* macosx/tclMacOSXBundle.c:

	* unix/tclUnixInit.c:
	* unix/tcl.m4 (Darwin): made use of CoreFoundation API configurable
	and added test of CoreFoundation availablility to allow building on
	ppc64, replaced HAVE_CFBUNDLE by HAVE_COREFOUNDATION; test for
	availability of Tiger or later OSSpinLockLock API.

	* unix/tclUnixNotfy.c:
	* unix/Makefile.in:
	* macosx/tclMacOSXNotify.c (new file): when CoreFoundation is
	available, use new CFRunLoop based notifier: allows easy integration
	with other event loops on Mac OS X, in particular the TkAqua Carbon
	event loop is now integrated via a standard tcl event source (instead
	of TkAqua upon loading having to finalize the exsting notifier and
	replace it with its custom version). [Patch 1202052]

	* tests/unixNotfy.test: don't run unthreaded tests on Darwin
	since notifier may be using threads even in unthreaded core.

	* unix/tclUnixPort.h:
	* unix/tcl.m4 (Darwin): test for thread-unsafe realpath durning
	configure, as Darwin 7 and later realpath is threadsafe.

	* macosx/tclMacOSXBundle.c:
	* unix/tclLoadDyld.c:
	* unix/tclUnixInit.c: fixed gcc 4.0 warnings.

	* unix/configure: autoconf-2.13

1 files changed, 1030 insertions, 0 deletions

diff --git a/macosx/tclMacOSXNotify.c b/macosx/tclMacOSXNotify.c
new file mode 100644
index 0000000..bf3b9bc
--- /dev/null
+++ b/macosx/tclMacOSXNotify.c
@@ -0,0 +1,1030 @@
+/*
+ * tclMacOSXNotify.c --
+ *
+ *	This file contains the implementation of a merged 
+ *	CFRunLoop/select-based notifier, which is the lowest-level part 
+ *	of the Tcl event loop.  This file works together with
+ *	generic/tclNotify.c.
+ *
+ * Copyright (c) 1995-1997 Sun Microsystems, Inc.
+ * Copyright 2001, Apple Computer, Inc.
+ * Copyright 2005, Tcl Core Team.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * RCS: @(#) $Id: tclMacOSXNotify.c,v 1.1.2.2 2005/05/14 20:52:31 das Exp $
+ */
+
+#ifdef HAVE_COREFOUNDATION /* Traditional unix select-based notifier
+                            * is in tclUnixNotfy.c */ 
+#include "tclInt.h"
+#include "tclPort.h"
+#include <CoreFoundation/CoreFoundation.h>
+#include <pthread.h>
+
+extern TclStubs tclStubs;
+extern Tcl_NotifierProcs tclOriginalNotifier;
+
+/*
+ * This structure is used to keep track of the notifier info for a 
+ * a registered file.
+ */
+
+typedef struct FileHandler {
+    int fd;
+    int mask;			/* Mask of desired events: TCL_READABLE,
+				 * etc. */
+    int readyMask;		/* Mask of events that have been seen since the
+				 * last time file handlers were invoked for
+				 * this file. */
+    Tcl_FileProc *proc;		/* Procedure to call, in the style of
+				 * Tcl_CreateFileHandler. */
+    ClientData clientData;	/* Argument to pass to proc. */
+    struct FileHandler *nextPtr;/* Next in list of all files we care about. */
+} FileHandler;
+
+/*
+ * The following structure is what is added to the Tcl event queue when
+ * file handlers are ready to fire.
+ */
+
+typedef struct FileHandlerEvent {
+    Tcl_Event header;		/* Information that is standard for
+				 * all events. */
+    int fd;			/* File descriptor that is ready.  Used
+				 * to find the FileHandler structure for
+				 * the file (can't point directly to the
+				 * FileHandler structure because it could
+				 * go away while the event is queued). */
+} FileHandlerEvent;
+
+/*
+ *
+ * The following structure contains a set of select() masks to track
+ * readable, writable, and exceptional conditions.
+ */
+
+typedef struct SelectMasks {
+    fd_set readable;
+    fd_set writable;
+    fd_set exceptional;
+} SelectMasks;
+
+/*
+ * The following static structure contains the state information for the
+ * select based implementation of the Tcl notifier.  One of these structures
+ * is created for each thread that is using the notifier.  
+ */
+
+typedef struct ThreadSpecificData {
+    FileHandler *firstFileHandlerPtr;
+				/* Pointer to head of file handler list. */
+
+    SelectMasks checkMasks;	/* This structure is used to build up the masks
+				 * to be used in the next call to select.
+				 * Bits are set in response to calls to
+				 * Tcl_CreateFileHandler. */
+    SelectMasks readyMasks;	/* This array reflects the readable/writable
+				 * conditions that were found to exist by the
+				 * last call to select. */
+    int numFdBits;		/* Number of valid bits in checkMasks
+				 * (one more than highest fd for which
+				 * Tcl_WatchFile has been called). */
+    int onList;			/* True if it is in this list */
+    unsigned int pollState;	/* pollState is used to implement a polling 
+				 * handshake between each thread and the
+				 * notifier thread. Bits defined below. */
+    struct ThreadSpecificData *nextPtr, *prevPtr;
+				/* All threads that are currently waiting on 
+				 * an event have their ThreadSpecificData
+				 * structure on a doubly-linked listed formed
+				 * from these pointers.  You must hold the
+				 * notifierLock before accessing these
+				 * fields. */
+    CFRunLoopSourceRef runLoopSource;
+                                /* Any other thread alerts a notifier
+				 * that an event is ready to be processed
+				 * by signaling this CFRunLoopSource. */
+    CFRunLoopRef runLoop;       /* This thread's CFRunLoop, needs to be woken
+                                 * up whenever the runLoopSource is signaled. */
+    int eventReady;		/* True if an event is ready to be processed. */
+} ThreadSpecificData;
+
+static Tcl_ThreadDataKey dataKey;
+
+/*
+ * The following static indicates the number of threads that have
+ * initialized notifiers.
+ *
+ * You must hold the notifierInitLock before accessing this variable.
+ */
+
+static int notifierCount = 0;
+
+/*
+ * The following variable points to the head of a doubly-linked list of 
+ * of ThreadSpecificData structures for all threads that are currently
+ * waiting on an event.
+ *
+ * You must hold the notifierLock before accessing this list.
+ */
+
+static ThreadSpecificData *waitingListPtr = NULL;
+
+/*
+ * The notifier thread spends all its time in select() waiting for a
+ * file descriptor associated with one of the threads on the waitingListPtr
+ * list to do something interesting.  But if the contents of the
+ * waitingListPtr list ever changes, we need to wake up and restart
+ * the select() system call.  You can wake up the notifier thread by
+ * writing a single byte to the file descriptor defined below.  This
+ * file descriptor is the input-end of a pipe and the notifier thread is
+ * listening for data on the output-end of the same pipe.  Hence writing
+ * to this file descriptor will cause the select() system call to return
+ * and wake up the notifier thread.
+ *
+ * You must hold the notifierLock lock before writing to the pipe.
+ */
+
+static int triggerPipe = -1;
+static int receivePipe = -1; /* Output end of triggerPipe */
+
+/*
+ * We use Darwin-native spinlocks instead of pthread mutexes for notifier
+ * locking: this radically simplifies the implementation and lowers
+ * overhead. Note that these are not pure spinlocks, they employ various
+ * strategies to back off, making them immune to most priority-inversion
+ * livelocks (c.f. man 3 OSSpinLockLock).
+ */
+
+#if defined(HAVE_LIBKERN_OSATOMIC_H) && defined(HAVE_OSSPINLOCKLOCK)
+/* Use OSSpinLock API where available (Tiger or later) */
+#include <libkern/OSAtomic.h>
+#else
+/* Otherwise, use commpage spinlock SPI directly */
+typedef uint32_t OSSpinLock;
+extern void _spin_lock(OSSpinLock *lock);
+extern void _spin_unlock(OSSpinLock *lock);
+#define OSSpinLockLock(p) _spin_lock(p)
+#define OSSpinLockUnlock(p) _spin_unlock(p)
+#endif
+
+/*
+ * These spinlocks lock access to the global notifier state. 
+ */
+
+static OSSpinLock notifierInitLock = 0;
+static OSSpinLock notifierLock = 0;
+
+/* 
+ * Macros abstracting notifier locking/unlocking
+ */
+
+#define LOCK_NOTIFIER_INIT   OSSpinLockLock(&notifierInitLock)
+#define UNLOCK_NOTIFIER_INIT OSSpinLockUnlock(&notifierInitLock)
+#define LOCK_NOTIFIER        OSSpinLockLock(&notifierLock)
+#define UNLOCK_NOTIFIER      OSSpinLockUnlock(&notifierLock)
+
+/*
+ * The pollState bits
+ *	POLL_WANT is set by each thread before it waits on its condition
+ *		variable.  It is checked by the notifier before it does
+ *		select.
+ *	POLL_DONE is set by the notifier if it goes into select after
+ *		seeing POLL_WANT.  The idea is to ensure it tries a select
+ *		with the same bits the initial thread had set.
+ */
+#define POLL_WANT	0x1
+#define POLL_DONE	0x2
+
+/*
+ * This is the thread ID of the notifier thread that does select.
+ */
+static pthread_t notifierThread;
+
+/*
+ * Static routines defined in this file.
+ */
+
+static void	NotifierThreadProc(ClientData clientData);
+static int	FileHandlerEventProc(Tcl_Event *evPtr, int flags);
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_InitNotifier --
+ *
+ *	Initializes the platform specific notifier state.
+ *
+ * Results:
+ *	Returns a handle to the notifier state for this thread..
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+ClientData
+Tcl_InitNotifier()
+{
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    tsdPtr->eventReady = 0;
+    
+     /*
+     * Initialize CFRunLoopSource and add it to CFRunLoop of this thread
+     */
+    
+    if (!tsdPtr->runLoop) {
+        CFRunLoopRef runLoop = CFRunLoopGetCurrent();
+        CFRunLoopSourceRef runLoopSource;
+        CFRunLoopSourceContext runLoopSourceContext;
+        
+        bzero(&runLoopSourceContext, sizeof(CFRunLoopSourceContext));
+        runLoopSourceContext.info = tsdPtr;
+        runLoopSource = CFRunLoopSourceCreate(NULL, 0, &runLoopSourceContext);
+        if (!runLoopSource) {
+            Tcl_Panic("Tcl_InitNotifier: could not create CFRunLoopSource.");
+        }
+        CFRunLoopAddSource(runLoop, runLoopSource, kCFRunLoopCommonModes);
+        CFRelease(runLoopSource);
+        tsdPtr->runLoopSource = runLoopSource;
+        tsdPtr->runLoop = runLoop;
+    }
+
+    /*
+     * Initialize trigger pipe and start the Notifier thread if necessary.
+     */
+
+    LOCK_NOTIFIER_INIT;
+    if (notifierCount == 0) {
+        int fds[2], status, result;
+        pthread_attr_t attr;
+    
+        if (pipe(fds) != 0) {
+            Tcl_Panic("Tcl_InitNotifier: could not create trigger pipe.");
+        }
+        
+        status = fcntl(fds[0], F_GETFL);
+        status |= O_NONBLOCK;
+        if (fcntl(fds[0], F_SETFL, status) < 0) {
+            Tcl_Panic("Tcl_InitNotifier: could not make receive pipe non blocking.");
+        }
+        status = fcntl(fds[1], F_GETFL);
+        status |= O_NONBLOCK;
+        if (fcntl(fds[1], F_SETFL, status) < 0) {
+            Tcl_Panic("Tcl_InitNotifier: could not make trigger pipe non blocking.");
+        }
+
+        receivePipe = fds[0];
+        triggerPipe = fds[1];
+
+        pthread_attr_init(&attr);
+        pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
+        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+        pthread_attr_setstacksize(&attr, 60 * 1024);
+        result = pthread_create(&notifierThread, &attr, (void * (*)(void *))NotifierThreadProc, NULL);
+        pthread_attr_destroy(&attr);
+	if (result) {
+	    Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread.");
+	}
+    }
+    notifierCount++;
+    UNLOCK_NOTIFIER_INIT;
+    
+    return (ClientData) tsdPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_FinalizeNotifier --
+ *
+ *	This function is called to cleanup the notifier state before
+ *	a thread is terminated.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	May terminate the background notifier thread if this is the
+ *	last notifier instance.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_FinalizeNotifier(clientData)
+    ClientData clientData;		/* Not used. */
+{
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    LOCK_NOTIFIER_INIT;
+    notifierCount--;
+
+    /*
+     * If this is the last thread to use the notifier, close the notifier
+     * pipe and wait for the background thread to terminate.
+     */
+
+    if (notifierCount == 0) {
+        int result;
+        
+	if (triggerPipe < 0) {
+	    Tcl_Panic("Tcl_FinalizeNotifier: notifier pipe not initialized.");
+	}
+
+	/*
+	 * Send "q" message to the notifier thread so that it will
+	 * terminate.  The notifier will return from its call to select()
+	 * and notice that a "q" message has arrived, it will then close
+	 * its side of the pipe and terminate its thread.  Note the we can
+	 * not just close the pipe and check for EOF in the notifier
+	 * thread because if a background child process was created with
+	 * exec, select() would not register the EOF on the pipe until the
+	 * child processes had terminated. [Bug: 4139]
+	 */
+	write(triggerPipe, "q", 1);
+	close(triggerPipe);
+
+	result = pthread_join(notifierThread, NULL); 
+	if (result) {
+	    Tcl_Panic("Tcl_FinalizeNotifier: unable to join notifier thread.");
+	}
+	
+	close(receivePipe);
+        triggerPipe = -1;
+    }
+    UNLOCK_NOTIFIER_INIT;
+    
+    LOCK_NOTIFIER; /* for concurrency with Tcl_AlertNotifier */
+    if (tsdPtr->runLoop) {
+        tsdPtr->runLoop = NULL;
+        /* Remove runLoopSource from all CFRunLoops and release it */
+        CFRunLoopSourceInvalidate(tsdPtr->runLoopSource);
+        tsdPtr->runLoopSource = NULL;
+    }
+    UNLOCK_NOTIFIER;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_AlertNotifier --
+ *
+ *	Wake up the specified notifier from any thread. This routine
+ *	is called by the platform independent notifier code whenever
+ *	the Tcl_ThreadAlert routine is called.  This routine is
+ *	guaranteed not to be called on a given notifier after
+ *	Tcl_FinalizeNotifier is called for that notifier.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Signals the notifier condition variable for the specified
+ *	notifier.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_AlertNotifier(clientData)
+    ClientData clientData;
+{
+    ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData;
+    LOCK_NOTIFIER;
+    if (tsdPtr->runLoop) {
+        tsdPtr->eventReady = 1;
+        CFRunLoopSourceSignal(tsdPtr->runLoopSource);
+        CFRunLoopWakeUp(tsdPtr->runLoop);
+    }
+    UNLOCK_NOTIFIER;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_SetTimer --
+ *
+ *	This procedure sets the current notifier timer value.  This
+ *	interface is not implemented in this notifier because we are
+ *	always running inside of Tcl_DoOneEvent.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_SetTimer(timePtr)
+    Tcl_Time *timePtr;		/* Timeout value, may be NULL. */
+{
+    /*
+     * The interval timer doesn't do anything in this implementation,
+     * because the only event loop is via Tcl_DoOneEvent, which passes
+     * timeout values to Tcl_WaitForEvent.
+     */
+
+    if (tclStubs.tcl_SetTimer != tclOriginalNotifier.setTimerProc) {
+	tclStubs.tcl_SetTimer(timePtr);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_ServiceModeHook --
+ *
+ *	This function is invoked whenever the service mode changes.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_ServiceModeHook(mode)
+    int mode;			/* Either TCL_SERVICE_ALL, or
+				 * TCL_SERVICE_NONE. */
+{
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CreateFileHandler --
+ *
+ *	This procedure registers a file handler with the select notifier.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Creates a new file handler structure.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_CreateFileHandler(fd, mask, proc, clientData)
+    int fd;			/* Handle of stream to watch. */
+    int mask;			/* OR'ed combination of TCL_READABLE,
+				 * TCL_WRITABLE, and TCL_EXCEPTION:
+				 * indicates conditions under which
+				 * proc should be called. */
+    Tcl_FileProc *proc;		/* Procedure to call for each
+				 * selected event. */
+    ClientData clientData;	/* Arbitrary data to pass to proc. */
+{
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+    FileHandler *filePtr;
+
+    if (tclStubs.tcl_CreateFileHandler != tclOriginalNotifier.createFileHandlerProc) {
+	tclStubs.tcl_CreateFileHandler(fd, mask, proc, clientData);
+	return;
+    }
+
+    for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL;
+	    filePtr = filePtr->nextPtr) {
+	if (filePtr->fd == fd) {
+	    break;
+	}
+    }
+    if (filePtr == NULL) {
+	filePtr = (FileHandler*) ckalloc(sizeof(FileHandler));
+	filePtr->fd = fd;
+	filePtr->readyMask = 0;
+	filePtr->nextPtr = tsdPtr->firstFileHandlerPtr;
+	tsdPtr->firstFileHandlerPtr = filePtr;
+    }
+    filePtr->proc = proc;
+    filePtr->clientData = clientData;
+    filePtr->mask = mask;
+
+    /*
+     * Update the check masks for this file.
+     */
+
+    if (mask & TCL_READABLE) {
+	FD_SET(fd, &(tsdPtr->checkMasks.readable));
+    } else {
+	FD_CLR(fd, &(tsdPtr->checkMasks.readable));
+    }
+    if (mask & TCL_WRITABLE) {
+	FD_SET(fd, &(tsdPtr->checkMasks.writable));
+    } else {
+	FD_CLR(fd, &(tsdPtr->checkMasks.writable));
+    }
+    if (mask & TCL_EXCEPTION) {
+	FD_SET(fd, &(tsdPtr->checkMasks.exceptional));
+    } else {
+	FD_CLR(fd, &(tsdPtr->checkMasks.exceptional));
+    }
+    if (tsdPtr->numFdBits <= fd) {
+	tsdPtr->numFdBits = fd+1;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_DeleteFileHandler --
+ *
+ *	Cancel a previously-arranged callback arrangement for
+ *	a file.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	If a callback was previously registered on file, remove it.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_DeleteFileHandler(fd)
+    int fd;		/* Stream id for which to remove callback procedure. */
+{
+    FileHandler *filePtr, *prevPtr;
+    int i;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (tclStubs.tcl_DeleteFileHandler != tclOriginalNotifier.deleteFileHandlerProc) {
+	tclStubs.tcl_DeleteFileHandler(fd);
+	return;
+    }
+
+    /*
+     * Find the entry for the given file (and return if there isn't one).
+     */
+
+    for (prevPtr = NULL, filePtr = tsdPtr->firstFileHandlerPtr; ;
+	 prevPtr = filePtr, filePtr = filePtr->nextPtr) {
+	if (filePtr == NULL) {
+	    return;
+	}
+	if (filePtr->fd == fd) {
+	    break;
+	}
+    }
+
+    /*
+     * Update the check masks for this file.
+     */
+
+    if (filePtr->mask & TCL_READABLE) {
+	FD_CLR(fd, &(tsdPtr->checkMasks.readable));
+    }
+    if (filePtr->mask & TCL_WRITABLE) {
+	FD_CLR(fd, &(tsdPtr->checkMasks.writable));
+    }
+    if (filePtr->mask & TCL_EXCEPTION) {
+	FD_CLR(fd, &(tsdPtr->checkMasks.exceptional));
+    }
+
+    /*
+     * Find current max fd.
+     */
+
+    if (fd+1 == tsdPtr->numFdBits) {
+	tsdPtr->numFdBits = 0;
+	for (i = fd-1; i >= 0; i--) {
+	    if (FD_ISSET(i, &(tsdPtr->checkMasks.readable))
+		    || FD_ISSET(i, &(tsdPtr->checkMasks.writable))
+		    || FD_ISSET(i, &(tsdPtr->checkMasks.exceptional))) {
+		tsdPtr->numFdBits = i+1;
+		break;
+	    }
+	}
+    }
+
+    /*
+     * Clean up information in the callback record.
+     */
+
+    if (prevPtr == NULL) {
+	tsdPtr->firstFileHandlerPtr = filePtr->nextPtr;
+    } else {
+	prevPtr->nextPtr = filePtr->nextPtr;
+    }
+    ckfree((char *) filePtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FileHandlerEventProc --
+ *
+ *	This procedure is called by Tcl_ServiceEvent when a file event
+ *	reaches the front of the event queue.  This procedure is
+ *	responsible for actually handling the event by invoking the
+ *	callback for the file handler.
+ *
+ * Results:
+ *	Returns 1 if the event was handled, meaning it should be removed
+ *	from the queue.  Returns 0 if the event was not handled, meaning
+ *	it should stay on the queue.  The only time the event isn't
+ *	handled is if the TCL_FILE_EVENTS flag bit isn't set.
+ *
+ * Side effects:
+ *	Whatever the file handler's callback procedure does.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+FileHandlerEventProc(evPtr, flags)
+    Tcl_Event *evPtr;		/* Event to service. */
+    int flags;			/* Flags that indicate what events to
+				 * handle, such as TCL_FILE_EVENTS. */
+{
+    int mask;
+    FileHandler *filePtr;
+    FileHandlerEvent *fileEvPtr = (FileHandlerEvent *) evPtr;
+    ThreadSpecificData *tsdPtr;
+
+    if (!(flags & TCL_FILE_EVENTS)) {
+	return 0;
+    }
+
+    /*
+     * Search through the file handlers to find the one whose handle matches
+     * the event.  We do this rather than keeping a pointer to the file
+     * handler directly in the event, so that the handler can be deleted
+     * while the event is queued without leaving a dangling pointer.
+     */
+
+    tsdPtr = TCL_TSD_INIT(&dataKey);
+    for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL;
+	    filePtr = filePtr->nextPtr) {
+	if (filePtr->fd != fileEvPtr->fd) {
+	    continue;
+	}
+
+	/*
+	 * The code is tricky for two reasons:
+	 * 1. The file handler's desired events could have changed
+	 *    since the time when the event was queued, so AND the
+	 *    ready mask with the desired mask.
+	 * 2. The file could have been closed and re-opened since
+	 *    the time when the event was queued.  This is why the
+	 *    ready mask is stored in the file handler rather than
+	 *    the queued event:  it will be zeroed when a new
+	 *    file handler is created for the newly opened file.
+	 */
+
+	mask = filePtr->readyMask & filePtr->mask;
+	filePtr->readyMask = 0;
+	if (mask != 0) {
+	    (*filePtr->proc)(filePtr->clientData, mask);
+	}
+	break;
+    }
+    return 1;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_WaitForEvent --
+ *
+ *	This function is called by Tcl_DoOneEvent to wait for new
+ *	events on the message queue.  If the block time is 0, then
+ *	Tcl_WaitForEvent just polls without blocking.
+ *
+ * Results:
+ *	Returns -1 if the select would block forever, otherwise
+ *	returns 0.
+ *
+ * Side effects:
+ *	Queues file events that are detected by the select.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_WaitForEvent(timePtr)
+    Tcl_Time *timePtr;		/* Maximum block time, or NULL. */
+{
+    FileHandler *filePtr;
+    FileHandlerEvent *fileEvPtr;
+    int mask;
+    int waitForFiles;
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    if (tclStubs.tcl_WaitForEvent != tclOriginalNotifier.waitForEventProc) {
+	return tclStubs.tcl_WaitForEvent(timePtr);
+    }
+
+    /*
+     * Place this thread on the list of interested threads, signal the
+     * notifier thread, and wait for a response or a timeout.
+     */
+
+    LOCK_NOTIFIER;
+
+    waitForFiles = (tsdPtr->numFdBits > 0);
+    if (timePtr != NULL && timePtr->sec == 0 && timePtr->usec == 0) {
+	/*
+	 * Cannot emulate a polling select with a polling condition variable.
+	 * Instead, pretend to wait for files and tell the notifier
+	 * thread what we are doing.  The notifier thread makes sure
+	 * it goes through select with its select mask in the same state
+	 * as ours currently is.  We block until that happens.
+	 */
+
+	waitForFiles = 1;
+	tsdPtr->pollState = POLL_WANT;
+	timePtr = NULL;
+    } else {
+	tsdPtr->pollState = 0;
+    }
+
+    if (waitForFiles) {
+	/*
+	 * Add the ThreadSpecificData structure of this thread to the list
+	 * of ThreadSpecificData structures of all threads that are waiting
+	 * on file events.
+	 */
+
+	tsdPtr->nextPtr = waitingListPtr;
+	if (waitingListPtr) {
+	    waitingListPtr->prevPtr = tsdPtr;
+	}
+	tsdPtr->prevPtr = 0;
+	waitingListPtr = tsdPtr;
+	tsdPtr->onList = 1;
+
+	write(triggerPipe, "", 1);
+    }
+
+    FD_ZERO(&(tsdPtr->readyMasks.readable));
+    FD_ZERO(&(tsdPtr->readyMasks.writable));
+    FD_ZERO(&(tsdPtr->readyMasks.exceptional));
+
+    if (!tsdPtr->eventReady) {
+        CFTimeInterval waitTime;
+
+        if (timePtr == NULL) {
+            waitTime = 1.0e10; /* Wait forever, as per CFRunLoop.c */
+        } else {
+            waitTime = timePtr->sec + 1.0e-6 * timePtr->usec;
+        }
+        UNLOCK_NOTIFIER;
+        CFRunLoopRunInMode(kCFRunLoopDefaultMode, waitTime, TRUE);
+        LOCK_NOTIFIER;
+    }
+    tsdPtr->eventReady = 0;
+
+    if (waitForFiles && tsdPtr->onList) {
+	/*
+	 * Remove the ThreadSpecificData structure of this thread from the
+	 * waiting list.  Alert the notifier thread to recompute its select
+	 * masks - skipping this caused a hang when trying to close a pipe
+	 * which the notifier thread was still doing a select on.
+	 */
+
+	if (tsdPtr->prevPtr) {
+	    tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr;
+	} else {
+	    waitingListPtr = tsdPtr->nextPtr;
+	}
+	if (tsdPtr->nextPtr) {
+	    tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr;
+	}
+	tsdPtr->nextPtr = tsdPtr->prevPtr = NULL;
+	tsdPtr->onList = 0;
+	write(triggerPipe, "", 1);
+    }
+
+    
+    /*
+     * Queue all detected file events before returning.
+     */
+
+    for (filePtr = tsdPtr->firstFileHandlerPtr; (filePtr != NULL);
+	    filePtr = filePtr->nextPtr) {
+
+	mask = 0;
+	if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.readable))) {
+	    mask |= TCL_READABLE;
+	}
+	if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.writable))) {
+	    mask |= TCL_WRITABLE;
+	}
+	if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.exceptional))) {
+	    mask |= TCL_EXCEPTION;
+	}
+
+	if (!mask) {
+	    continue;
+	}
+
+	/*
+	 * Don't bother to queue an event if the mask was previously
+	 * non-zero since an event must still be on the queue.
+	 */
+
+	if (filePtr->readyMask == 0) {
+	    fileEvPtr = (FileHandlerEvent *) ckalloc(sizeof(FileHandlerEvent));
+	    fileEvPtr->header.proc = FileHandlerEventProc;
+	    fileEvPtr->fd = filePtr->fd;
+	    Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL);
+	}
+	filePtr->readyMask = mask;
+    }
+    UNLOCK_NOTIFIER;
+    return 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * NotifierThreadProc --
+ *
+ *	This routine is the initial (and only) function executed by the
+ *	special notifier thread.  Its job is to wait for file descriptors
+ *	to become readable or writable or to have an exception condition
+ *	and then to notify other threads who are interested in this
+ *	information by signalling a condition variable.  Other threads
+ *	can signal this notifier thread of a change in their interests
+ *	by writing a single byte to a special pipe that the notifier
+ *	thread is monitoring.
+ *
+ * Result:
+ *	None.  Once started, this routine never exits.  It dies with
+ *	the overall process.
+ *
+ * Side effects:
+ *	The trigger pipe used to signal the notifier thread is created
+ *	when the notifier thread first starts.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+NotifierThreadProc(clientData)
+    ClientData clientData;	/* Not used. */
+{
+    ThreadSpecificData *tsdPtr;
+    fd_set readableMask;
+    fd_set writableMask;
+    fd_set exceptionalMask;
+    int i, numFdBits = 0;
+    long found;
+    struct timeval poll = {0., 0.}, *timePtr;
+    char buf[2];
+
+    /*
+     * Look for file events and report them to interested threads.
+     */
+
+    while (1) {
+	FD_ZERO(&readableMask);
+	FD_ZERO(&writableMask);
+	FD_ZERO(&exceptionalMask);
+
+	/*
+	 * Compute the logical OR of the select masks from all the
+	 * waiting notifiers.
+	 */
+
+	LOCK_NOTIFIER;
+	timePtr = NULL;
+	for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) {
+	    for (i = tsdPtr->numFdBits-1; i >= 0; --i) {
+		if (FD_ISSET(i, &(tsdPtr->checkMasks.readable))) {
+		    FD_SET(i, &readableMask);
+		}
+		if (FD_ISSET(i, &(tsdPtr->checkMasks.writable))) {
+		    FD_SET(i, &writableMask);
+		}
+		if (FD_ISSET(i, &(tsdPtr->checkMasks.exceptional))) {
+		    FD_SET(i, &exceptionalMask);
+		}
+	    }
+	    if (tsdPtr->numFdBits > numFdBits) {
+		numFdBits = tsdPtr->numFdBits;
+	    }
+	    if (tsdPtr->pollState & POLL_WANT) {
+		/*
+		 * Here we make sure we go through select() with the same
+		 * mask bits that were present when the thread tried to poll.
+		 */
+
+		tsdPtr->pollState |= POLL_DONE;
+		timePtr = &poll;
+	    }
+	}
+	UNLOCK_NOTIFIER;
+
+	/*
+	 * Set up the select mask to include the receive pipe.
+	 */
+
+	if (receivePipe >= numFdBits) {
+	    numFdBits = receivePipe + 1;
+	}
+	FD_SET(receivePipe, &readableMask);
+
+	if (select(numFdBits, &readableMask, &writableMask, &exceptionalMask,
+		timePtr) == -1) {
+	    /*
+	     * Try again immediately on an error.
+	     */
+
+	    continue;
+	}
+
+	/*
+	 * Alert any threads that are waiting on a ready file descriptor.
+	 */
+
+	LOCK_NOTIFIER;
+	for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) {
+	    found = 0;
+
+	    for (i = tsdPtr->numFdBits-1; i >= 0; --i) {
+		if (FD_ISSET(i, &(tsdPtr->checkMasks.readable))
+			&& FD_ISSET(i, &readableMask)) {
+		    FD_SET(i, &(tsdPtr->readyMasks.readable));
+		    found = 1;
+		}
+		if (FD_ISSET(i, &(tsdPtr->checkMasks.writable))
+			&& FD_ISSET(i, &writableMask)) {
+		    FD_SET(i, &(tsdPtr->readyMasks.writable));
+		    found = 1;
+		}
+		if (FD_ISSET(i, &(tsdPtr->checkMasks.exceptional))
+			&& FD_ISSET(i, &exceptionalMask)) {
+		    FD_SET(i, &(tsdPtr->readyMasks.exceptional));
+		    found = 1;
+		}
+	    }
+
+	    if (found || (tsdPtr->pollState & POLL_DONE)) {
+		tsdPtr->eventReady = 1;
+		if (tsdPtr->onList) {
+		    /*
+		     * Remove the ThreadSpecificData structure of this
+		     * thread from the waiting list. This prevents us from
+		     * continuously spining on select until the other
+		     * threads runs and services the file event.
+		     */
+
+		    if (tsdPtr->prevPtr) {
+			tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr;
+		    } else {
+			waitingListPtr = tsdPtr->nextPtr;
+		    }
+		    if (tsdPtr->nextPtr) {
+			tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr;
+		    }
+		    tsdPtr->nextPtr = tsdPtr->prevPtr = NULL;
+		    tsdPtr->onList = 0;
+		    tsdPtr->pollState = 0;
+		}
+		if (tsdPtr->runLoop) {
+		    CFRunLoopSourceSignal(tsdPtr->runLoopSource);
+		    CFRunLoopWakeUp(tsdPtr->runLoop);
+		}
+	    }
+	}
+	UNLOCK_NOTIFIER;
+
+	/*
+	 * Consume the next byte from the notifier pipe if the pipe was
+	 * readable.  Note that there may be multiple bytes pending, but
+	 * to avoid a race condition we only read one at a time.
+	 */
+
+	if (FD_ISSET(receivePipe, &readableMask)) {
+	    i = read(receivePipe, buf, 1);
+
+	    if ((i == 0) || ((i == 1) && (buf[0] == 'q'))) {
+		/*
+		 * Someone closed the write end of the pipe or sent us a
+		 * Quit message [Bug: 4139] and then closed the write end
+		 * of the pipe so we need to shut down the notifier thread.
+		 */
+
+		break;
+	    }
+	}
+    }
+    pthread_exit (0);
+}
+
+#endif /* HAVE_COREFOUNDATION */