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#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <error.h>
#include <errno.h>
#define THREADS 500
#define WAITS 3
void *
dowait (void *arg)
{
pthread_barrier_t *barrier = arg;
int ret;
ret = pthread_barrier_wait (barrier);
printf ("%d ", pthread_self ());
return (void *) ret;
}
int
main (int argc, char **argv)
{
pthread_barrierattr_t attr;
pthread_barrier_t barrier;
int i, j;
error_t err;
pthread_t tid[THREADS];
int havesyncs;
err = pthread_barrierattr_init (&attr);
if (err)
error (1, err, "pthread_barrierattr_init");
err = pthread_barrierattr_getpshared (&attr, &i);
if (err)
error (1, err, "pthread_barrierattr_getpshared");
assert (i == PTHREAD_PROCESS_PRIVATE || i == PTHREAD_PROCESS_SHARED);
err = pthread_barrierattr_setpshared (&attr, PTHREAD_PROCESS_PRIVATE);
if (err)
error (1, err, "pthread_barrierattr_setpshared");
err = pthread_barrier_init (&barrier, &attr, THREADS + 1);
if (err)
error (1, err, "pthread_barrier_init");
for (j = 0; j < WAITS; j ++)
{
for (i = 0; i < THREADS; i ++)
{
err = pthread_create (&tid[i], 0, dowait, &barrier);
if (err)
error (1, err, "pthread_create (%d)", i);
}
printf ("Manager will now call pthread_barrier_wait.\n");
havesyncs
= pthread_barrier_wait (&barrier) == PTHREAD_BARRIER_SERIAL_THREAD
? 1 : 0;
for (i = THREADS - 1; i >= 0; i --)
{
void *ret;
err = pthread_join (tid[i], &ret);
if (err)
error (1, err, "pthread_join");
switch ((int) ret)
{
case 0:
break;
case PTHREAD_BARRIER_SERIAL_THREAD:
havesyncs ++;
break;
default:
assert (! "Unknown value returned from pthread_barrier_wait.");
break;
}
}
printf ("\n");
assert (havesyncs == 1);
}
return 0;
}
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