To set the affinity of CPUs using C#

Question

I have created a window application in C#.Now I want to set the CPU affinity for this application.I may have 2 processors,4 processors,8 processors or may be more than 8 process

Answer 1

For people looking for thread affinity.

public class CpuAffinity
{
    [DllImport("kernel32.dll")]
    static extern IntPtr GetCurrentThread();

    [DllImport("kernel32.dll")]
    static extern IntPtr SetThreadAffinityMask(IntPtr hThread, IntPtr dwThreadAffinityMask);

    /// 

    /// Sets the current Thread to have affinity to the specified cpu/processor if the system has more than one.
    /// 
    /// Supports most systems as we use a signed int; Anything more than 31 CPU's will not be supported.
    /// 
    /// The index of CPU to set.
    public static void SetCurrentThreadToHaveCpuAffinityFor(int cpu)
    {
        if (cpu < 0)
        {
            throw new ArgumentOutOfRangeException("cpu");
        }

        if (Environment.ProcessorCount > 1)
        {
            var ptr = GetCurrentThread();
            SetThreadAffinityMask(ptr, new IntPtr(1 << cpu));

            Debug.WriteLine("Current Thread Of OS Id '{0}' Affinity Set for CPU #{1}.", ptr, cpu);
        }else
        {
            Debug.WriteLine("The System only has one Processor.  It is impossible to set CPU affinity for other CPU's that do not exist.");
        }
    }
}