"The wayland library could not be loaded" on NixOs with wayland & hyprland

[VirgileHenry]

I'm trying to run winit on NixOs, under wayland and I hit this error :

thread 'main' panicked at src/main.rs:9:39:
called `Result::unwrap()` on an `Err` value: Os(OsError { line: 81, file: "/home/eclipse/.cargo/registry/src/index.crates.io-6f17d22bba15001f/winit-0.29.4/src/platform_impl/linux/wayland/event_loop/mod.rs", error: WaylandError(Connection(NoWaylandLib)) })
stack backtrace:
   0: rust_begin_unwind
             at /rustc/79e9716c980570bfd1f666e3b16ac583f0168962/library/std/src/panicking.rs:597:5
   1: core::panicking::panic_fmt
             at /rustc/79e9716c980570bfd1f666e3b16ac583f0168962/library/core/src/panicking.rs:72:14
   2: core::result::unwrap_failed
             at /rustc/79e9716c980570bfd1f666e3b16ac583f0168962/library/core/src/result.rs:1652:5
   3: core::result::Result<T,E>::unwrap
             at /rustc/79e9716c980570bfd1f666e3b16ac583f0168962/library/core/src/result.rs:1077:23
   4: morpheus::main
             at ./src/main.rs:9:22
   5: core::ops::function::FnOnce::call_once
             at /rustc/79e9716c980570bfd1f666e3b16ac583f0168962/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

(This is with the rust backtrace set to 1, I can run it with full if required.) I'm running this minimal example :

fn main() {
    use winit::{
        event::{Event, WindowEvent},
        window::WindowBuilder,
    };

    let event_loop = winit::event_loop::EventLoop::new().unwrap();
    let _window = WindowBuilder::new().build(&event_loop).unwrap();

    let _result = event_loop.run(move |event, elwt| {
        match event {
            Event::WindowEvent {
                event: WindowEvent::CloseRequested,
                ..
            } => {
                println!("The close button was pressed; stopping");
                elwt.exit();
            },
            _ => ()
        }
    });
}

I've also tried creating the event loop with:

EventLoopBuilder::new().with_wayland().build()

Which have the same effects.

This is all run into an nix shell where I imported the wayland libs:

{ pkgs ? import <nixpkgs> {} }:

pkgs.mkShell {
  buildInputs = with pkgs; [
    wayland
    wayland.dev
  ];
  RUST_BACKTRACE=1;
}

Maybe I'm missing something ? Any help would be helpful.

[kchibisov]

Please, read the documentation on how to use your system. Winit uses dlopen.

[VirgileHenry]

Thanks for the quick reply. I'm trying my best, and I've also tried to use the following flake :

{
  inputs = {
    flake-utils.url = "github:numtide/flake-utils";
    nixpkgs.url = "github:nixos/nixpkgs?ref=release-21.11";
  };

  outputs = {
    self,
    nixpkgs,
    flake-utils,
    ...
  }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };
      in with pkgs; rec {
        devShell = mkShell rec {
          buildInputs = [
            libxkbcommon
            libGL
            # WINIT_UNIX_BACKEND=wayland
            wayland
          ];
          LD_LIBRARY_PATH = "${lib.makeLibraryPath buildInputs}";
          RUST_BACKTRACE="full";
        };
      });
}

Which effectively sets the path for the wayland lib, but with this there is no window at all (the program runs and that's it)

[kchibisov]

(the program runs and that's it)

You must draw on Wayland to have your window shown.

[djmaze]

For people still searching for a solution, I found one which works for me here: https://eu90h.com/wgpu-winit-and-nixos.html