#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h> // for the exit function
#include <pthread.h>
#include <errno.h>
/* In the following program, the main thread uses pthread_setaffinity_np() to set its CPU
affinity mask to include CPUs 0 to 7 (which may not all be available on the system), and
then calls pthread_getaffinity_np() to check the resulting CPU affinity mask of the
thread. */
#define handle_error_en(en, msg) \
do { errno=en; perror(msg); exit(EXIT_FAILURE);} while(0) // perror prints the error
message
//
mark the way the macro has used the do while wrapper
int main(int argc, char *argv[])
{
pthread_t t = pthread_self();
cpu_set_t cpuset;
CPU_ZERO(&cpuset); // clears set so that it contains no CPUs
int j;
for(j=0;j<8;j++) // setting affinity mask to include CPUs 0-7
CPU_SET(j, &cpuset);
int rt = pthread_setaffinity_np(t, sizeof(cpu_set_t), &cpuset);
if(rt!=0)
handle_error_en(rt, "pthread_setaffinity_np");
rt = pthread_getaffinity_np(t, sizeof(cpu_set_t), &cpuset); // checking the actual
affinity mask
printf("Set returned by pthread_getaffinity_np contained: \n");
for(j=0; j<CPU_SETSIZE; j++)
if(CPU_ISSET(j, &cpuset))
printf("CPU%d\n", j);
return 0;
}
