Comparing a ref to null?

[Korporal]

I'm being dumb I'm sure but I have a method that returns a ref to an unmanaged struct.

ref var block_ref = ref SomeMethod();

I want to now write:

if (block_ref == null)
   ...

But I can't get a clean compile no matter what I try...

[CyrusNajmabadi]

@Korporal You might want to consider gitter.im/dotnet/csharplang for quick questions like this. For the above, could you explain how you would get null in the first place in block_ref?

[tannergooding]

You can only get a null ref (that is a ref which is null; rather than a reference to a null) via unsafe means today. For example, using Unsafe.AsRef<T>(null) or via interop code involving ref returns.

Likewise, you need to use the Unsafe class to check if you have a null ref.

[Korporal]

@CyrusNajmabadi - OK You're right, I've not been to gitter and I guess I should take a look.

[Korporal]

You can only get a null ref (that is a ref which is null; rather than a reference to a null) via unsafe means today. For example, using Unsafe.AsRef<T>(null) or via interop code involving ref returns.

Likewise, you need to use the Unsafe class to check if you have a null ref.

@tannergooding

Yes and that's what this is, under the hood the method attempts to get some memory (from outside the AppDomain but inside the process address space) if it is not able to then ordinarily we'd return a null pointer (for example if this in C).

[Korporal]

I've moved to gitter...