1 files changed, 14 insertions, 35 deletions
diff --git a/macosx/tkMacOSXEvent.c b/macosx/tkMacOSXEvent.c
index af68eb6..66ca964 100644
--- a/macosx/tkMacOSXEvent.c
+++ b/macosx/tkMacOSXEvent.c
@@ -104,47 +104,26 @@ enum {
     return processedEvent;
 }
 @end
-
 #pragma mark -
-
-/*
- *----------------------------------------------------------------------
- *
- * XSync --
- *
- *	This routine is a stub called XSync, which is called during the Tk
- *      update command.  The language specification does not require that the
- *      update command be synchronous but many of the tests implicitly assume
- *      that it is.  It is definitely asynchronous on macOS since many idle
- *      tasks are run inside of the drawRect method of a window's contentView,
- *      which will not be called until after this function returns.
- *
- * Results:
- *	None.
- *
- * Side effects: Processes all pending idle events then calls the display
- *	method of each visible window.
- *
- *----------------------------------------------------------------------
- */
-
 int
 XSync(
     Display *display,
-    Bool discard)
+    TCL_UNUSED(Bool))
 {
-    (void)discard;
+    /*
+     *  The main use of XSync is by the update command, which alternates
+     *  between running an event loop to process all events without waiting and
+     *  calling XSync on all displays until no events are left.  There is
+     *  nothing for the mac to do with respect to syncing its one display but
+     *  it can (and, during regression testing, frequently does) happen that
+     *  timer events fire during the event loop. Processing those here seems
+     *  to make the update command work in a way that is more consistent with
+     *  its behavior on other platforms.
+     */
 
-    if (display) {
-	display->request++;
-    }
-    if (Tk_GetNumMainWindows() != 0) {
-	while (Tcl_DoOneEvent(TCL_IDLE_EVENTS)){}
-	for (NSWindow *w in [NSApp orderedWindows]) {
-	    [w display];
-	}
-    }
-    return Success;
+    while (Tcl_DoOneEvent(TCL_TIMER_EVENTS|TCL_DONT_WAIT)){}
+    display->request++;
+    return 0;
 }
 
 /*