Sune,

   Well, you could access the memory block that is used by the C module if
you REALLY wanted to, but generally, the way it works is that you are going
to call the API through the P/Invoke layer, which is going to be responsible
for marshaling the .NET types to the unmanaged module and back.

You asked the same question in the Java group. Do you need the
solution in C# or Java or both ?

Pure managed C# can not overwrite memory.

You will need to call unmanaged (native) code to do what
you want.

And that code can overwrite memory.

If you want to have your C# code access global memory
managed by the C code, then I think you can use only your C# code and
native code provided by Microsoft.

See below for a code snippet (some C# code that communicates
via some Delphi code via global memory.

Arne

==============================

using System;
using System.Runtime.InteropServices;

class MainClass
{
    const int PAGE_READONLY = 0x0002;
    const int PAGE_READWRITE = 0x0004;
    const int PAGE_EXECUTE = 0x0010;
    const int PAGE_EXECUTE_READ = 0x0020;
    const int PAGE_EXECUTE_READWRITE = 0x0040;
    const int PAGE_GUARD = 0x0100;
    const int PAGE_NOACCESS = 0x0001;
    const int PAGE_NOCACHE = 0x0200;
    const int FILE_MAP_COPY = 0x0001;
    const int FILE_MAP_WRITE = 0x0002;
    const int FILE_MAP_READ = 0x0004;
    const int FILE_MAP_ALL_ACCESS = 0x001F;

    [StructLayout( LayoutKind.Sequential )]
    class SECURITY_ATTRIBUTES
    {
        //int nLength;
        //int lpSecurityDescriptor;
        //int bInheritHandle;
    }

    [DllImport("kernel32.dll")]
    static extern int CreateFileMappingA ( uint hFile,
                                           SECURITY_ATTRIBUTES
lpFileMappigAttributes,
                                           int flProtect,
                                           int dwMaximumSizeHigh,
                                           int dwMaximumSizeLow,
                                           string lpName);

    [DllImport("kernel32.dll")]
    static extern IntPtr MapViewOfFile ( int hFileMappingObject,
                                         int dwDesiredAccess,
                                         int dwFileOffsetHigh,
                                         int dwFileOffsetLow,
                                         int dwNumberOfBytesToMap);

    [DllImport("kernel32.dll")]
    static extern int UnmapViewOfFile (IntPtr lpBaseAddress);

    [DllImport("kernel32.dll")]
    static extern int CloseHandle ( int hObject);

    public static void Main(string[] args)
    {
        int mem = CreateFileMappingA(0xFFFFFFFF, null, PAGE_READWRITE,
0, 8192, "GBLMEM");
        IntPtr data = MapViewOfFile(mem, FILE_MAP_WRITE, 0, 0, 8192);
        Console.WriteLine("Run Delphi program and press enter");
        Console.ReadLine();
        int[] data2 = new int[2048];
        Marshal.Copy( data, data2, 0, 3 );
        UnmapViewOfFile(data);
        CloseHandle(mem);
        Console.WriteLine(data2[0]);
        Console.WriteLine(data2[1]);
        Console.WriteLine(data2[2]);
    }
}