cgo C.uint64_t compatiblity on multiple platforms?

[David Stainton]

Greetings,

I think my question is something like: "how to make my usage of C.uint64_t work on all platforms?" or "Is there something obviously wrong with my cgo bindings that is causing this not to build on all platforms?"

I wrote this cgo binding for the reference implementation of Sphincs+ (it's a hash based post quantum signature scheme):

https://github.com/katzenpost/katzenpost/blob/main/sphincsplus/ref/binding.go

Recently we noticed it fails to build on MacOS and Windows:

https://github.com/katzenpost/katzen/actions/runs/3609590801/jobs/6082872618

So I "fixed" it by changing the typecast to use C.uint64_t instead of C.ulong:

https://github.com/katzenpost/katzenpost/pull/110/files

However that causes the build to fail using Go1.19.3 on MacOS, although it works on Windows:

https://github.com/katzenpost/katzen/actions/runs/3609771045/jobs/6083165054

Sincerely,

David Stainton

[Dan Kortschak]

The header file definition for crypto_sign_signature uses size_t for
the parameters that are passed as ulong in the calls that are causing
the issue. These types are not always the same size, so perhaps in e.g.
https://github.com/katzenpost/katzenpost/blob/a165cb2a13e40f3a15dd1fa296a7763d8b638ae0/sphincsplus/ref/binding.go#L120-L125
making the ulong params be size_t would help.

[David Stainton]

Thanks, yes switching those type casts to C.size_t worked.