如何使用Mono在Linux中P/Invoke getaddrinfo

[DllImport("libc")]
private static extern int getaddrinfo(string nodename, string servname, ref IntPtr hints, out IntPtr res);

[DllImport("libc")]
private static extern void freeaddrinfo(IntPtr res);

[StructLayout(LayoutKind.Sequential)]
private struct addrinfo
{
    public int ai_flags;
    public int ai_family;
    public int ai_socktype;
    public int ai_protocol;
    public IntPtr ai_canonname;
    public IntPtr ai_addr;
    public IntPtr ai_next;
}

IntPtr hints = IntPtr.Zero;
IntPtr res = IntPtr.Zero;

try
{
    hints = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(addrinfo)));
    res = IntPtr.Zero;

    // 设置hints参数
    // ...

    // 调用getaddrinfo函数
    int result = getaddrinfo("example.com", null, ref hints, out res);
    if (result != 0)
    {
        // 错误处理
        // ...
    }

    // 处理返回的addrinfo结构体
    // ...
}
finally
{
    // 释放资源
    if (res != IntPtr.Zero)
    {
        freeaddrinfo(res);
    }

    if (hints != IntPtr.Zero)
    {
        Marshal.FreeHGlobal(hints);
    }
}