native_client_sdk/src/libraries/third_party/pthreads-win32/pthread_spin_init.c

   1 /*
   2  * pthread_spin_init.c
   3  *
   4  * Description:
   5  * This translation unit implements spin lock primitives.
   6  *
   7  * --------------------------------------------------------------------------
   8  *
   9  *      Pthreads-win32 - POSIX Threads Library for Win32
  10  *      Copyright(C) 1998 John E. Bossom
  11  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  12  *
  13  *      Contact Email: rpj@callisto.canberra.edu.au
  14  *
  15  *      The current list of contributors is contained
  16  *      in the file CONTRIBUTORS included with the source
  17  *      code distribution. The list can also be seen at the
  18  *      following World Wide Web location:
  19  *      http://sources.redhat.com/pthreads-win32/contributors.html
  20  *
  21  *      This library is free software; you can redistribute it and/or
  22  *      modify it under the terms of the GNU Lesser General Public
  23  *      License as published by the Free Software Foundation; either
  24  *      version 2 of the License, or (at your option) any later version.
  25  *
  26  *      This library is distributed in the hope that it will be useful,
  27  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  29  *      Lesser General Public License for more details.
  30  *
  31  *      You should have received a copy of the GNU Lesser General Public
  32  *      License along with this library in the file COPYING.LIB;
  33  *      if not, write to the Free Software Foundation, Inc.,
  34  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  35  */
  36
  37 #include "pthread.h"
  38 #include "implement.h"
  39
  40
  41 int
  42 pthread_spin_init (pthread_spinlock_t * lock, int pshared)
  43 {
  44   pthread_spinlock_t s;
  45   int cpus = 0;
  46   int result = 0;
  47
  48   if (lock == NULL)
  49     {
  50       return EINVAL;
  51     }
  52
  53   if (0 != ptw32_getprocessors (&cpus))
  54     {
  55       cpus = 1;
  56     }
  57
  58   if (cpus > 1)
  59     {
  60       if (pshared == PTHREAD_PROCESS_SHARED)
  61         {
  62           /*
  63            * Creating spinlock that can be shared between
  64            * processes.
  65            */
  66 #if _POSIX_THREAD_PROCESS_SHARED >= 0
  67
  68           /*
  69            * Not implemented yet.
  70            */
  71
  72 #error ERROR [__FILE__, line __LINE__]: Process shared spin locks are not supported yet.
  73
  74 #else
  75
  76           return ENOSYS;
  77
  78 #endif /* _POSIX_THREAD_PROCESS_SHARED */
  79
  80         }
  81     }
  82
  83   s = (pthread_spinlock_t) calloc (1, sizeof (*s));
  84
  85   if (s == NULL)
  86     {
  87       return ENOMEM;
  88     }
  89
  90   if (cpus > 1)
  91     {
  92       s->u.cpus = cpus;
  93       s->interlock = PTW32_SPIN_UNLOCKED;
  94     }
  95   else
  96     {
  97       pthread_mutexattr_t ma;
  98       result = pthread_mutexattr_init (&ma);
  99
 100       if (0 == result)
 101         {
 102           ma->pshared = pshared;
 103           result = pthread_mutex_init (&(s->u.mutex), &ma);
 104           if (0 == result)
 105             {
 106               s->interlock = PTW32_SPIN_USE_MUTEX;
 107             }
 108         }
 109       (void) pthread_mutexattr_destroy (&ma);
 110     }
 111
 112   if (0 == result)
 113     {
 114       *lock = s;
 115     }
 116   else
 117     {
 118       (void) free (s);
 119       *lock = NULL;
 120     }
 121
 122   return (result);
 123 }