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var arr = new int[100000000];// backed by memory mapped file

zezba9000 wrote:

So again anything you can do in C can be done in C# if you use unsafe code

[DllImport("nativeLib")]
static unsafe extern int* CreateNativeMemoryMappedFile();

unsafe void WriteMemoryMappedFile()
{
  int* nativeMemory = CreateNativeMemoryMappedFile();
  nativeMemory[0] = 123;// this is writing directly from the native buffer (not a copy)
  if (nativeMemory[1] == 321) return;// this is reading directly from the native buffer (not a copy)
}

Quote:

if you think I'm wrong show me how to *create an object* at a specific address in .NET

struct foo {
   int bar;
};

foo* pfoo = VirtualAlloc(..., sizeof(foo));
pfoo->bar=1; // writes to disk
printf("%d",pfoo->bar); // reads from disk.

using System;
using System.Runtime.InteropServices;

using SIZE_T = System.IntPtr;
using DWORD = System.UInt32;

namespace TestNet
{
	[StructLayout(LayoutKind.Sequential)]
	struct Foo
	{
		public int bar;
	}

	static class Program
	{
		[DllImport("Kernel32.dll")]
		private static unsafe extern void* VirtualAlloc(void* lpAddress, SIZE_T dwSize, DWORD flAllocationType, DWORD flProtect);

		private const DWORD MEM_COMMIT = 0x00001000;
		private const DWORD PAGE_READWRITE = 0x04;

		static unsafe void Main(string[] args)
		{
			Foo* pfoo = (Foo*)VirtualAlloc((void*)0, (SIZE_T)sizeof(Foo), MEM_COMMIT, PAGE_READWRITE);
			pfoo->bar = 1; // writes to disk
			Console.WriteLine(pfoo->bar.ToString()); // reads from disk.
		}
	}
}