1/* pthread_barrier_wait. Generic version.
2 Copyright (C) 2002-2022 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#include <pthread.h>
20#include <assert.h>
21
22#include <pt-internal.h>
23
24int
25pthread_barrier_wait (pthread_barrier_t *barrier)
26{
27 __pthread_spin_wait (&barrier->__lock);
28 if (--barrier->__pending == 0)
29 {
30 barrier->__pending = barrier->__count;
31
32 if (barrier->__count == 1)
33 __pthread_spin_unlock (&barrier->__lock);
34 else
35 {
36 struct __pthread *wakeup;
37 unsigned n = 0;
38
39 __pthread_queue_iterate (barrier->__queue, wakeup)
40 n++;
41
42 {
43 struct __pthread *wakeups[n];
44 unsigned i = 0;
45
46 __pthread_dequeuing_iterate (barrier->__queue, wakeup)
47 wakeups[i++] = wakeup;
48
49 barrier->__queue = NULL;
50 __pthread_spin_unlock (&barrier->__lock);
51
52 for (i = 0; i < n; i++)
53 __pthread_wakeup (wakeups[i]);
54 }
55 }
56
57 return PTHREAD_BARRIER_SERIAL_THREAD;
58 }
59 else
60 {
61 struct __pthread *self = _pthread_self ();
62
63 /* Add ourselves to the list of waiters. */
64 __pthread_enqueue (&barrier->__queue, self);
65 __pthread_spin_unlock (&barrier->__lock);
66
67 __pthread_block (self);
68 return 0;
69 }
70}
71

source code of glibc/sysdeps/htl/pt-barrier-wait.c