SetThreadAffinityMask无效

Question

I want a test program only run on cpu1 ,so i write the code like that

#include <iostream>
#include <windows.h>

    int main(){
        ::SetThreadAffinityMask(::GetCurrentProcess(),1);
        while(1)
          ;
       return 0;
    }

but when I open the task manager, I find CPU1 is not full used, and the percent of it's usage is always changing.Why?CPU1 should be 100 percent usage? sorry to my english.

Answer 1

SetThreadAffinityMask sets the affinity of a THREAD not of the whole process. If you check the return value you should see that SetThreadAffinityMask is failing. To get the current thread use GetCurrentThread() not GetCurrentProcess() .

ie change your code to

SetThreadAffinityMask(GetCurrentThread(),1) 

If you want to set the affinity of the whole process use

SetProcessAffinityMask(GetCurrentProcess(),1)