If you don't have a window or you don't want to process the timer messages in the window procedure, you must pass NULL to the function in place of a window handle.

如果你没有窗口或者是你不想在窗口过程中处理定时器消息，你必须在函数的窗口句柄的地方传递一空值。

youdao

If you don't have a window or you don't want to process the timer messages in the window procedure, you must pass NULL to the function in place of a window handle.

如果你没有窗口或者是你不想在窗口过程中处理定时器消息，你必须在函数的窗口句柄的地方传递一空值。

youdao