diff --git a/unix/configure.in b/unix/configure.in

index b606b74..46dec02 100755

--- a/unix/configure.in

+++ b/unix/configure.in

@@ -491,6 +491,12 @@ SC_ENABLE_LANGINFO

 AC_CHECK_FUNCS(chflags)

 #--------------------------------------------------------------------

+# Check for support of pthread_atfork function

+#--------------------------------------------------------------------

+

+AC_CHECK_FUNCS(pthread_atfork)

+

+#--------------------------------------------------------------------

 # Check for support of isnan() function or macro

 #--------------------------------------------------------------------

@@ -513,7 +519,6 @@ if test "`uname -s`" = "Darwin" ; then

     if test $tcl_corefoundation = yes; then

 	AC_CHECK_HEADERS(libkern/OSAtomic.h)

 	AC_CHECK_FUNCS(OSSpinLockLock)

-	AC_CHECK_FUNCS(pthread_atfork)

     fi

     AC_DEFINE(USE_VFORK, 1, [Should we use vfork() instead of fork()?])

     AC_DEFINE(TCL_DEFAULT_ENCODING, "utf-8",

diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c

index 51f0b1f..9006906 100644

--- a/unix/tclUnixNotfy.c

+++ b/unix/tclUnixNotfy.c

@@ -128,6 +128,15 @@ static Tcl_ThreadDataKey dataKey;

 static int notifierCount = 0;

 /*

+ * The following static stores the process ID of the initialized notifier

+ * thread. If it changes, we have passed a fork and we should start a new

+ * notifier thread.

+ *

+ * You must hold the notifierMutex lock before accessing this variable.

+ */

+static pid_t processIDInitialized = 0;

+

+/*

  * The following variable points to the head of a doubly-linked list of

  * ThreadSpecificData structures for all threads that are currently waiting on

  * an event.

@@ -193,7 +202,13 @@ static Tcl_ThreadId notifierThread;

 #ifdef TCL_THREADS

 static void	NotifierThreadProc(ClientData clientData);

-#endif

+#ifdef HAVE_PTHREAD_ATFORK

+static int	atForkInit = 0;

+static void	AtForkPrepare(void);

+static void	AtForkParent(void);

+static void	AtForkChild(void);

+#endif /* HAVE_PTHREAD_ATFORK */

+#endif /* TCL_THREADS */

 static int	FileHandlerEventProc(Tcl_Event *evPtr, int flags);

 /*

@@ -267,11 +282,38 @@ Tcl_InitNotifier(void)

      */

     Tcl_MutexLock(&notifierMutex);

+#ifdef HAVE_PTHREAD_ATFORK

+    /*

+     * Install pthread_atfork handlers to reinitialize the notifier in the

+     * child of a fork.

+     */

+

+    if (!atForkInit) {

+	int result = pthread_atfork(AtForkPrepare, AtForkParent, AtForkChild);

+

+	if (result) {

+	    Tcl_Panic("Tcl_InitNotifier: pthread_atfork failed");

+	}

+	atForkInit = 1;

+    }

+#endif

+    /*

+     * Check if my process id changed, e.g. I was forked

+     * In this case, restart the notifier thread and close the

+     * pipe to the original notifier thread

+     */

+    if (notifierCount > 0 && processIDInitialized != getpid()) {

+        notifierCount = 0;

+        processIDInitialized = 0;

+        close(triggerPipe);

+        triggerPipe = -1;

+    }

     if (notifierCount == 0) {

 	if (TclpThreadCreate(&notifierThread, NotifierThreadProc, NULL,

 		TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) {

 	    Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread");

 	}

+	processIDInitialized = getpid();

     }

     notifierCount++;

@@ -1230,6 +1272,73 @@ NotifierThreadProc(

     TclpThreadExit (0);

 }

+

+#ifdef HAVE_PTHREAD_ATFORK

+/*

+ *----------------------------------------------------------------------

+ *

+ * AtForkPrepare --

+ *

+ *	Lock the notifier in preparation for a fork.

+ *

+ * Results:

+ *	None.

+ *

+ * Side effects:

+ *	None.

+ *

+ *----------------------------------------------------------------------

+ */

+

+static void

+AtForkPrepare(void)

+{

+}

+

+/*

+ *----------------------------------------------------------------------

+ *

+ * AtForkParent --

+ *

+ *	Unlock the notifier in the parent after a fork.

+ *

+ * Results:

+ *	None.

+ *

+ * Side effects:

+ *	None.

+ *

+ *----------------------------------------------------------------------

+ */

+

+static void

+AtForkParent(void)

+{

+}

+

+/*

+ *----------------------------------------------------------------------

+ *

+ * AtForkChild --

+ *

+ *	Unlock and reinstall the notifier in the child after a fork.

+ *

+ * Results:

+ *	None.

+ *

+ * Side effects:

+ *	None.

+ *

+ *----------------------------------------------------------------------

+ */

+

+static void

+AtForkChild(void)

+{

+    Tcl_InitNotifier();

+}

+#endif /* HAVE_PTHREAD_ATFORK */

+

 #endif /* TCL_THREADS */

 #endif /* HAVE_COREFOUNDATION */