In win32 programming, how do I CreateWindowEx that doesn't appear in taskbar and in alt+tab list?

In win32 programming, how do I CreateWindowEx that doesn't appear in
taskbar and in alt+tab list?

What window styles do I pass to CreateWindowEx so that the window doesn't
appear in taskbar and in alt+tab list?
I'm passing WS_EX_TOOLWINDOW, which achieves but the window I'm creating
is not really a "tool window".