1  /* Test barriers.
       2     Copyright (C) 2000-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library;  if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #define _GNU_SOURCE
      20  
      21  #include <pthread.h>
      22  #include <stdio.h>
      23  #include <error.h>
      24  #include <assert.h>
      25  #include <errno.h>
      26  
      27  #define THREADS 500
      28  #define WAITS 3
      29  
      30  void *
      31  dowait (void *arg)
      32  {
      33    pthread_barrier_t *barrier = arg;
      34    int ret;
      35  
      36    ret = pthread_barrier_wait (barrier);
      37    printf ("%d ", pthread_self ());
      38    return (void *) ret;
      39  }
      40  
      41  int
      42  main (int argc, char **argv)
      43  {
      44    pthread_barrierattr_t attr;
      45    pthread_barrier_t barrier;
      46  
      47    int i, j;
      48    error_t err;
      49    pthread_t tid[THREADS];
      50  
      51    int havesyncs;
      52  
      53    err = pthread_barrierattr_init (&attr);
      54    if (err)
      55      error (1, err, "pthread_barrierattr_init");
      56  
      57    err = pthread_barrierattr_getpshared (&attr, &i);
      58    if (err)
      59      error (1, err, "pthread_barrierattr_getpshared");
      60    assert (i == PTHREAD_PROCESS_PRIVATE || i == PTHREAD_PROCESS_SHARED);
      61  
      62    err = pthread_barrierattr_setpshared (&attr, PTHREAD_PROCESS_PRIVATE);
      63    if (err)
      64      error (1, err, "pthread_barrierattr_setpshared");
      65  
      66    err = pthread_barrier_init (&barrier, &attr, THREADS + 1);
      67    if (err)
      68      error (1, err, "pthread_barrier_init");
      69  
      70    for (j = 0; j < WAITS; j++)
      71      {
      72  
      73        for (i = 0; i < THREADS; i++)
      74  	{
      75  	  err = pthread_create (&tid[i], 0, dowait, &barrier);
      76  	  if (err)
      77  	    error (1, err, "pthread_create (%d)", i);
      78  	}
      79  
      80        printf ("Manager will now call pthread_barrier_wait.\n");
      81  
      82        havesyncs
      83  	  = pthread_barrier_wait (&barrier) == PTHREAD_BARRIER_SERIAL_THREAD
      84  	  ? 1 : 0;
      85  
      86        for (i = THREADS - 1; i >= 0; i--)
      87  	{
      88  	  void *ret;
      89  	  err = pthread_join (tid[i], &ret);
      90  	  if (err)
      91  	    error (1, err, "pthread_join");
      92  
      93  	  switch ((int) ret)
      94  	    {
      95  	    case 0:
      96  	      break;
      97  
      98  	    case PTHREAD_BARRIER_SERIAL_THREAD:
      99  	      havesyncs++;
     100  	      break;
     101  
     102  	    default:
     103  	      assert (!"Unknown value returned from pthread_barrier_wait.");
     104  	      break;
     105  	    }
     106  	}
     107  
     108        printf ("\n");
     109  
     110        assert (havesyncs == 1);
     111      }
     112  
     113    return 0;
     114  }