Question

我尝试使用C＃创建管道。代码很简单，但是我收到一条错误，说“尝试读取或写入受保护的内存。这通常表明其他内存已损坏。”

这是我表格的完整代码：

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 !");
    }   
}

在顶部我声明：使用DWORD = System.UInt32;

非常感谢有人可以提供帮助。

Answer 1

受保护内存违规的原因是因为CreatePipe的Windows API期望指针值到内存区域，该函数将用作安全属性结构的弹簧板。只需传入SECURITY_ATTRIBUTES结构就会覆盖安全内存（尚未分配给应用程序的页面），从而导致受保护的内存错误。

传入IntPtr来表示此指针，解决了您的问题。

    [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

只需更改声明，以便SECURITY_ATTRIBUTES为指针：

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

C＃CreatePipe（） - ＆gt;受保护的内存错误

2 个答案: