Question: I have [this](http://dl.dropboxusercontent.com/s/kif6wdoq5txebcr/download?dl=1) file, and I have absolutely no idea what kind of file it is.

When I open it in Notepad++ it reads as

```
ð    X      döS   

```

**or**

[![](https://i.stack.imgur.com/SDdon.png)](https://i.stack.imgur.com/SDdon.png)  

(source: [gyazo.com](http://gyazo.com/d156217b86512943d494f908b74c050e.png))

How can I figure out what language this is?

Answer: 
you might want to try using netmq (<https://github.com/zeromq/netmq>), is a 100% C# port of zeromq and might be easier to use then calling pinvoke.
Is libzmq.dll next to your executable in the build output directory ?

The clrzmq NuGet package includes a PowerShell install script to set the build action for the libzmq.dll so it is always copied to the output directory. If you added the NuGet package on the Mac then the PowerShell script will not be run. So you will need to set the build action manually.

libzmq.dll seems to be a native dll compiled for Windows so it will not work on the Mac. So it looks like you will have to compile clrzmq on the Mac.