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(¬ifierMutex);
+#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(¬ifierThread, 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 */