--- libev/ev_kqueue.c	2011/06/04 05:33:29	1.51
+++ libev/ev_kqueue.c	2014/01/16 11:51:05	1.55
@@ -1,7 +1,7 @@
 /*
  * libev kqueue backend
  *
- * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libev@schmorp.de>
+ * Copyright (c) 2007,2008,2009,2010,2011,2012,2013 Marc Alexander Lehmann <libev@schmorp.de>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modifica-
@@ -155,7 +155,8 @@
 int inline_size
 kqueue_init (EV_P_ int flags)
 {
-  /* Initialize the kernel queue */
+  /* initialize the kernel queue */
+  kqueue_fd_pid = getpid ();
   if ((backend_fd = kqueue ()) < 0)
     return 0;
 
@@ -185,8 +186,20 @@
 void inline_size
 kqueue_fork (EV_P)
 {
-  close (backend_fd);
+  /* some BSD kernels don't just destroy the kqueue itself,
+   * but also close the fd, which isn't documented, and
+   * impossible to support properly.
+   * we remember the pid of the kqueue call and only close
+   * the fd if the pid is still the same.
+   * this leaks fds on sane kernels, but BSD interfaces are
+   * notoriously buggy and rarely get fixed.
+   */
+  pid_t newpid = getpid ();
 
+  if (newpid == kqueue_fd_pid)
+    close (backend_fd);
+
+  kqueue_fd_pid = newpid;
   while ((backend_fd = kqueue ()) < 0)
     ev_syserr ("(libev) kqueue");
 
@@ -196,3 +209,6 @@
   fd_rearm_all (EV_A);
 }
 
+/* sys/event.h defines EV_ERROR */
+#undef EV_ERROR
+