Public Function AskFaceLoops(ByVal faceTag As NXOpen.Tag) As loop_list()

        Dim loop_t As IntPtr

        NXOpen.Utilities.JAM.StartUFCall()

        Dim errorCode As Integer = UF_MODL_ask_face_loops(faceTag, loop_t)

        NXOpen.Utilities.JAM.EndUFCall()

        If errorCode <> 0 Then

            Throw NXOpen.NXException.Create(errorCode)

        End If

        Dim ptr As IntPtr = loop_t

        Dim loopList As New List(Of loop_list)

        While ptr <> IntPtr.Zero

            Dim loop_list_t As _loop_list = CType(Marshal.PtrToStructure(ptr, GetType(_loop_list)), _loop_list)

            Dim count As Integer

            errorCode = UF_MODL_ask_list_count(loop_list_t.edge_list, count)

            Dim edgeArray(count - 1) As NXOpen.Tag

            For i As Integer = 0 To count - 1

                UF_MODL_ask_list_item(loop_list_t.edge_list, i, edgeArray(i))

            Next

            'UF_MODL_delete_list(loop_list_t.edge_list)

            loopList.Add(New loop_list With {

                         .type = loop_list_t.type,

                         .edge_list = edgeArray})

            ptr = loop_list_t.next

        End While

        UF_MODL_delete_loop_list(loop_t)

        Return loopList.ToArray()

    End Function

    <DllImport("libufun.dll", EntryPoint:="UF_MODL_ask_face_loops", CallingConvention:=CallingConvention.Cdecl, CharSet:=CharSet.Ansi)> _

    Friend Shared Function UF_MODL_ask_face_loops(ByVal face As Tag, <Out> ByRef loop_list As IntPtr) As Integer

    End Function

    <DllImport("libufun.dll", EntryPoint:="UF_MODL_ask_list_count", CallingConvention:=CallingConvention.Cdecl, CharSet:=CharSet.Ansi)> _

    Friend Shared Function UF_MODL_ask_list_count(ByVal list As IntPtr, <Out> ByRef count As Integer) As Integer

    End Function

    <DllImport("libufun.dll", EntryPoint:="UF_MODL_ask_list_item", CallingConvention:=CallingConvention.Cdecl, CharSet:=CharSet.Ansi)> _

    Friend Shared Function UF_MODL_ask_list_item(ByVal list As IntPtr, ByVal index As Integer, <Out> ByRef [object] As Tag) As Integer

    End Function

    <DllImport("libufun.dll", EntryPoint:="UF_MODL_delete_list", CallingConvention:=CallingConvention.Cdecl, CharSet:=CharSet.Ansi)> _

    Public Shared Function UF_MODL_delete_list(ByRef list As IntPtr) As Integer

    End Function

    <DllImport("libufun.dll", EntryPoint:="UF_MODL_delete_loop_list", CallingConvention:=CallingConvention.Cdecl, CharSet:=CharSet.Ansi)> _

    Friend Shared Function UF_MODL_delete_loop_list(ByRef list As IntPtr) As Integer

    End Function

    Friend Structure _loop_list

        Public type As Integer

        Public edge_list As IntPtr

        Public [next] As IntPtr

    End Structure

    Public Structure loop_list

        Public type As Integer 'Peripheral=1, Hole=2, Other=3

        Public edge_list() As NXOpen.Tag

    End Structure

using System;

using System.Collections.Generic;

using  System.Runtime.InteropServices;

    public class AskFaceLoop

    {

        public LoopList[] AskFaceLoops(NXOpen.Tag faceTag)

        {

           System.IntPtr loopT;

            NXOpen.Utilities.JAM.StartUFCall();

            int errorCode = UF_MODL_ask_face_loops(faceTag,out loopT);

            NXOpen.Utilities.JAM.EndUFCall();

            if (errorCode != 0)

            {

                throw NXOpen.NXException.Create(errorCode);

            }

            System.IntPtr ptr = loopT;

            List<LoopList> loopList = new List<LoopList>();

            while (ptr != IntPtr.Zero)

            {

                _loop_list loopListT = (_loop_list)Marshal.PtrToStructure(ptr, typeof(_loop_list));

                int count;

                errorCode = UF_MODL_ask_list_count(loopListT.edge_list,out count);

                NXOpen.Tag[] edgeArray = new NXOpen.Tag[count];

                for (int i = 0; i < count; i++)

                {

                    UF_MODL_ask_list_item(loopListT.edge_list, i,out edgeArray[i]);

                }

                //UF_MODL_delete_list(out loopListT.edge_list);

                loopList.Add(new LoopList{Type = loopListT.type,EdgeList = edgeArray});

                ptr = loopListT.next;

            }

            UF_MODL_delete_loop_list(out loopT);

            return loopList.ToArray();

        }

        [DllImport("libufun.dll", EntryPoint = "UF_MODL_ask_face_loops", CallingConvention = CallingConvention.Cdecl,CharSet = CharSet.Ansi)]

        internal static extern int UF_MODL_ask_face_loops(NXOpen.Tag face, out IntPtr loopList);

        [DllImport("libufun.dll", EntryPoint = "UF_MODL_ask_list_count", CallingConvention = CallingConvention.Cdecl,

            CharSet = CharSet.Ansi)]

        internal static extern int UF_MODL_ask_list_count(IntPtr list, out int count);

        [DllImport("libufun.dll", EntryPoint = "UF_MODL_ask_list_item", CallingConvention = CallingConvention.Cdecl,CharSet = CharSet.Ansi)]

        internal static extern int UF_MODL_ask_list_item(IntPtr list, int index, out NXOpen.Tag @object);

        [DllImport("libufun.dll", EntryPoint = "UF_MODL_delete_list", CallingConvention = CallingConvention.Cdecl,CharSet = CharSet.Ansi)]

        internal static extern int UF_MODL_delete_list(out IntPtr list);

        [DllImport("libufun.dll", EntryPoint = "UF_MODL_delete_loop_list", CallingConvention = CallingConvention.Cdecl,CharSet = CharSet.Ansi)]

        internal static extern int UF_MODL_delete_loop_list(out IntPtr list);

        internal struct _loop_list

        {

            public int type;

            public IntPtr edge_list;

            public IntPtr next;

        }

        public struct LoopList

        {

        /// <summary>

        /// Peripheral=1, Hole=2, Other=3

        /// </summary>

        public int Type;

            public NXOpen.Tag[] EdgeList;

        }

    }