Unhandled Exception: System.DllNotFoundException: Unable to load shared library 'libX11.so.6'

[schonfinkel]

I'm using NixOS and was trying out the Avalonia.FuncUI, I ran into the following error while using it:

# builds fine
$ dotnet build
# breaks
$ dotnet run
Unhandled Exception: System.DllNotFoundException: Unable to load shared library 'libX11.so.6' or one of its dependencies. In order to help diagnose loading problems, consider setting the LD_DEBUG environment variable: liblibX11.so.6.so: cannot open shared object file: No such file or directory
   at Avalonia.X11.XLib.XInitThreads()
   at Avalonia.X11.AvaloniaX11Platform.Initialize(X11PlatformOptions options) in D:\a\1\s\src\Avalonia.X11\X11Platform.cs:line 31
   at Avalonia.Controls.AppBuilderBase`1.Setup() in D:\a\1\s\src\Avalonia.Controls\AppBuilderBase.cs:line 302
   at Avalonia.Controls.AppBuilderBase`1.Start(AppMainDelegate main, String[] args) in D:\a\1\s\src\Avalonia.Controls\AppBuilderBase.cs:line 153
   at NewApp.Program.Main(String[] args) in /home/usul/Github/Horatius/NewApp/Main.fs:line 56

I've managed to track down this error to this repo via this other issue.

Setting LD_DEBUG to lib I get the following as output:

     28790:     find library=liblibX11.so.6 [0]; searching
     28790:      search path=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6:/nix/store/najvrr9mppdrgjh529l79w8px36wn58z-gcc-8.3.0-lib/lib:/nix/store/j3gfzcvb1r5pf0m1zf7zwagb886wpjd8-libunwind-1.3.1/lib:/nix/store/kszi9vwy4ra7zya9gnqg3rgla81mkcx0-util-linux-2.33.2/lib:/nix/store/vb7zl9wdbmgkkfdkzvklh87lv29mxbds-icu4c-64.2/lib:/nix/store/nrnnvdy72487sv5n83qa04lafbl6nbcl-openssl-1.1.1c/lib:/nix/store/62ar9xmrlcnlgmwgfi77xz6bq1180vhi-zlib-1.2.11/lib:/nix/store/g71bqnq5h65aynf8xr2cv54ybfdhplmv-curl-7.65.3/lib                (RUNPATH from file /nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/libcoreclr.so)
     28790:       trying file=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/liblibX11.so.6
     28790:       trying file=/nix/store/najvrr9mppdrgjh529l79w8px36wn58z-gcc-8.3.0-lib/lib/liblibX11.so.6
     28790:       trying file=/nix/store/j3gfzcvb1r5pf0m1zf7zwagb886wpjd8-libunwind-1.3.1/lib/liblibX11.so.6
     28790:       trying file=/nix/store/kszi9vwy4ra7zya9gnqg3rgla81mkcx0-util-linux-2.33.2/lib/liblibX11.so.6
     28790:       trying file=/nix/store/vb7zl9wdbmgkkfdkzvklh87lv29mxbds-icu4c-64.2/lib/liblibX11.so.6
     28790:       trying file=/nix/store/nrnnvdy72487sv5n83qa04lafbl6nbcl-openssl-1.1.1c/lib/liblibX11.so.6
     28790:       trying file=/nix/store/62ar9xmrlcnlgmwgfi77xz6bq1180vhi-zlib-1.2.11/lib/liblibX11.so.6
     28790:       trying file=/nix/store/g71bqnq5h65aynf8xr2cv54ybfdhplmv-curl-7.65.3/lib/liblibX11.so.6
     28790:      search cache=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/etc/ld.so.cache
     28790:      search path=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/lib         (system search path)
     28790:       trying file=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/lib/liblibX11.so.6
     28790:
     28790:     find library=libX11.so.6.so [0]; searching
     28790:      search path=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6:/nix/store/najvrr9mppdrgjh529l79w8px36wn58z-gcc-8.3.0-lib/lib:/nix/store/j3gfzcvb1r5pf0m1zf7zwagb886wpjd8-libunwind-1.3.1/lib:/nix/store/kszi9vwy4ra7zya9gnqg3rgla81mkcx0-util-linux-2.33.2/lib:/nix/store/vb7zl9wdbmgkkfdkzvklh87lv29mxbds-icu4c-64.2/lib:/nix/store/nrnnvdy72487sv5n83qa04lafbl6nbcl-openssl-1.1.1c/lib:/nix/store/62ar9xmrlcnlgmwgfi77xz6bq1180vhi-zlib-1.2.11/lib:/nix/store/g71bqnq5h65aynf8xr2cv54ybfdhplmv-curl-7.65.3/lib                (RUNPATH from file /nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/libcoreclr.so)
     28790:       trying file=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/libX11.so.6.so
     28790:       trying file=/nix/store/najvrr9mppdrgjh529l79w8px36wn58z-gcc-8.3.0-lib/lib/libX11.so.6.so
     28790:       trying file=/nix/store/j3gfzcvb1r5pf0m1zf7zwagb886wpjd8-libunwind-1.3.1/lib/libX11.so.6.so
     28790:       trying file=/nix/store/kszi9vwy4ra7zya9gnqg3rgla81mkcx0-util-linux-2.33.2/lib/libX11.so.6.so
     28790:       trying file=/nix/store/vb7zl9wdbmgkkfdkzvklh87lv29mxbds-icu4c-64.2/lib/libX11.so.6.so
     28790:       trying file=/nix/store/nrnnvdy72487sv5n83qa04lafbl6nbcl-openssl-1.1.1c/lib/libX11.so.6.so
     28790:       trying file=/nix/store/62ar9xmrlcnlgmwgfi77xz6bq1180vhi-zlib-1.2.11/lib/libX11.so.6.so
     28790:       trying file=/nix/store/g71bqnq5h65aynf8xr2cv54ybfdhplmv-curl-7.65.3/lib/libX11.so.6.so
     28790:      search cache=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/etc/ld.so.cache
     28790:      search path=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/lib         (system search path)
     28790:       trying file=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/lib/libX11.so.6.so
     28790:
     28790:     find library=liblibX11.so.6.so [0]; searching
     28790:      search path=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6:/nix/store/najvrr9mppdrgjh529l79w8px36wn58z-gcc-8.3.0-lib/lib:/nix/store/j3gfzcvb1r5pf0m1zf7zwagb886wpjd8-libunwind-1.3.1/lib:/nix/store/kszi9vwy4ra7zya9gnqg3rgla81mkcx0-util-linux-2.33.2/lib:/nix/store/vb7zl9wdbmgkkfdkzvklh87lv29mxbds-icu4c-64.2/lib:/nix/store/nrnnvdy72487sv5n83qa04lafbl6nbcl-openssl-1.1.1c/lib:/nix/store/62ar9xmrlcnlgmwgfi77xz6bq1180vhi-zlib-1.2.11/lib:/nix/store/g71bqnq5h65aynf8xr2cv54ybfdhplmv-curl-7.65.3/lib                (RUNPATH from file /nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/libcoreclr.so)
     28790:       trying file=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/liblibX11.so.6.so
     28790:       trying file=/nix/store/najvrr9mppdrgjh529l79w8px36wn58z-gcc-8.3.0-lib/lib/liblibX11.so.6.so
     28790:       trying file=/nix/store/j3gfzcvb1r5pf0m1zf7zwagb886wpjd8-libunwind-1.3.1/lib/liblibX11.so.6.so
     28790:       trying file=/nix/store/kszi9vwy4ra7zya9gnqg3rgla81mkcx0-util-linux-2.33.2/lib/liblibX11.so.6.so
     28790:       trying file=/nix/store/vb7zl9wdbmgkkfdkzvklh87lv29mxbds-icu4c-64.2/lib/liblibX11.so.6.so
     28790:       trying file=/nix/store/nrnnvdy72487sv5n83qa04lafbl6nbcl-openssl-1.1.1c/lib/liblibX11.so.6.so
     28790:       trying file=/nix/store/62ar9xmrlcnlgmwgfi77xz6bq1180vhi-zlib-1.2.11/lib/liblibX11.so.6.so
     28790:       trying file=/nix/store/g71bqnq5h65aynf8xr2cv54ybfdhplmv-curl-7.65.3/lib/liblibX11.so.6.so
     28790:      search cache=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/etc/ld.so.cache
     28790:      search path=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/lib         (system search path)
     28790:       trying file=/nix/store/6yaj6n8l925xxfbcd65gzqx3dz7idrnn-glibc-2.27/lib/liblibX11.so.6.so
     28790:

Unhandled Exception:      28790:        find library=Microsoft.DiaSymReader.Native.amd64.dll [0]; searching
     28790:      search path=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6:/nix/store/najvrr9mppdrgjh529l79w8px36wn58z-gcc-8.3.0-lib/lib:/nix/store/j3gfzcvb1r5pf0m1zf7zwagb886wpjd8-libunwind-1.3.1/lib:/nix/store/kszi9vwy4ra7zya9gnqg3rgla81mkcx0-util-linux-2.33.2/lib:/nix/store/vb7zl9wdbmgkkfdkzvklh87lv29mxbds-icu4c-64.2/lib:/nix/store/nrnnvdy72487sv5n83qa04lafbl6nbcl-openssl-1.1.1c/lib:/nix/store/62ar9xmrlcnlgmwgfi77xz6bq1180vhi-zlib-1.2.11/lib:/nix/store/g71bqnq5h65aynf8xr2cv54ybfdhplmv-curl-7.65.3/lib                (RUNPATH from file /nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/libcoreclr.so)
     28790:       trying file=/nix/store/89di93ibgvdzykyj4g5xmc4f9i5v6k0k-dotnet-sdk-2.2.401/shared/Microsoft.NETCore.App/2.2.6/Microsoft.DiaSymReader.Native.amd64.dll

Any hints on how to solve it?

[danwalmsley]

does your distro have XServer, and does it have X11 in the $PATH?

[kekekeks]

Most likely caused by NixOS completely ignoring LSB.

You can try messing around with LD_LIBRARY_PATH.

[schonfinkel]

You can try messing around with LD_LIBRARY_PATH.

Thanks for all who posted here. I managed to solve this issue, since I develop in a sandboxed environment it happened that LD_LIBRARY_PATH was not set correctly.

If any Nix posters come here again, this is the shell.nix I'm using now (might have a couple of unnecessary libs on buildInputs, but it works).

{ pkgs ? import ./nix/pinned-nixpkgs.nix {}
, lib ? pkgs.stdenv.lib
}:

pkgs.stdenv.mkDerivation rec {
  name = "dev-shell";

  buildInputs = with pkgs; [
    fontconfig
    mono6
    xorg.libX11
    xorg.libX11.dev
    zlib
  ];

  LD_LIBRARY_PATH = "${lib.makeLibraryPath buildInputs}";
}

[PlumpMath]

~]$ dotnet build ; dotnet run
Microsoft (R) Build Engine version 16.4.0+e901037fe for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

Restore completed in 25.9 ms for /home/user/Proj.csproj.
Proj -> /home/user/Proj/bin/Debug/netcoreapp3.1/Proj.dll

Build succeeded.
0 Warning(s)
0 Error(s)

Time Elapsed 00:00:00.86
Unhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.
at Avalonia.Shared.PlatformSupport.StandardRuntimePlatform.UnmanagedBlob.DoDispose()
at Avalonia.Shared.PlatformSupport.StandardRuntimePlatform.UnmanagedBlob.Finalize()

[schonfinkel]

For anyone looking for a flake to use while developing with this lib, this is what's working for me:

{
  description = ".NET project template";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    utils.url = "github:numtide/flake-utils";
  };

  outputs = inputs@{ nixpkgs, ... }:
    inputs.utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };
        xorgLibs = with pkgs.xorg; [
          libICE
          libSM
          libX11
          libX11.dev
        ];
      in
      rec {
        # `nix develop`
        devShells.default = with pkgs; mkShell {
          buildInputs = [
            dotnet-sdk_8
            fontconfig
            gnumake
            icu
            openssl
          ] ++ xorgLibs;

          shellHook = ''
            export DOTNET_ROOT=${dotnet-sdk}
            export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:${lib.makeLibraryPath ([ fontconfig icu openssl ] ++ xorgLibs) }
          '';
        };
      });
}