1*062c5bc4SJason Schmidlapp /*
2*062c5bc4SJason Schmidlapp * pthread_barrier_init.c
3*062c5bc4SJason Schmidlapp *
4*062c5bc4SJason Schmidlapp * Description:
5*062c5bc4SJason Schmidlapp * This translation unit implements barrier primitives.
6*062c5bc4SJason Schmidlapp *
7*062c5bc4SJason Schmidlapp * --------------------------------------------------------------------------
8*062c5bc4SJason Schmidlapp *
9*062c5bc4SJason Schmidlapp * Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
10*062c5bc4SJason Schmidlapp * Copyright(C) 2008 Jason Schmidlapp
11*062c5bc4SJason Schmidlapp *
12*062c5bc4SJason Schmidlapp * Contact Email: jschmidlapp@users.sourceforge.net
13*062c5bc4SJason Schmidlapp *
14*062c5bc4SJason Schmidlapp *
15*062c5bc4SJason Schmidlapp * Based upon Pthreads-win32 - POSIX Threads Library for Win32
16*062c5bc4SJason Schmidlapp * Copyright(C) 1998 John E. Bossom
17*062c5bc4SJason Schmidlapp * Copyright(C) 1999,2005 Pthreads-win32 contributors
18*062c5bc4SJason Schmidlapp *
19*062c5bc4SJason Schmidlapp * Contact Email: rpj@callisto.canberra.edu.au
20*062c5bc4SJason Schmidlapp *
21*062c5bc4SJason Schmidlapp * The original list of contributors to the Pthreads-win32 project
22*062c5bc4SJason Schmidlapp * is contained in the file CONTRIBUTORS.ptw32 included with the
23*062c5bc4SJason Schmidlapp * source code distribution. The list can also be seen at the
24*062c5bc4SJason Schmidlapp * following World Wide Web location:
25*062c5bc4SJason Schmidlapp * http://sources.redhat.com/pthreads-win32/contributors.html
26*062c5bc4SJason Schmidlapp *
27*062c5bc4SJason Schmidlapp * This library is free software; you can redistribute it and/or
28*062c5bc4SJason Schmidlapp * modify it under the terms of the GNU Lesser General Public
29*062c5bc4SJason Schmidlapp * License as published by the Free Software Foundation; either
30*062c5bc4SJason Schmidlapp * version 2 of the License, or (at your option) any later version.
31*062c5bc4SJason Schmidlapp *
32*062c5bc4SJason Schmidlapp * This library is distributed in the hope that it will be useful,
33*062c5bc4SJason Schmidlapp * but WITHOUT ANY WARRANTY; without even the implied warranty of
34*062c5bc4SJason Schmidlapp * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
35*062c5bc4SJason Schmidlapp * Lesser General Public License for more details.
36*062c5bc4SJason Schmidlapp *
37*062c5bc4SJason Schmidlapp * You should have received a copy of the GNU Lesser General Public
38*062c5bc4SJason Schmidlapp * License along with this library in the file COPYING.LIB;
39*062c5bc4SJason Schmidlapp * if not, write to the Free Software Foundation, Inc.,
40*062c5bc4SJason Schmidlapp * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
41*062c5bc4SJason Schmidlapp */
42*062c5bc4SJason Schmidlapp
43*062c5bc4SJason Schmidlapp #include <stdlib.h>
44*062c5bc4SJason Schmidlapp
45*062c5bc4SJason Schmidlapp #include "pthread.h"
46*062c5bc4SJason Schmidlapp #include "implement.h"
47*062c5bc4SJason Schmidlapp
48*062c5bc4SJason Schmidlapp
49*062c5bc4SJason Schmidlapp int
pthread_barrier_init(pthread_barrier_t * barrier,const pthread_barrierattr_t * attr,unsigned int count)50*062c5bc4SJason Schmidlapp pthread_barrier_init (pthread_barrier_t * barrier,
51*062c5bc4SJason Schmidlapp const pthread_barrierattr_t * attr, unsigned int count)
52*062c5bc4SJason Schmidlapp {
53*062c5bc4SJason Schmidlapp pthread_barrier_t b;
54*062c5bc4SJason Schmidlapp
55*062c5bc4SJason Schmidlapp if (barrier == NULL || count == 0)
56*062c5bc4SJason Schmidlapp {
57*062c5bc4SJason Schmidlapp return EINVAL;
58*062c5bc4SJason Schmidlapp }
59*062c5bc4SJason Schmidlapp
60*062c5bc4SJason Schmidlapp if (NULL != (b = (pthread_barrier_t) calloc (1, sizeof (*b))))
61*062c5bc4SJason Schmidlapp {
62*062c5bc4SJason Schmidlapp b->pshared = (attr != NULL && *attr != NULL
63*062c5bc4SJason Schmidlapp ? (*attr)->pshared : PTHREAD_PROCESS_PRIVATE);
64*062c5bc4SJason Schmidlapp
65*062c5bc4SJason Schmidlapp b->nCurrentBarrierHeight = b->nInitialBarrierHeight = count;
66*062c5bc4SJason Schmidlapp b->iStep = 0;
67*062c5bc4SJason Schmidlapp
68*062c5bc4SJason Schmidlapp /*
69*062c5bc4SJason Schmidlapp * Two semaphores are used in the same way as two stepping
70*062c5bc4SJason Schmidlapp * stones might be used in crossing a stream. Once all
71*062c5bc4SJason Schmidlapp * threads are safely on one stone, the other stone can
72*062c5bc4SJason Schmidlapp * be moved ahead, and the threads can start moving to it.
73*062c5bc4SJason Schmidlapp * If some threads decide to eat their lunch before moving
74*062c5bc4SJason Schmidlapp * then the other threads have to wait.
75*062c5bc4SJason Schmidlapp */
76*062c5bc4SJason Schmidlapp if (0 == sem_init (&(b->semBarrierBreeched[0]), b->pshared, 0))
77*062c5bc4SJason Schmidlapp {
78*062c5bc4SJason Schmidlapp if (0 == sem_init (&(b->semBarrierBreeched[1]), b->pshared, 0))
79*062c5bc4SJason Schmidlapp {
80*062c5bc4SJason Schmidlapp *barrier = b;
81*062c5bc4SJason Schmidlapp return 0;
82*062c5bc4SJason Schmidlapp }
83*062c5bc4SJason Schmidlapp (void) sem_destroy (&(b->semBarrierBreeched[0]));
84*062c5bc4SJason Schmidlapp }
85*062c5bc4SJason Schmidlapp (void) free (b);
86*062c5bc4SJason Schmidlapp }
87*062c5bc4SJason Schmidlapp
88*062c5bc4SJason Schmidlapp return ENOMEM;
89*062c5bc4SJason Schmidlapp }
90