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

   1 /*
   2  * pthread_key_delete.c
   3  *
   4  * Description:
   5  * POSIX thread functions which implement thread-specific data (TSD).
   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_key_delete (pthread_key_t key)
  43      /*
  44       * ------------------------------------------------------
  45       * DOCPUBLIC
  46       *      This function deletes a thread-specific data key. This
  47       *      does not change the value of the thread specific data key
  48       *      for any thread and does not run the key's destructor
  49       *      in any thread so it should be used with caution.
  50       *
  51       * PARAMETERS
  52       *      key
  53       *              pointer to an instance of pthread_key_t
  54       *
  55       *
  56       * DESCRIPTION
  57       *      This function deletes a thread-specific data key. This
  58       *      does not change the value of the thread specific data key
  59       *      for any thread and does not run the key's destructor
  60       *      in any thread so it should be used with caution.
  61       *
  62       * RESULTS
  63       *              0               successfully deleted the key,
  64       *              EINVAL          key is invalid,
  65       *
  66       * ------------------------------------------------------
  67       */
  68 {
  69   ptw32_mcs_local_node_t keyLock;
  70   int result = 0;
  71
  72   if (key != NULL)
  73     {
  74       if (key->threads != NULL && key->destructor != NULL)
  75         {
  76           ThreadKeyAssoc *assoc;
  77           ptw32_mcs_lock_acquire (&(key->keyLock), &keyLock);
  78           /*
  79            * Run through all Thread<-->Key associations
  80            * for this key.
  81            *
  82            * While we hold at least one of the locks guarding
  83            * the assoc, we know that the assoc pointed to by
  84            * key->threads is valid.
  85            */
  86           while ((assoc = (ThreadKeyAssoc *) key->threads) != NULL)
  87             {
  88               ptw32_mcs_local_node_t threadLock;
  89               ptw32_thread_t * thread = assoc->thread;
  90
  91               if (assoc == NULL)
  92                 {
  93                   /* Finished */
  94                   break;
  95                 }
  96
  97               ptw32_mcs_lock_acquire (&(thread->threadLock), &threadLock);
  98               /*
  99                * Since we are starting at the head of the key's threads
 100                * chain, this will also point key->threads at the next assoc.
 101                * While we hold key->keyLock, no other thread can insert
 102                * a new assoc via pthread_setspecific.
 103                */
 104               ptw32_tkAssocDestroy (assoc);
 105               ptw32_mcs_lock_release (&threadLock);
 106               ptw32_mcs_lock_release (&keyLock);
 107             }
 108         }
 109
 110       TlsFree (key->key);
 111       if (key->destructor != NULL)
 112         {
 113           /* A thread could be holding the keyLock */
 114           ptw32_mcs_lock_acquire (&(key->keyLock), &keyLock);
 115           ptw32_mcs_lock_release (&keyLock);
 116         }
 117
 118 #if defined( _DEBUG )
 119       memset ((char *) key, 0, sizeof (*key));
 120 #endif
 121       free (key);
 122     }
 123
 124   return (result);
 125 }