Are stack based arrays possible in C#?

Question

Let's say, hypothetically (read: I don't think I actually need this, but I am curious as the idea popped into my head), one wanted an array of memory set aside locally on the stack, not on the heap. For instance, something like this:

private void someFunction()
{
    int[20] stackArray; //C style; I know the size and it's set in stone
}

I'm guessing the answer is no. All I've been able to find is heap based arrays. If someone were to need this, would there be any workarounds? Is there any way to set aside a certain amount of sequential memory in a "value type" way? Or are structs with named parameters the only way (like the way the Matrix struct in XNA has 16 named parameters (M11-M44))?

Answer 1

What you want is stackalloc; unfortunately, you can only use this in unsafe code, which means it won't run in a limited permissions context.

You could also create a struct with the necessary number of variables in it for each element type, but you would need a new type for each size of 'array' you wanted to use

Answer 2

You can create a fixed array in a structure or class (use the C# fixed keyword for this). This will do exactly what you need. The structure needs to be defined as unsafe to be able to do this.