TTF_SUBCLASS If you use this flag, it means you tell the tooltip control to subclass the window that the tool is on so that the tooltip control can intercept mouse messages that are sent to the window.

• SUBCLASS如果你使用这个标志，它意味着你告诉工具提示控件子类化工具所在的窗口，以便让工具提示控件能够窃听发送给窗口的鼠标消息。