In6_addr __align that was not provided

1

I was following Luca Palmieri's book, Zero To Production. I didn't get far before I got this on an Ubuntu VM on VMware:

error: cannot construct in6_addr with struct literal syntax due to private fields
...and other private field __align that was not provided

However, running this on a Debian 10 VM and another Devbian 12 VM on Parallels is just fine. Any ideas?

2

It's impossible to tell what's wrong without further context. What's the full error message, and specifically where and when are you getting it?

3

There's not much else to the error even with full backtrace

rror: cannot construct in6_addr with struct literal syntax due to private fields
--> ~/.cargo/registry/src/index.crates.io-6f17d22bba15001f/socket2-0.5.7/src/sys/unix.rs:1355:5
|
1355 | in6_addr {
| ^^^^^^^^
|
= note: ...and other private field __align that was not provided

Here's the code

use actix_web::{web, App, HttpRequest, HttpServer, Responder};
     async fn greet(req: HttpRequest) -> impl Responder {
     let name = req.match_info().get("name").unwrap_or("World");
    format!("Hello {}!", &name)
}

#[tokio::main]
async fn main() -> Result<(), std::io::Error> {
    HttpServer::new(|| {
        App::new()
         .route("/", web::get().to(greet))
        .route("/{name}", web::get().to(greet))
     })
      .bind("127.0.0.1:8000")?
      .run()
     .await
}
4

Backtrace settings can't affect this error – it's a compile-time error, not a runtime one.

Ah-ha! So it's in the crate socket2. Which in turn imports in6_addr from libc. It's here in libc.

It looks like some platform's libc either contains such a dummy field, or bindgen mistakenly generates an alignment-ensuring field instead of the correct #[repr(align(4))].

You should probably ask the maintainers of the libc crate for more specific help.

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5

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