System.Net.Sockets.SocketPal.Receive C# (CSharp) Метод

        private static unsafe int Receive(SafeCloseSocket socket, SocketFlags flags, IList<ArraySegment<byte>> buffers, byte[] socketAddress, ref int socketAddressLen, out SocketFlags receivedFlags, out Interop.Error errno)
        {
            int available;
            errno = Interop.Sys.GetBytesAvailable(socket, &available);
            if (errno != Interop.Error.SUCCESS)
            {
                receivedFlags = 0;
                return -1;
            }
            if (available == 0)
            {
                // Always request at least one byte.
                available = 1;
            }

            // Pin buffers and set up iovecs.
            int maxBuffers = buffers.Count;
            var handles = new GCHandle[maxBuffers];
            var iovecs = new Interop.Sys.IOVector[maxBuffers];

            int sockAddrLen = 0;
            if (socketAddress != null)
            {
                sockAddrLen = socketAddressLen;
            }

            long received = 0;
            int toReceive = 0, iovCount = maxBuffers;
            try
            {
                for (int i = 0; i < maxBuffers; i++)
                {
                    ArraySegment<byte> buffer = buffers[i];
                    handles[i] = GCHandle.Alloc(buffer.Array, GCHandleType.Pinned);
                    iovecs[i].Base = &((byte*)handles[i].AddrOfPinnedObject())[buffer.Offset];

                    int space = buffer.Count;
                    toReceive += space;
                    if (toReceive >= available)
                    {
                        iovecs[i].Count = (UIntPtr)(space - (toReceive - available));
                        toReceive = available;
                        iovCount = i + 1;
                        break;
                    }

                    iovecs[i].Count = (UIntPtr)space;
                }

                // Make the call.
                fixed (byte* sockAddr = socketAddress)
                fixed (Interop.Sys.IOVector* iov = iovecs)
                {
                    var messageHeader = new Interop.Sys.MessageHeader {
                        SocketAddress = sockAddr,
                        SocketAddressLen = sockAddrLen,
                        IOVectors = iov,
                        IOVectorCount = iovCount
                    };

                    errno = Interop.Sys.ReceiveMessage(socket, &messageHeader, flags, &received);
                    receivedFlags = messageHeader.Flags;
                    sockAddrLen = messageHeader.SocketAddressLen;
                }
            }
            finally
            {
                // Free GC handles.
                for (int i = 0; i < iovCount; i++)
                {
                    if (handles[i].IsAllocated)
                    {
                        handles[i].Free();
                    }
                }
            }

            if (errno != Interop.Error.SUCCESS)
            {
                return -1;
            }

            socketAddressLen = sockAddrLen;
            return checked((int)received);
        }