gistfile1.m

- (void) setupSockets {
    void* info = (__bridge void*) self;
    readsock = CFSocketCreate(kCFAllocatorDefault, PF_INET, SOCK_DGRAM,
                              IPPROTO_UDP, kCFSocketReadCallBack |
                              kCFSocketAcceptCallBack | kCFSocketDataCallBack |
                              kCFSocketConnectCallBack | kCFSocketWriteCallBack,
                              (CFSocketCallBack)readSockCallBack, info);
    ....
}

void readSockCallBack(CFSocketRef sock, CFSocketCallBackType type, CFDataRef addr,
                      const void* d, void* info) {
    switch (type) {
        case kCFSocketDataCallBack: {
               CFDataRef data = (CFDataRef) d;
            NetDrawPoint p;
            memcpy(&p, CFDataGetBytePtr(data), sizeof(p));
            CanvasView* self = (__bridge CanvasView*) info;
            [self addPoint:p]; // <----- This causes the crash
        }
    }
}

// Here's the error:
2011-09-06 10:18:19.007 NetDraw[53224:f203] -[CALayer addPoint:]: unrecognized selector sent to instance 0x7678890
2011-09-06 10:18:19.061 NetDraw[53224:f203] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CALayer addPoint:]: unrecognized selector sent to instance 0x7678890'
*** First throw call stack: