Changing the affinity of a Console C# program

Question

In this page, the following code is an example for changing the affinity of the current process:

using System;
using System.Diagnostics;

class Program
{
    static void Main()
    {
        Process myProcess = Process.GetCurrentProcess();
        Console.WriteLine("ProcessorAffinity: {0}", myProcess.ProcessorAffinity);
        Process.GetCurrentProcess().ProcessorAffinity = (System.IntPtr)3;
        Console.WriteLine("ProcessorAffinity: {0} ", myProcess.ProcessorAffinity);
        Console.ReadKey();
    }
}

But the output for me is:

ProcessorAffinity: 255

ProcessorAffinity: 255

meaning that the affinity is not changed. What's the problem? And how can I change the affinity?

Answer 1

As @ChetanRanpariya mension in his comment, the issue is because you changeing ProcessorAffinity of one process object (returned from the second call of Process.GetCurrentProcess()) and checking it in another (returned from the first call of Process.GetCurrentProcess()). Here is corrected sample:

using (var currentProcess = Process.GetCurrentProcess())
{
    Console.WriteLine($"ProcessorAffinity: {currentProcess.ProcessorAffinity}");
    currentProcess.ProcessorAffinity = (System.IntPtr)3;
    Console.WriteLine($"ProcessorAffinity: {currentProcess.ProcessorAffinity}");
}