C#

PrincipalContext adPrincipalContext = new PrincipalContext(ContextType.Domain, "********");
UserPrincipal findUser = UserPrincipal.FindByIdentity(adPrincipalContext, Name);
return findUser.EmailAddress;

#region
 
using System;
using System.ComponentModel;
using System.Drawing;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows.Forms;
 
#endregion
 
namespace GlobalHook
{
    public class UserActivityHook
    {
        private const int VmRButton = 0x02;
        private const int VkLControl = 0xA2;
        private const int VkRControl = 0xA3;
        private const int VkControl = 0x11;
        private const int VkSnapshot = 0x2C;
        private const int WhKeyboardLl = 13;
        private const int WhMouseLl = 14;
        private const int WmKeydown = 0x0100;
        private const int WmMousedown =0x0201;
        private static IntPtr kbh_Handle;
        private static IntPtr kbh_Handle1;
 
        private static HookProc KeyboardHookProcedure;
        private static HookProc MouseHookProcedure;     
        private int HMouseHook;        
        private int HKeyboardHook;
 
        #region Windows Function Imports
 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall,
            SetLastError = true)]
        private static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hMod, int dwThreadId);
 
 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall,
            SetLastError = true)]
        public static extern int CallNextHookEx(IntPtr hhk, int nCode, int wParam, IntPtr lParam);
 
 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall,
            SetLastError = true)]
        private static extern int UnhookWindowsHookEx(int idHook);
 
 
        private delegate int HookProc(int nCode, int wParam, IntPtr lParam);
 
        #endregion
 
        #region Windows constants
 
        #endregion
 
        ~UserActivityHook()
        {
            //uninstall hooks and do not throw exceptions
            Stop(true, true, false);
           
        }
 
        public void Start()
        {
 
            if (HMouseHook == 0)
            {
                // Create an instance of HookProc.
                MouseHookProcedure = new HookProc(LowLevelMouseProc);
                //install hook
                HMouseHook = SetWindowsHookEx(WhMouseLl, MouseHookProcedure, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);
                //If SetWindowsHookEx fails.
                if (HMouseHook== 0)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //do cleanup
                    Stop(true, false, false);
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
 
 
 
            // install Keyboard hook only if it is not installed and must be installed
            if (HKeyboardHook == 0)
            {
                // Create an instance of HookProc.
                KeyboardHookProcedure = new HookProc(LowLevelKeyboardProc);
                //install hook
                HKeyboardHook = SetWindowsHookEx(WhKeyboardLl, KeyboardHookProcedure,
                                                 Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),
                                                 0);
                //If SetWindowsHookEx fails.
                if (HKeyboardHook == 0)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //do cleanup
                    Stop(false, true, false);
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
        }
 
        public void Stop()
        {
            Stop(true, true, true);
        }
 
 
        public void Stop(bool uninstallMouseHook, bool uninstallKeyboardHook, bool throwExceptions)
        {
            if (HMouseHook != 0 && uninstallMouseHook)
            {
                //uninstall hook
                int retMouse = UnhookWindowsHookEx(HMouseHook);
                //reset invalid handle
                HMouseHook = 0;
                //if failed and exception must be thrown
                if (retMouse == 0 && throwExceptions)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
 
            //if keyboard hook set and must be uninstalled
            if (HKeyboardHook != 0 && uninstallKeyboardHook)
            {
                //uninstall hook
                int retKeyboard = UnhookWindowsHookEx(HKeyboardHook);
                //reset invalid handle
                HKeyboardHook = 0;
                //if failed and exception must be thrown
                if (retKeyboard == 0 && throwExceptions)
                {
                    //Returns the error code returned by the last unmanaged function called using platform invoke that has the DllImportAttribute.SetLastError flag set. 
                    int errorCode = Marshal.GetLastWin32Error();
                    //Initializes and throws a new instance of the Win32Exception class with the specified error. 
                    throw new Win32Exception(errorCode);
                }
            }
        }
 
 
     
 
        private static int LowLevelKeyboardProc(int nCode, int wParam, IntPtr lParam)
        {
            if (nCode < 0)
            {
                CallNextHookEx(kbh_Handle, nCode, wParam, lParam);
                return 0;
            }
 
            if (wParam == WmKeydown)
            {
                IntPtr kbdll = lParam;
                Kbdllhookstruct kbdllstruct = (Kbdllhookstruct) Marshal.PtrToStructure(kbdll, typeof (Kbdllhookstruct));
 
                if ((kbdllstruct.VkCode == VkSnapshot) || (kbdllstruct.VkCode == VkControl) || (kbdllstruct.VkCode == VkLControl) || (kbdllstruct.VkCode == VkRControl))
                    return -1;
            }
 
            return CallNextHookEx(kbh_Handle, nCode, wParam, lParam);
        }
 
 
 
 
        private static int LowLevelMouseProc(int nCode, int wParam, IntPtr lParam)
        {
            if (nCode < 0)
            {
                CallNextHookEx(kbh_Handle1, nCode, wParam, lParam);
                return 0;
            }
 
            if (wParam == WmMousedown)
            {
                IntPtr msdll = lParam;
                MouseLlHookStruct msdllstruct = (MouseLlHookStruct)Marshal.PtrToStructure(msdll, typeof(MouseLlHookStruct));
 
                if (msdllstruct.MouseData == VmRButton)
                    return -1;
            }
 
            return CallNextHookEx(kbh_Handle1, nCode, wParam, lParam);
        }
 
 
        [StructLayout(LayoutKind.Sequential)]
        private struct Point
        {
            public int X;
            public int Y;
        }
 
 
 
        [StructLayout(LayoutKind.Sequential)]
        private struct MouseLlHookStruct
        {
            public Point Point;
            public int MouseData;
            public int Flags;
            public int Time;
            public int ExtraInfo;
        }
    
 
        #region Nested type: Kbdllhookstruct
 
        [StructLayout(LayoutKind.Sequential)]
        public struct Kbdllhookstruct
        {
            public int VkCode;
            public int ScanCode;
            public int Flags;
            public int Time;
            public int ExtraInfo;
        }
 
        #endregion
    }
}

IntPtr intp = cppFunction ();	// Non-null.

int* pi = (int *) intp;            	// Results in null.

int* pi = (int *) intp.ToPointer ();	// Results in null.


void* vp = intp.ToPointer ();	// Non-null.
int* pi = (int *) vp; 		// Results in null.

[DllImport("vdrdll.dll", EntryPoint = @"?getLineContentsAsArg@@YAXAAPAH@Z")]
public unsafe static extern void getLineContentsAsArg (ref int* lca);

DLLEXPORT void getLineContentsAsArg (int*& lca)
{
    lca = calculateLineContents ();
}