You can use any data type for lParam if it is 'ref', since as a 'ref' it is already being passed as a pointer.

The PTIMERAPCROUTINE type defines a pointer to this callback function. TimerAPCProc is a placeholder for the application-defined function name.

''' The PTIMERAPCROUTINE type defines a pointer to this callback function. TimerAPCProc is a placeholder for the application-defined function name.

The TIMERPROC type defines a pointer to this callback function. TimerProc is a placeholder for the application-defined function name

    ref IntPtr ppProcessInfo, // pointer to array of WTS_PROCESS_INFO

    ref Int32  pCount     // pointer to number of processes

        'ProcessName is merely a pointer to the string - convert it to the full string...

        'Now move on the pointer to the next member of the array...

    EntryPoint:="WTSEnumerateSessions", _

    Dim pWinStationName As String ' integer LPTSTR - Pointer to a null-terminated string containing the name of the WinStation for this session

    Dim pWinStationName As String ' integer LPTSTR - Pointer to a null-terminated string containing the name of the WinStation for this session

    EntryPoint:="WTSEnumerateSessions", _

/// <param name="ppBuffer">Pointer to a variable that receives a pointer to the requested information. The format and contents of the data depend on the information class specified in the <see cref="WTSInfoClass"/> parameter.

/// <param name="pBytesReturned">Pointer to a variable that receives the size, in bytes, of the data returned in ppBuffer.</param>

    private static extern void WTSFreeMemory(IntPtr pointer);

    /// <param name="ppBuffer">Pointer to a variable that receives a pointer to the requested information. The format and contents of the data depend on the information class specified in the <see cref="WTSInfoClass"/> parameter.

    /// <param name="pBytesReturned">Pointer to a variable that receives the size, in bytes, of the data returned in ppBuffer.</param>

            /// <param name="memory">Pointer to the memory to free.</param>

        //This is a pointer to string...

    Dim ProcessName As Int32    'This is a pointer to string...which is not right for 64 bits...

[DllImport("CRYPT32.DLL", EntryPoint = "CertAddEncodedCertificateToStore", CharSet = CharSet.Auto, SetLastError = true)]

[DllImport("CRYPT32.DLL", EntryPoint="CertCloseStore", CharSet=CharSet.Auto, SetLastError=true)]

     [DllImport("Crypt32.DLL", EntryPoint="CertCreateCertificateContext",

This function actually returns a CTL_CONTEXT pointer (please see CTL_CONTEXT on this site)

[DllImport("CRYPT32.DLL", EntryPoint="CertEnumCertificatesInStore", CharSet=CharSet.Auto, SetLastError=true)]

     <DllImport("crypt32.dll", EntryPoint:="CertEnumCertificatesInStore", CharSet:=CharSet.Auto, SetLastError:=True)> _

[DllImport("crypt32.dll", EntryPoint = "CertGetNameString", CharSet = CharSet.Auto, SetLastError = true)]

    [DllImport("crypt32.dll", SetLastError = true, EntryPoint = "CertNameToStr")]

[DllImport("CRYPT32.DLL", EntryPoint="CertOpenStore", CharSet=CharSet.Auto, SetLastError=true)]

[DllImport("CRYPT32.DLL", EntryPoint="CertOpenStore", CharSet=CharSet.Auto, SetLastError=true)]

    [DllImport("CRYPT32.DLL", EntryPoint = "CryptQueryObject", CharSet = CharSet.Auto, SetLastError = true)]

        rgpbToBeSigned,       // Pointer to signed BLOB.

    /// The *argp parameter is a pointer to an unsigned long value.

        SIO_GET_EXTENSION_FUNCTION_POINTER = -939524090,

        SIO_MULTIPOINT_LOOPBACK = -2013265911,

        /// The *argp parameter is a pointer to an unsigned long value.

    [DllImport("Ws2_32.dll", CharSet = CharSet.Unicode, EntryPoint = "InetNtopW")]

    [DllImport("Ws2_32.dll", CharSet = CharSet.Unicode, EntryPoint = "InetNtopW")]

    [DllImport("Ws2_32.dll", CharSet = CharSet.Unicode, EntryPoint = "InetPtonW")]

    [DllImport("Ws2_32.dll", CharSet = CharSet.Unicode, EntryPoint = "InetPtonW")]

        /* An optional pointer to a set of sockets to be checked for readability. */

        /* An optional pointer to a set of sockets to be checked for writability. */

        /* An optional pointer to a set of sockets to be checked for errors. */

[DllImport("ws2_32.dll", EntryPoint="sendto")]

        /// Receive ECN codepoints in the IP header

        /// Receive ECN codepoints in the IP header.

    [DllImport("Ws2_32.dll", CharSet = CharSet.Unicode, EntryPoint = "WSAAddressToStringW")]

    [DllImport("Ws2_32.dll", CharSet = CharSet.Unicode, EntryPoint = "WSAAddressToStringW")]

        /// The main entry point for the application.

              EntryPoint = "WSAStringToAddressW" ) ]

• addressStrings: A pointer to the string that contains the network address to convert.

• socketAddress: A pointer to a buffer that is filled with a sockaddr structure for the address string if the function succeeds.

• socketAddressSize: A pointer to the length, in bytes, of the buffer pointed to by the lpAddress parameter.

<DllImport("rasapi32.dll", EntryPoint:="RasEnumEntries", CharSet:=CharSet.Auto)> _

/// <param name="lpszPhonebook">Pointer to a null-terminated string that specifies the full path and file name of a phone-book (PBK) file.

/// <param name="lpszEntry">Pointer to a null-terminated string that specifies an entry name.

/// <param name="lpRasEntry">Pointer to the RASENTRY structure that specifies the connection data to associate with the phone-book entry.</param>

[DllImport("hhctrl.ocx", SetLastError=true, EntryPoint = "HtmlHelpW", CharSet = CharSet.Unicode)]

<DllImport("hhctrl.ocx", SetLastError:=True, EntryPoint:="HtmlHelpW", CharSet:=CharSet.Unicode)> _

[DllImport("hhctrl.ocx", SetLastError = true, EntryPoint = "HtmlHelpW", CharSet = CharSet.Unicode)]

    class POINT

        public POINT()

        public POINT(int x, int y)

        internal POINT pt;

    Point current_cursor_location = Control.MousePosition;

    param.pt = new POINT(current_cursor_location.X, current_cursor_location.Y);

        ' pointer

     /// <summary>Sets new extra information that is private to the application, such as handles or pointers.</summary>

    /// the lpszName parameter is a pointer to a null-terminated string that contains the name of the image resource.

    ''' the lpszName parameter is a pointer to a null-terminated string that contains the name of the image resource.

        public const int DfsCantCreateJunctionPoint = 2669;

    public static PropertyKey PKEY_AudioEndpoint_FormFactor = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 0);

    public static PropertyKey PKEY_AudioEndpoint_ControlPanelPageProvider = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 1);

    public static PropertyKey PKEY_AudioEndpoint_Association = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 2);

    public static PropertyKey PKEY_AudioEndpoint_PhysicalSpeakers = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 3);

    public static PropertyKey PKEY_AudioEndpoint_GUID = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 4);

    public static PropertyKey PKEY_AudioEndpoint_Disable_SysFx = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 5);

    public static PropertyKey PKEY_AudioEndpoint_FullRangeSpeakers = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 6);

    public static PropertyKey PKEY_AudioEndpoint_Supports_EventDriven_Mode = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 7);

    public static PropertyKey PKEY_AudioEndpoint_JackSubType = new PropertyKey(  0x1da5d803, 0xd492, 0x4edd, 0x8c, 0x23, 0xe0, 0xc0, 0xff, 0xee, 0x7f, 0x0e, 8);

    public static PropertyKey WPD_APPOINTMENT_LOCATION = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 3);

    public static PropertyKey WPD_APPOINTMENT_TYPE = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 7);

    public static PropertyKey WPD_APPOINTMENT_REQUIRED_ATTENDEES = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 8);

    public static PropertyKey WPD_APPOINTMENT_OPTIONAL_ATTENDEES = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 9);

    public static PropertyKey WPD_APPOINTMENT_ACCEPTED_ATTENDEES = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 10);

    public static PropertyKey WPD_APPOINTMENT_RESOURCES = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 11);

    public static PropertyKey WPD_APPOINTMENT_TENTATIVE_ATTENDEES = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 12);

    public static PropertyKey WPD_APPOINTMENT_DECLINED_ATTENDEES = new PropertyKey(0xF99EFD03, 0x431D, 0x40D8, 0xA1, 0xC9, 0x4E, 0x22, 0x0D, 0x9C, 0x88, 0xD3, 13);

    public static PropertyKey PKEY_AudioEndPoint_Interface = new PropertyKey("a45c254e-df1c-4efd-8020-67d146a850e0", 2);

    public static PropertyKey PKEY_AudioEndPoint_DisableSysFx = new PropertyKey("1da5d803-d492-4edd-8c23-e0c0ffee7f0e", 5);

    public static PropertyKey PKEY_Endpoint_Enable_LFX = new PropertyKey("a988f78b-07b6-4f47-9c9f-25409534cdee", 0);

    public static PropertyKey PKEY_Endpoint_Enable_LFX_BEAMFORMING = new PropertyKey("818d3b4c-2bbf-40e9-a438-9361b0ffc427", 0);

    public static PropertyKey PKEY_Endpoint_Enable_LFX_AEC = new PropertyKey("7996efb2-29c1-4898-be83-4a3646e06fac", 0);

    public static PropertyKey PKEY_Endpoint_Enable_GFX = new PropertyKey("7f73d4e1-91e3-4490-9fba-5e86680a5748", 0);

    public static PropertyKey PKEY_Endpoint_Disable_AC3 = new PropertyKey("b3f8fa53-0004-438e-9003-51a46e139bfc", 5);

    public static PropertyKey PKEY_Endpoint_Name = new PropertyKey("b3f8fa53-0004-438e-9003-51a46e139bfc", 6);

    public static PropertyKey PKEY_AudioEndPoint_Type = new PropertyKey("1da5d803-d492-4edd-8c23-e0c0ffee7f0e", 0);

    public static PropertyKey PKEY_AudioEndpoint_Ext_UiClsid  = new PropertyKey("{1DA5D803-D492-4EDD-8C23-E0C0FFEE7F0E}",1);

    public static PropertyKey Render_AudioEndpoint_Flag = new PropertyKey("b3f8fa53-0004-438e-9003-51a46e139bfc", 3);

    public static PropertyKey Render_AudioEndpoint_Flag2 = new PropertyKey("b3f8fa53-0004-438e-9003-51a46e139bfc", 4);

    public static Guid FMTID_Endpoint_Info = new Guid("a45c254e-df1c-4efd-8020-67d146a850e0");

    public const int FOF_NORECURSEREPARSE       = 0x8000;  // treat reparse points as objects, not containers

    public const int FOF_NORECURSEREPARSE       = 0x8000;  // treat reparse points as objects, not containers

UInt32 STATUS_BREAKPOINT                 = (UInt32)0x80000003L;

private const uint FILE_FLAG_OPEN_REPARSE_POINT  = 0x00200000;

public const int FSCTL_QUERY_RETRIEVAL_POINTERS = 0x0009003b;

public const int FSCTL_GET_RETRIEVAL_POINTERS = 0x00090073;

public const int FSCTL_SET_REPARSE_POINT = 0x000900a4;

public const int FSCTL_GET_REPARSE_POINT = 0x000900a8;

public const int FSCTL_DELETE_REPARSE_POINT = 0x000900ac;

        /// An attempt was made to move the file pointer before the beginning of the file.

        /// The file pointer cannot be set on the specified device or file.

        /// The point passed to GetMouseMovePoints is not in the buffer.

        public const int ERROR_POINT_NOT_FOUND = 1171;

        /// The network transport endpoint already has an address associated with it.

        /// An address has not yet been associated with the network endpoint.

        /// No service is operating at the destination network endpoint on the remote system.

        /// The endpoint format is invalid.

        public const int RPC_S_INVALID_ENDPOINT_FORMAT = 1706;

        /// No endpoint was found.

        public const int RPC_S_NO_ENDPOINT_FOUND = 1708;

        /// The endpoint cannot be created.

        public const int RPC_S_CANT_CREATE_ENDPOINT = 1720;

        /// The endpoint is a duplicate.

        public const int RPC_S_DUPLICATE_ENDPOINT = 1740;

        /// The server endpoint cannot perform the operation.

        /// There are no more endpoints available from the endpoint mapper.

        /// A floating-point operation at the RPC server caused a division by zero.

        /// A floating-point underflow occurred at the RPC server.

        /// A floating-point overflow occurred at the RPC server.

        /// A null reference pointer was passed to the stub.

        public const int RPC_X_NULL_REF_POINTER = 1780;

        /// The endpoint mapper database entry could not be created.

        /// The file or directory is not a reparse point.

        public const int ERROR_NOT_A_REPARSE_POINT = 4390;

        /// The reparse point attribute cannot be set because it conflicts with an existing attribute.

        /// The data present in the reparse point buffer is invalid.

        /// The tag present in the reparse point buffer is invalid.

        /// There is a mismatch between the tag specified in the request and the tag present in the reparse point.

        /// No checkpoint record was found in the cluster log.

        public const int ERROR_CLUSTERLOG_CHKPOINT_NOT_FOUND = 5032;

        public const int ERROR_DS_ALIAS_POINTS_TO_ALIAS = 8336;

        /// The checkpoint with the PDC could not be taken because there too many modifications being processed currently.

        public const int ERROR_DS_NO_CHECKPOINT_WITH_PDC = 8551;

        /// Could not create pointer (PTR) record.

        /// The system detected an invalid pointer address in attempting to use a pointer argument in a call.

        /// The private manifest probed has crossed reparse-point-associated path

        public const int ERROR_SXS_PRIVATE_MANIFEST_CROSS_PATH_WITH_REPARSE_POINT = 14020;

        /// Invalid pointer

        public const int E_POINTER = (int)(0x80000005 - 0x100000000);

        /// An invalid root block pointer was specified

        /// An allocation chain contained an invalid link pointer

        /// Invalid pointer error.

        public const int STG_E_INVALIDPOINTER = (int)(0x80030009 - 0x100000000);

        /// The operation involving unsigned file copying was rolled back, so that a system restore point could be set.

        public const int SPAPI_E_SET_SYSTEM_RESTORE_POINT = (int)(0x800F0236 - 0x100000000);

        /// There was an error trying to set the smart card file object pointer.

private const uint FILE_ATTRIBUTE_REPARSE_POINT       = 0x00000400;

' Why would you use int16 for a loop counter and for a pointer offset ?

    public DHCP_CLIENT_UID ClientHardwareAddress; //no pointer -> structure !!

    public DATE_TIME ClientLeaseExpires; //no pointer -> structure !!

    public DHCP_HOST_INFO OwnerHost; //no pointer -> structure

ResumeHandle - [in,out] Pointer to a DHCP_RESUME_HANDLE value that identifies the enumeration operation. Initially, this value should be zero, with a successful call returning the handle value used for subsequent enumeration requests. For example, if PreferredMaximum is set to 100, and 200 subnet addresses are stored on the server, the resume handle can be used after the first 100 subnets are retrieved to obtain the next 100 on a subsequent call, and so forth.

EnumInfo - [out] Pointer to a DHCP_IP_ARRAY [IntPtr] structure that contains the subnet IDs available on the DHCP server. If no subnets are defined, this value will be null.

ElementsRead - [out] Pointer to a DWORD value that specifies the number of subnet addresses returned in EnumInfo.

ElementsTotal - [out] Pointer to a DWORD value that specifies the number of subnets defined on the DHCP server that have not yet been enumerated

/// <param name="ClientInfo">[out] Pointer to a DHCP_CLIENT_INFO structure that contains information describing the DHCP client that most closely matches the provided search parameters. If no client is found, this parameter will be null.</param>

    ''' <param name="ClientInfo">[out] Pointer to a DHCP_CLIENT_INFO structure that contains information describing the DHCP client that most closely matches the provided search parameters. If no client is found, this parameter will be null.

static extern void DhcpRpcFreeMemory(IntPtr BufferPointer);

Declare Unicode Sub DhcpRpcFreeMemory Lib "Dhcpsapi" (ByVal BufferPointer As IntPtr)

• "a+" - Open a file for reading and appending. All writing operations are performed at the end of the file, protecting the previous content to be overwritten. You can reposition (fseek, rewind) the internal pointer to anywhere in the file for reading, but writing operations will move it back to the end of file. The file is created if it does not exist.

[DllImport("msvcrt.dll", EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]

    <DllImport("msvcrt.dll", EntryPoint:="memcpy", CallingConvention:=CallingConvention.Cdecl)> _

System.Buffer.BlockCopy, Marshal.Copy and Array.Copy provide similar services, but require one or two managed arrays instead of pointers.

[DllImport("msvcrt.dll", EntryPoint = "memset", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]

<DllImport("msvcrt.dll", EntryPoint := "memset", CallingConvention := CallingConvention.Cdecl, SetLastError := False)> _

dest - Pointer to destination.

        FileReparsePointInformation

        FileReparsePointInformation,      // 33

        FileReparsePointInformation,        // 33

            FileAttributes.ReparsePoint,

        //Return pointer to PEB base address

        return infoPtr;//don't forget to free the pointer with Marshal.FreeHGlobal after you're done with it

        Marshal.FreeHGlobal(infoPtr);//free pointer when not Successful

/// <param name="Size">The allocation size of the buffer pointed to by Info</param>

        Marshal.FreeHGlobal(infoPtr);  //free pointer when not Successful

        UNDNAME_NO_THROW_SIGNATURES      = (0x0100),  // Disable expansion of 'throw-signatures' for functions and pointers to functions

/// For use with ChildWindowFromPointEx

public enum WindowFromPointFlags

Enum ChildWindowFromPointFlags

        /// Retrieves the dimensions, in tenths of a millimeter, of each supported paper size. The pOutput buffer receives an array of POINT structures. Each structure contains the width (x-dimension) and length (y-dimension) of a paper size as if the paper were in the DMORIENT_PORTRAIT orientation. The return value indicates the number of entries in the array.

    FILE_DEVICE_POINT_OF_SERVICE = 0x54,

    FILE_DEVICE_POINT_OF_SERVICE = &H54

    /// <summary> Control processes the message in the MSG structure that lParam points to. </summary>