You are strict in your definition of `sizeOf`. You probably want: sizeOf ~SignedMessage{messageLength} = ... On Mon, 28 Nov 2022, at 4:04 PM, Hécate wrote:
Hi everyone,
In a fit of madness I have found myself writing Haskell code where I need to implement a Storable instance. However, by virtue of not being a C programmer, I'm fairly lost on some of the details, especially the value of the sizeOf and alignment methods.
My Haskell-level record is the following:
data SignedMessage = SignedMessage { messageLength :: CSize , messageForeignPtr :: ForeignPtr CUChar , signatureForeignPtr :: ForeignPtr CUChar }
Here is the code of the Storable instance: https://gist.github.com/Kleidukos/31346d067f309f2a86cbd97a85c0f1e8#file-sign...
And so I used `hedgehog-classes` to test the Storable instance. However, all the tests fail with the same reason: Prelude.undefined:
https://gist.github.com/Kleidukos/31346d067f309f2a86cbd97a85c0f1e8#file-unde...
The main problem (and that's certainly a red herring for me) is that the `undefined` call comes frombase:Foreign.Marshal.Array. Which shouldn't be a problem, as it is not supposed to be evaluated! Yet apparently it is.
If you're interested to see the full code, it's located here: https://github.com/haskell-cryptography/libsodium-bindings/blob/add-sel-pack...
I'm not sure how to proceed from here. What would be a good angle to approach this?
Cheers, Hécate
-- Hécate ✨ 🐦: @TechnoEmpress IRC: Hecate WWW: https://glitchbra.in RUN: BSD
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