signal.signal(signal.SIGINT, self.do_SIGINT)
         signal.signal(signal.SIGTERM, self.do_SIGTERM)
         # make sure that _cleanup is called when children die
         # by calling active_children on SIGCHLD
-        signal.signal(signal.SIGCHLD, self.multiprocessing_SIGCHLD)
+        if getattr(signal, 'SIGCHLD', None) is not None:
+            signal.signal(signal.SIGCHLD, self.multiprocessing_SIGCHLD)
 
         last_active_time = self.launch_time
         try: