CODEWITHSUNDEEP
rustffi
Denis Kreshikhin
Denis Kreshikhin

Reputation: 9410

How to define extern type?

I have some c functions with a struct pointer argument.

extern "C" {
    fn InitSomeStruct() -> *SomeStruct;
    fn SomeFunction(v: *SomeStruct);
    fn DestroySomeStruct(v: *SomeStruct);
}

fn main() {
    unsafe {
        let s = InitSomeStruct();
        SomeFunction(s);
        DestroySomeStruct(s);
    }
}

The implementation of SomeStruct is unknown. How to declare and use external struct like SomeStruct from the rust code?

Upvotes: 0

Views: 735

Answers (1)

huon
huon

Reputation: 102066

The convention is to use an empty enum for opaque FFI types, that is:

enum SomeStruct {}

An empty struct like struct SomeStruct; is also used sometimes.

Upvotes: 2

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