What are rules about using an underscore in a c identifier
http://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier
+V why_null 请备注:from博客园
http://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier
+V atob('d2h5X251bGw=')
请备注:from博客园