diff --git a/src/epoll.c b/src/epoll.c
index d857645..2c0704e 100644
--- a/src/epoll.c
+++ b/src/epoll.c
@@ -87,7 +87,7 @@ epoll_t epoll_create() {
   /* thread-safe at the moment. */
   if (!epoll__initialized) {
     if (epoll__initialize() < 0)
-      return -1;
+      return NULL;
     epoll__initialized = 1;
   }