nptl/pthread_barrier_init.c

   1 /* Copyright (C) 2002-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include "pthreadP.h"
  21 #include <futex-internal.h>
  22 #include <kernel-features.h>
  23
  24
  25 static const struct pthread_barrierattr default_barrierattr =
  26   {
  27     .pshared = PTHREAD_PROCESS_PRIVATE
  28   };
  29
  30
  31 int
  32 __pthread_barrier_init (pthread_barrier_t *barrier,
  33                         const pthread_barrierattr_t *attr, unsigned int count)
  34 {
  35   struct pthread_barrier *ibarrier;
  36
  37   /* XXX EINVAL is not specified by POSIX as a possible error code for COUNT
  38      being too large.  See pthread_barrier_wait for the reason for the
  39      comparison with BARRIER_IN_THRESHOLD.  */
  40   if (__glibc_unlikely (count == 0 || count >= BARRIER_IN_THRESHOLD))
  41     return EINVAL;
  42
  43   const struct pthread_barrierattr *iattr
  44     = (attr != NULL
  45        ? (struct pthread_barrierattr *) attr
  46        : &default_barrierattr);
  47
  48   ibarrier = (struct pthread_barrier *) barrier;
  49
  50   /* Initialize the individual fields.  */
  51   ibarrier->in = 0;
  52   ibarrier->out = 0;
  53   ibarrier->count = count;
  54   ibarrier->current_round = 0;
  55   ibarrier->shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE
  56                       ? FUTEX_PRIVATE : FUTEX_SHARED);
  57
  58   return 0;
  59 }
  60 weak_alias (__pthread_barrier_init, pthread_barrier_init)