The type on "Ptr" doesn't actually affect what's inside; it's a convenience for programmers. The functions that do things with XEvents just read bytes from the Ptr's location.

On Tue, Nov 6, 2018, 10:36 Guru Devanla <gurudev.devanla@gmail.com wrote:
Hello Haskell-Cafe,

I have been recently studying the XMonad code and some related types available in the X11 bindings library.

I came across this type:

newtype XEvent = XEvent XEventPtr

type XEventPtr = Ptr XEvent

Available here: 
http://hackage.haskell.org/package/X11-1.9/docs/Graphics-X11-Xlib-Event.html#t:XEvent

It seems that this type is circular here. how does one use this type? Is it possible to create a value out of this type? What is the use of this type?

Please could someone help me wrap my head around this?

Thanks






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