32、应用开发中的地址簿功能实现

应用开发中的地址簿功能实现

1. 发送响应

在处理传入数据后，发送响应相对简单。借助 dispatch_io ，只需调用一次 dispatch_io_write() 即可完成响应发送， dispatch API 会处理等待和缓冲区管理。以下是发送数据的代码示例：

- (void) sendData: (NSData *) data
{
    // the queue for all blocks here
    dispatch_queue_t q = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    // we want a dispatch_data_t referencing this NSData object
    // the logical thing is to have the dispatch cleanup block reference & release
    //  the NSData, except we can't call -release on it under ARC. The solution is to
    //  bridge-cast the NSData to a manually-counted CFDataRef, which we can release.
    CFDataRef cfData = CFBridgingRetain(data);
    dispatch_data_t dda