Re: [PATCH 04/13] Kbuild: Rust support

[Connor Kuehl]

On 4/16/21 3:22 PM, Willy Tarreau wrote:
> So it simply does the equivalent of:
> 
>   #define EINVAL -1234
> 
>   struct result {
>      int status;
>      int error;
>   };

Result and Option types are more like a union with a tag that
describes which variant it is.

struct foo_result {
    /* if ok, then access foo_or_err.successful_foo
     *        else, access foo_or_err.error
     */
    bool ok;
    union {
        struct foo successful_foo;
        int error;
    } foo_or_err;
};

> [..]
> 
> So it simply returns a pair of values instead of a single one, which

It will only return 1 value.