pthread_key_delete.c

/*
 * pthread_key_delete.c
 *
 * Description:
 * POSIX thread functions which implement thread-specific data (TSD).
 *
 * --------------------------------------------------------------------------
 *
 *      pthreads-win32 - POSIX Threads Library for Win32
 *      Copyright(C) 1998 John E. Bossom
 *      Copyright(C) 1999-2021 pthreads-win32 / pthreads4w contributors
 *
 *      Homepage1: http://sourceware.org/pthreads-win32/
 *      Homepage2: http://sourceforge.net/projects/pthreads4w/
 *
 *      The current list of contributors is contained
 *      in the file CONTRIBUTORS included with the source
 *      code distribution. The list can also be seen at the
 *      following World Wide Web location:
 *      http://sources.redhat.com/pthreads-win32/contributors.html
 * 
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation; either
 *      version 2 of the License, or (at your option) any later version.
 * 
 *      This library is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *      Lesser General Public License for more details.
 * 
 *      You should have received a copy of the GNU Lesser General Public
 *      License along with this library in the file COPYING.LIB;
 *      if not, write to the Free Software Foundation, Inc.,
 *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 *
 * --------------------------------------------------------------------------
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "pthread.h"
#include "implement.h"


int
pthread_key_delete (pthread_key_t key)
/*
 * ------------------------------------------------------
 * DOCPUBLIC
 *      This function deletes a thread-specific data key. This
 *      does not change the value of the thread specific data key
 *      for any thread and does not run the key's destructor
 *      in any thread so it should be used with caution.
 *
 * PARAMETERS
 *      key
 *              pointer to an instance of pthread_key_t
 *
 *
 * DESCRIPTION
 *      This function deletes a thread-specific data key. This
 *      does not change the value of the thread specific data key
 *      for any thread and does not run the key's destructor
 *      in any thread so it should be used with caution.
 *
 * RESULTS
 *              0               successfully deleted the key,
 *              EINVAL          key is invalid,
 *
 * ------------------------------------------------------
 */
{
  ptw32_mcs_local_node_t keyLock;
  int result = 0;

  if (key != NULL)
    {
      if (key->threads != NULL && key->destructor != NULL)
        {
          ThreadKeyAssoc *assoc;
          ptw32_mcs_lock_acquire (&(key->keyLock), &keyLock);
          /*
           * Run through all Thread<-->Key associations
           * for this key.
           *
           * While we hold at least one of the locks guarding
           * the assoc, we know that the assoc pointed to by
           * key->threads is valid.
           */
          while ((assoc = (ThreadKeyAssoc *) key->threads) != NULL)
            {
              ptw32_mcs_local_node_t threadLock;
              ptw32_thread_t * thread = assoc->thread;

              if (assoc == NULL)
                {
                  /* Finished */
                  break;
                }

              ptw32_mcs_lock_acquire (&(thread->threadLock), &threadLock);
              /*
               * Since we are starting at the head of the key's threads
               * chain, this will also point key->threads at the next assoc.
               * While we hold key->keyLock, no other thread can insert
               * a new assoc for this key via pthread_setspecific.
               */
              ptw32_tkAssocDestroy (assoc);
              ptw32_mcs_lock_release (&threadLock);
            }
          ptw32_mcs_lock_release (&keyLock);
        }

      TlsFree (key->key);
      if (key->destructor != NULL)
        {
          /* A thread could be holding the keyLock */
          ptw32_mcs_lock_acquire (&(key->keyLock), &keyLock);
          ptw32_mcs_lock_release (&keyLock);
        }

#if defined( _DEBUG )
      memset ((char *) key, 0, sizeof (*key));
#endif
      free (key);
    }

  return (result);
}