I have a function in a library called ProcessSubset(double[] subset){}

I want to slice a larger array and pass it to this function. But I dont want to copy memory for obvious performance reasons, and there is no reason to. Unfortunately c# cant do it.

Now, the subset only needs to be read only. Its just for read only data processing. This basic function doesnt seem supported in .Net. After all, double[] are just pointers to memory so it seems obvious to be able to slice this in a safe way ESPECIALLY if its read only!

so for now, is below the recommended way to do it? Do I then extend this to an extension method on Span?

unsafe
{
    double[] largeArray = new double[1000];
    
    // Fill the array with data as needed

    // Define a pointer to the subset of the array
    fixed (double* p = &largeArray[100]) // Get a pointer to the 100th element
    {
        // Cast it to double[] without copying memory
        double[] subset = new Span<double>(p, 200).ToArray();

        // Call your function
        ProcessSubset(subset);
    }
}