C # CreatePipe () & # 8594; Protected Memory Error

Question

I am trying to create a channel using C #. The code is pretty simple, but I get the error message "Attempting to read or write protected memory. This often indicates that the other memory is damaged."

Here's the COMPLETE code of my form:

public partial class Form1 : Form
{
    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    public static extern bool CreatePipe(out SafeFileHandle hReadPipe, out SafeFileHandle hWritePipe, SECURITY_ATTRIBUTES lpPipeAttributes, int nSize);

    [StructLayout(LayoutKind.Sequential)]
    public struct SECURITY_ATTRIBUTES
    {
        public DWORD nLength;
        public IntPtr lpSecurityDescriptor;
        public bool bInheritHandle;
    }

    public Form1()
    {
        InitializeComponent();
    }

    private void btCreate_Click(object sender, EventArgs e)
    {
        SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES();
        sa.nLength = (DWORD)System.Runtime.InteropServices.Marshal.SizeOf(sa);
        sa.lpSecurityDescriptor = IntPtr.Zero;
        sa.bInheritHandle = true;

        SafeFileHandle hWrite = null;
        SafeFileHandle hRead = null;

        if (CreatePipe(out hRead, out hWrite, sa, 4096))
        {
            MessageBox.Show("Pipe created !");
        }
        else
            MessageBox.Show("Error : Pipe not created !");
    }   
}

At the top, I declare: using DWORD = System.UInt32;

Thanks so much if anyone can help.

Answer 1

, Windows API CreatePipe , spring . SECURITY_ATTRIBUTES (, ) , , .

IntPtr .

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    public static extern bool CreatePipe(ref IntPtr hReadPipe, ref IntPtr hWritePipe, IntPtr  lpPipeAttributes, int nSize);

    [StructLayout(LayoutKind.Sequential)]
    public struct SECURITY_ATTRIBUTES
    {
        public DWORD nLength;
        public IntPtr lpSecurityDescriptor;
        [MarshalAs(UnmanagedType.Bool)]
        public bool bInheritHandle;
    }

    public Form1()
    {
        InitializeComponent();
    }

    private void btnCreate_Click(object sender, EventArgs e)
    {

        SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES();
        sa.nLength = (DWORD)System.Runtime.InteropServices.Marshal.SizeOf(sa);
        sa.lpSecurityDescriptor = IntPtr.Zero;
        sa.bInheritHandle = true;

        IntPtr attr = Marshal.AllocHGlobal(Marshal.SizeOf(sa));
        Marshal.StructureToPtr(sa, attr, true);

        IntPtr hWrite = new IntPtr();
        IntPtr hRead = new IntPtr();

        if (CreatePipe(ref hRead, ref hWrite, attr, 4096))
        {
            MessageBox.Show("Pipe created !");
        }
        else
        {
            int error = Marshal.GetLastWin32Error();
            MessageBox.Show("Error : Pipe not created ! LastError= " + error);
        }
    }

Answer 2

, SECURITY_ATTRIBUTES :

public static extern bool CreatePipe(out SafeFileHandle hReadPipe, out SafeFileHandle hWritePipe, ref SECURITY_ATTRIBUTES lpPipeAttributes, int nSize);