hide type detail when using type alias?

[myrfy001]

For the following rust code, with command cbindgen --lang C t.rs

type Context = HashMap<String, String>;

#[no_mangle]
pub extern fn new_context() -> *const Context{}

will generate the following C code:

typedef struct HashMap_String__String HashMap_String__String;

typedef struct HashMap_String__String Context;

const Context *new_context(void);

I don't want to let the enduser know the detail of Context is a HashMap_String__String, they should only know it's a type of Context, how can I do that?

Thanks

[emilio]

struct Context (HashMap<...>) should work?

[myrfy001]

It works! Thanks for the help~

[rlidwka]

struct Context (HashMap<...>) should work?

Technically, newtypes are not guaranteed to have the same memory layout as their inner types, see rust-lang/rust#87868 (comment).

I would want to put repr(transparent) on that Context so Rust compiler doesn't do anything funny. But adding it would make struct transparent to cbindgen as well.

@emilio is there a way to tell cbindgen to ignore repr(transparent) or repr(C) directives, and make the struct opaque instead? I was looking for something like /// cbindgen:opaque annotation, but nothing like this seem to exist at the moment.