Listing 8-1 extracted from chapter Interoperability between .NET and native code/COM/ COM+

Listing 7-21<     > Listing 8-2

This listing can be compiled with the command line:
csc.exe /target:exe Example_8_1.cs
Errors: 0 Warnings: 0

using System.Runtime.InteropServices;
class Program {
   [DllImport("Kernel32.dll")]
   public static extern bool Beep( uint iFreq, uint iDuration );
   static void Main() {
      bool b = Beep(100, 100);
   }
}