Event Tap(CFMachPortRef) problem for Hot Key- callback is not invoked

I am developing a desktop application that supports one of the feature through Hot Key. I am using Event Tap for this to work.

But, sometimes (randomly) the callback is not invoked; Hot Key does not work and hence the feature seems to be not working.

Could someone help me out in identifying the problem here.

Following is the code snippet:

-( void )startEventTapinThread //Called in a separate thread.
{
    NSAutoreleasePool *pool =[ [ NSAutoreleasePool alloc] init];

    CFRunLoopRef runloop =(CFRunLoopRef)CFRunLoopGetCurrent();
    CGEventMask interestedEvents = CGEventMaskBit(kCGEventFlagsChanged)|CGEventMaskBit(kCGEventKeyDown);
    CFMachPortRef eventTap = CGEventTapCreate(kCGSessionEventTap, kCGHeadInsertEventTap, 0, i开发者_开发技巧nterestedEvents, myCGEventCallback, self); //self is the object pointer our method
    CFRunLoopSourceRef source = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, eventTap, 0);
    CFRunLoopAddSource((CFRunLoopRef)runloop , source, kCFRunLoopCommonModes);
    CFRunLoopRun();
    [ pool release];
}

CGEventRef myCGEventCallback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon)
{
    CGEventType eventType = CGEventGetType(event);
    //execute the code related to feature
}

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I would pass the event kCGEventMaskForAllEvents rather than only set the hook for certain events.

Then, in your callback function, filter the events.

CGEventRef myCGEventCallback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon)
{

if (type == kCGEventTapDisabledByTimeout) {
    NSLog(@"Event Taps Disabled! Re-enabling");
    CGEventTapEnable(eventTap, true);
    return event;
}

if (type == kCGEventLeftMouseDown) {
    //...
}

if (type != kCGEventKeyDown) {
    //...
}

if (type == kCGEventKeyDown) {
    //...
}

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The solution to your problem is most likely described in the top answer to this question. I would mark this question as a dupe if I had the rep score to do so.