e i g h t - c u b e d . c o m 

/* Copyright 2003-2023 James F. Duff */
/* License and disclaimer: http://www.eight-cubed.com/disclaimer.html */

#define __NEW_STARLET 1

#include <stdio.h>
#include <stdlib.h>
#include <ssdef.h>
#include <stsdef.h>
#include <syidef.h>
#include <iosbdef.h>
#include <iledef.h>
#include <efndef.h>
#include <capdef.h>
#include <gen64def.h>
#include <lib$routines.h>
#include <starlet.h>

#include "errchk.h"


/******************************************************************************/
int main (void) {
/*
** You need ALTPRI to run this code.
*/

#ifdef VAX
#  error "Alpha/IPF specific code"
#endif /* VAX */

static IOSB iosb;

static GENERIC_64 state;
static GENERIC_64 cpu_mask;
static GENERIC_64 prev_mask;

static int r0_status;
static unsigned int active_cpus;

static int cpu_id;

static ILE3 syiitms[] = { 4, SYI$_ACTIVE_CPU_MASK, &active_cpus, NULL,
                          0, 0, NULL, NULL };

    r0_status = sys$getsyiw (EFN$C_ENF,
                             0,
                             0,
                             syiitms,
                             &iosb,
                             0,
                             0);
    errchk_sig (r0_status);
    errchk_sig (iosb.iosb$l_getxxi_status);

    /*
    ** Find the first active CPU in the set.
    */
    for (cpu_id = 0; cpu_id < sizeof (active_cpus) * 8 - 1; cpu_id++) {
        if ((active_cpus & (1<<cpu_id)) != 0) {
            break;
        }
    }

    state.gen64$q_quadword = CAP$K_ALL_CPU_ADD;
    cpu_mask.gen64$q_quadword = 1<<cpu_id;
    r0_status = sys$process_affinity (0,
                                      0,
                                      &cpu_mask,
                                      &state,
                                      &prev_mask,
                                      0);
    if (r0_status == SS$_NOPRIV) {
        (void)fprintf (stderr, "You need ALTPRI privilege to run this code\n");
        exit (EXIT_FAILURE);
    } else {
        errchk_sig (r0_status);
        (void)printf ("This thread's affinity set to CPU %u\n", cpu_id);
    }

    state.gen64$q_quadword = CAP$K_ALL_CPU_REMOVE;
    cpu_mask.gen64$q_quadword = 1<<cpu_id;
    r0_status = sys$process_affinity (0,
                                      0,
                                      &cpu_mask,
                                      &state,
                                      &prev_mask,
                                      0);
    errchk_sig (r0_status);
    (void)printf ("Cleared this thread's affinity\n");
}