Cbindgen Unsupported type: Type::Slice for Vec <u32> problem

help
1

I attempt to generate C header for the Rust code here using the command

cbindgen --config cbindgen.toml --crate tiktoken --lang c --output tiktoken.h

where the cbindgen.toml is just an empty file.

But the command throws several errors, one of them is

ERROR: Cannot use fn tiktoken::byte_pair_encode (Unsupported type: Type::Slice { bracket_token: Bracket, elem: Type::Path { qself: None, path: Path { leading_colon: None, segments: [PathSegment { ident: Ident(u8), arguments: PathArguments::None }] } } }).

It seems to me it's because no Vec type at the C side. So I create a custom Vector struct and modify some corresponded code. Though Rust compilation works, but the error still remains. What might go wrong? And how to fix it? Thanks.

#[repr(C)]
pub struct Vector {
    ptr: *mut u32,
    len: usize,
    capacity: usize,
}
impl Vector {
    pub fn to_vec(&self) -> Vec<u32> {
        unsafe { Vec::<u32>::from_raw_parts(self.ptr, self.len, self.capacity) }
    }
}
2

The error is telling you that the type &[u8] is unsupported, you'll have to use a FFI-safe version of that as well.

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