I’ve been a long-time Omnisharp fan and it is kinda important that I can work on C# code somewhat productively in order to get anywhere with my project. Nevertheless, some recent update of ommisharp-emacs broke my setup and hence I set out in order to fix it.

Since it was quite a lengthy process to figure out what to do, I’ll use this as a little note to myself on how to get the setup straight:

  1. Use omnisharp-mono.tar.gz release if you are not running on dotnet core yet.
  2. Install it into a proper location, e.g. ~/.emacs.d/omnisharp-roslyn-mono/.
  3. Locate System.Native.so: 
    $ locate System.Native.so
/usr/share/dotnet/shared/Microsoft.NETCore.App/1.0.4/System.Native.so
/usr/share/dotnet/shared/Microsoft.NETCore.App/1.1.1/System.Native.so
  4. Put a copy of the file next to OmniSharp.exe (I used the 1.0.4 version, the other one didn’t seem to work) and call it libSystem.Native.so (see this issue on GitHub).
  5. Add a script that runs OmniSharp.exe with mono from its absolute path and call it omnisharp.sh: 
    #!/bin/bash
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
mono $DIR/OmniSharp.exe "$@"
  6. Tell Emacs to run this script when starting OmniSharp: 
    (setq omnisharp-server-executable-path "~/.emacs.d/omnisharp-roslyn-mono/omnisharp.sh")
  7. Make it start automatically when opening a .cs file, if it is not already running.

This used to be much easier. I hope that writing this down will spare me from having to figure all this stuff out again a second time.