nptl/pthread_barrier_init.c

   1 /* Copyright (C) 2002-2014 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 <lowlevellock.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 (barrier, attr, count)
  33      pthread_barrier_t *barrier;
  34      const pthread_barrierattr_t *attr;
  35      unsigned int count;
  36 {
  37   struct pthread_barrier *ibarrier;
  38
  39   if (__glibc_unlikely (count == 0))
  40     return EINVAL;
  41
  42   const struct pthread_barrierattr *iattr
  43     = (attr != NULL
  44        ? iattr = (struct pthread_barrierattr *) attr
  45        : &default_barrierattr);
  46
  47   if (iattr->pshared != PTHREAD_PROCESS_PRIVATE
  48       && __builtin_expect (iattr->pshared != PTHREAD_PROCESS_SHARED, 0))
  49     /* Invalid attribute.  */
  50     return EINVAL;
  51
  52   ibarrier = (struct pthread_barrier *) barrier;
  53
  54   /* Initialize the individual fields.  */
  55   ibarrier->lock = LLL_LOCK_INITIALIZER;
  56   ibarrier->left = count;
  57   ibarrier->init_count = count;
  58   ibarrier->curr_event = 0;
  59
  60 #ifdef __ASSUME_PRIVATE_FUTEX
  61   ibarrier->private = (iattr->pshared != PTHREAD_PROCESS_PRIVATE
  62                        ? 0 : FUTEX_PRIVATE_FLAG);
  63 #else
  64   ibarrier->private = (iattr->pshared != PTHREAD_PROCESS_PRIVATE
  65                        ? 0 : THREAD_GETMEM (THREAD_SELF,
  66                                             header.private_futex));
  67 #endif
  68
  69   return 0;
  70 }