nptl/pthread_barrier_init.c

   1 /* Copyright (C) 2002, 2007 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include "pthreadP.h"
  22 #include <lowlevellock.h>
  23 #include <kernel-features.h>
  24
  25
  26 static const struct pthread_barrierattr default_attr =
  27   {
  28     .pshared = PTHREAD_PROCESS_PRIVATE
  29   };
  30
  31
  32 int
  33 pthread_barrier_init (barrier, attr, count)
  34      pthread_barrier_t *barrier;
  35      const pthread_barrierattr_t *attr;
  36      unsigned int count;
  37 {
  38   struct pthread_barrier *ibarrier;
  39
  40   if (__builtin_expect (count == 0, 0))
  41     return EINVAL;
  42
  43   const struct pthread_barrierattr *iattr
  44     = (attr != NULL
  45        ? iattr = (struct pthread_barrierattr *) attr
  46        : &default_attr);
  47
  48   if (iattr->pshared != PTHREAD_PROCESS_PRIVATE
  49       && __builtin_expect (iattr->pshared != PTHREAD_PROCESS_SHARED, 0))
  50     /* Invalid attribute.  */
  51     return EINVAL;
  52
  53   ibarrier = (struct pthread_barrier *) barrier;
  54
  55   /* Initialize the individual fields.  */
  56   ibarrier->lock = LLL_LOCK_INITIALIZER;
  57   ibarrier->left = count;
  58   ibarrier->init_count = count;
  59   ibarrier->curr_event = 0;
  60
  61 #ifdef __ASSUME_PRIVATE_FUTEX
  62   ibarrier->private = (iattr->pshared != PTHREAD_PROCESS_PRIVATE
  63                        ? 0 : FUTEX_PRIVATE_FLAG);
  64 #else
  65   ibarrier->private = (iattr->pshared != PTHREAD_PROCESS_PRIVATE
  66                        ? 0 : THREAD_GETMEM (THREAD_SELF,
  67                                             header.private_futex));
  68 #endif
  69
  70   return 0;
  71 }