diff --git a/apps/s_server.c b/apps/s_server.c
index 14dd8a69d..8645c6c20 100644
--- a/apps/s_server.c
+++ b/apps/s_server.c
@@ -2014,7 +2014,7 @@ static void wait_for_async(SSL *s)
     fd_set asyncfds;
 
     fd = SSL_get_async_wait_fd(s);
-    if (!fd)
+    if (fd < 0)
         return;
 
     width = fd + 1;
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 55b64bbcb..936e84b12 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -934,7 +934,7 @@ int SSL_waiting_for_async(SSL *s)
 int SSL_get_async_wait_fd(SSL *s)
 {
     if (!s->job)
-        return 0;
+        return -1;
 
     return ASYNC_get_wait_fd(s->job);
 }