Mono

From ArchWiki

From Wikipedia:

Mono is a [...] project to create a .NET Framework-compatible set of tools including, among others, a C# compiler and a Common Language Runtime.

Installation

Install the mono package.

If you need VisualBasic.Net support you have to install the VisualBasic.Net interpreter with the package mono-basicAUR.

Note: Installing the package stores certificate authorities in /usr/share/.mono/certs/Trust/ but removing the package does not remove them.[1]

Running Mono applications

You can execute Mono binaries by calling mono manually: 

$ mono programsname.exe

You can also execute Mono binaries directly, just like native binaries: 

$ chmod 755 exefile.exe
$ ./exefile.exe

Testing Mono

Make a new file: 

test.cs
using System;

public class Test {
 public static void Main(string[] args) {
  Console.WriteLine("Hello World!");
 }
}

Then run: 

$ mcs test.cs
$ mono test.exe
Hello world!

Development

OmniSharp provides .NET/Mono development plugins/integrations for several editors, including Vim, Emacs, and Visual Studio Code. Alternatively, you can install the riderAUR IDE.

If you want the API documentation browser and some testing and development tools you have to install mono-tools.

Troubleshooting

I get an error when I try to run Mono binaries directly: "cannot execute binary file"

The binfmt_misc handler for Mono has not yet been set up, as explained in detail on the Mono Project website.

To fix this, restart the systemd-binfmt service.

I get an TLS handshake (or similar certificate based) error

Try mozroots --import --ask-remove which should update monos certificates. mozroots is part of the mono package.

I get an error when building fsharp: "System.TypeInitializationException: The type initializer for 'System.Console' threw an exception"

There is a recent bug in mcs that is used to build fsharp. A workaround is to use export TERM=xterm, as detailed here [2]

See also