Imports System
Imports System.Text
Imports System.Runtime.InteropServices
Imports System.Security.Permissions



Public Structure Point
    Public x, y As Int32
End Structure



Public NotInheritable Class App

    <SecurityPermission(SecurityAction.LinkDemand, Unrestricted:=True)> _
    Shared Sub Main()
        ' Demonstrate the use of public static fields of the Marshal class.
        Console.WriteLine("SystemDefaultCharSize={0}, SystemMaxDBCSCharSize={1}", Marshal.SystemDefaultCharSize, Marshal.SystemMaxDBCSCharSize)
        ' Demonstrate the use of the SizeOf method of the Marshal class.
        Console.WriteLine("Number of bytes needed by a Point object: {0}", Marshal.SizeOf(GetType(Point)))
        Dim p As New Point()
        Console.WriteLine("Number of bytes needed by a Point object: {0}", Marshal.SizeOf(p))
        ' Demonstrate how to call GlobalAlloc and 
        ' GlobalFree using the Marshal class.
        Dim hglobal As IntPtr = Marshal.AllocHGlobal(100)
        Marshal.FreeHGlobal(hglobal)
        ' Demonstrate how to use the Marshal class to get the Win32 error 
        ' code when a Win32 method fails.
        Dim f As [Boolean] = CloseHandle(New IntPtr(-1))
        If Not f Then
            Console.WriteLine("CloseHandle call failed with an error code of: {0}", Marshal.GetLastWin32Error())
        End If

    End Sub


    ' This is a platform invoke prototype. SetLastError is true, which allows 
    ' the GetLastWin32Error method of the Marshal class to work correctly.    
    <DllImport("Kernel32", ExactSpelling:=True, SetLastError:=True)> _
    Shared Function CloseHandle(ByVal h As IntPtr) As [Boolean]

    End Function
End Class


' This code produces the following output.
' 
' SystemDefaultCharSize=2, SystemMaxDBCSCharSize=1
' Number of bytes needed by a Point object: 8
' Number of bytes needed by a Point object: 8
' CloseHandle call failed with an error code of: 6

using System;
using System.Text;
using System.Runtime.InteropServices;

public struct Point
{
    public Int32 x, y;
}


public sealed class App
{
    static void Main()
    {
        // Demonstrate the use of public static fields of the Marshal class.
        Console.WriteLine("SystemDefaultCharSize={0}, SystemMaxDBCSCharSize={1}",
            Marshal.SystemDefaultCharSize, Marshal.SystemMaxDBCSCharSize);

        // Demonstrate the use of the SizeOf method of the Marshal class.
        Console.WriteLine("Number of bytes needed by a Point object: {0}", 
            Marshal.SizeOf(typeof(Point)));
        Point p = new Point();
        Console.WriteLine("Number of bytes needed by a Point object: {0}",
            Marshal.SizeOf(p));

        // Demonstrate how to call GlobalAlloc and 
        // GlobalFree using the Marshal class.
        IntPtr hglobal = Marshal.AllocHGlobal(100);
        Marshal.FreeHGlobal(hglobal);

        // Demonstrate how to use the Marshal class to get the Win32 error 
        // code when a Win32 method fails.
        Boolean f = CloseHandle(new IntPtr(-1));
        if (!f)
        {
            Console.WriteLine("CloseHandle call failed with an error code of: {0}", 
                Marshal.GetLastWin32Error());
        }  
    }

    // This is a platform invoke prototype. SetLastError is true, which allows 
    // the GetLastWin32Error method of the Marshal class to work correctly.    
    [DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
    static extern Boolean CloseHandle(IntPtr h);

}

// This code produces the following output.
// 
// SystemDefaultCharSize=2, SystemMaxDBCSCharSize=1
// Number of bytes needed by a Point object: 8
// Number of bytes needed by a Point object: 8
// CloseHandle call failed with an error code of: 6

using namespace System;
using namespace System::Runtime::InteropServices;

public value struct Point
{
public:
    property int X;
    property int Y;
};
extern bool CloseHandle(IntPtr h);

int main()
{
    // Demonstrate the use of public static fields of the Marshal
    // class.
    Console::WriteLine(
        "SystemDefaultCharSize={0},SystemMaxDBCSCharSize={1}",
        Marshal::SystemDefaultCharSize,
        Marshal::SystemMaxDBCSCharSize);

    // Demonstrate the use of the SizeOf method of the Marshal
    // class.
    Console::WriteLine("Number of bytes needed by a Point object: {0}",
        Marshal::SizeOf(Point::typeid));
    Point point;
    Console::WriteLine("Number of bytes needed by a Point object: {0}",
        Marshal::SizeOf(point));

    // Demonstrate how to call GlobalAlloc and 
    // GlobalFree using the Marshal class.
    IntPtr hglobal = Marshal::AllocHGlobal(100);
    Marshal::FreeHGlobal(hglobal);

    // Demonstrate how to use the Marshal class to get the Win32
    // error code when a Win32 method fails.
    bool isCloseHandleSuccess = CloseHandle(IntPtr(-1));
    if (!isCloseHandleSuccess)
    {
        Console::WriteLine(
            "CloseHandle call failed with an error code of: {0}",
            Marshal::GetLastWin32Error());
    }
};

// This is a platform invoke prototype. SetLastError is true,
// which allows the GetLastWin32Error method of the Marshal class
// to work correctly.    
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
extern bool CloseHandle(IntPtr h);

// This code produces the following output.
// 
// SystemDefaultCharSize=2, SystemMaxDBCSCharSize=1
// Number of bytes needed by a Point object: 8
// Number of bytes needed by a Point object: 8
// CloseHandle call failed with an error code of: 6