[.NETCF] How to declare memory-mapped file API with C# in WinCE

public class WinCEConst
{
    public const UInt32 STANDARD_RIGHTS_REQUIRED = 0x000F0000;
    public const UInt32 SECTION_QUERY = 0x0001;
    public const UInt32 SECTION_MAP_WRITE = 0x0002;
    public const UInt32 SECTION_MAP_READ = 0x0004;
    public const UInt32 SECTION_MAP_EXECUTE = 0x0008;
    public const UInt32 SECTION_EXTEND_SIZE = 0x0010;
    public const UInt32 SECTION_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED SECTION_QUERY|
        SECTION_MAP_WRITE|
        SECTION_MAP_READ|
        SECTION_MAP_EXECUTE|
        SECTION_EXTEND_SIZE);
    public const UInt32 FILE_MAP_ALL_ACCESS = SECTION_ALL_ACCESS;

    public static IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);

    public const int PAGE_READWRITE = 0x04;
    public const int PAGE_READONLY = 0x02;
    public const int FILE_MAP_READ = 0x0004;
    public const int FILE_MAP_WRITE = 0x0002;
}

public class WinCE
{
    // * WinCE using coredll.dll
    // * Windows using keneral32.dll

    [DllImport("Coredll.dll", SetLastError = true, CharSet = CharSet.Auto)]
    public static extern IntPtr CreateFileMapping(
        IntPtr hFile,
        object lpFileMappingAttributes,
        uint flProtect,
        uint dwMaximumSizeHigh,
        uint dwMaximumSizeLow,
        string lpName);

    public static IntPtr OpenFileMapping(uint dwDesiredAccess, bool bInheritHandle, string lpName)
    {
        IntPtr t_pHandle = CreateFileMapping(new IntPtr(-1), null,
        WinCEConst.PAGE_READWRITE, 0, 0, lpName);
        return t_pHandle;
    }

    [DllImport("Coredll.dll", SetLastError = true)]
    public static extern bool CloseHandle(IntPtr hObject);

    [DllImport("Coredll.dll", SetLastError = true)]
    public static extern IntPtr MapViewOfFile(
        IntPtr hFileMappingObject,
        uint dwDesiredAccess,
        uint dwFileOffsetHigh,
        uint dwFileOffsetLow,
        uint dwNumberOfBytesToMap);

    [DllImport("Coredll.dll", SetLastError = true)]
    public static extern bool UnmapViewOfFile(IntPtr lpBaseAddress);
}

If we want to communicate information at different process , we can use memory-mapped file.

If we want to use memory-mapped file in C#, we must use DllImport to declare API.

Memory-mapped files (MMFs) offer a unique memory management feature that allows applications to access files on disk in the same way they access dynamic memory—through pointers. With this capability you can map a view of all or part of a file on disk to a specific range of addresses within your process's address space. And once that is done, accessing the content of a memory-mapped file is as simple as dereferencing a pointer in the designated range of addresses.

You can see the reference for Win32 on MSDN.