How can global function exist in C#?

Question

How can global function exist in C# when everything is defined inside a class? I was reading the documentation of OpCodes.Call at MSDN, and was surprised to see the followin

Answer 1

At the Build 2014 conference it was announced that from Roslyn onwards, you can import static methods from types by the using TypeName; directive, so that instead of having to use System.Math.Min(...) you can do:

using System.Math;
...
var z = Min(x,y);

---

Note: by the time of release this became:

using static System.Math;

Answer 2

Because System.Reflection.Emit.OpCodes.Call isn't about C#. It's about emitting IL opcodes. In IL, there are features that are not available in C#. Global functions is one of those features.

Answer 3

C# does not support all features of MSIL. Global functions is one of them. VB.Net, F#, IronPython or some other language likley to use this and other features that are not generated by C# compiler.

Answer 4

I'm just overwriting my previous answer...

Here is what each look like in IL DASM with their associated codes:

// Static Method
IL_0001:  call       void testapp.Form1::Test()

// Instance Method
IL_0001:  call       instance void testapp.Form1::Test()

// Virtual Method
IL_0001:  callvirt   instance void testapp.Form1::Test()

// Global Function
IL_0000:  call       void testapp.Test()

So to answer your question, there isn't a direct way to generate the metadata token in the last method for C#. I had to create the last in C++.

Answer 5

The documentation you are referring to is for .net. C# does not cater for global functions but .net does.

Answer 6

You can't have global functions in C#, it's just not part of the language. You have to use a static method on some class of your choosing to get similar functionality.

However C# is not the only language that uses the CLR. One can write Managed C++, which can have global functions.