网络爬虫，完美演示了多线程和深度设置抓取网页数据。-crawl through internet to get web data.

the win32 api supports applications that are pre-emptively multithreaded. this is a very useful and powerful feature of win32 in writing mfc internet spiders. the spider project is an example of how to use preemptive multithreading to gather information on the web using a spider/robot with the mfc wininet classes.