relibc_pthreads-emb/pthread_key_create.c

/*
 * pthread_key_create.c
 *
 * Description:
 * POSIX thread functions which implement thread-specific data (TSD).
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
 *      Copyright(C) 2008 Jason Schmidlapp
 *
 *      Contact Email: jschmidlapp@users.sourceforge.net
 *
 *
 *      Based upon Pthreads-win32 - POSIX Threads Library for Win32
 *      Copyright(C) 1998 John E. Bossom
 *      Copyright(C) 1999,2005 Pthreads-win32 contributors
 *
 *      Contact Email: rpj@callisto.canberra.edu.au
 *
 *      The original list of contributors to the Pthreads-win32 project
 *      is contained in the file CONTRIBUTORS.ptw32 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
 */

#include <stdlib.h>

#include "pte_osal.h"

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


int
pthread_key_create (pthread_key_t * key, void (*destructor) (void *))
/*
 * ------------------------------------------------------
 * DOCPUBLIC
 *      This function creates a thread-specific data key visible
 *      to all threads. All existing and new threads have a value
 *      NULL for key until set using pthread_setspecific. When any
 *      thread with a non-NULL value for key terminates, 'destructor'
 *      is called with key's current value for that thread.
 *
 * PARAMETERS
 *      key
 *              pointer to an instance of pthread_key_t
 *
 *
 * DESCRIPTION
 *      This function creates a thread-specific data key visible
 *      to all threads. All existing and new threads have a value
 *      NULL for key until set using pthread_setspecific. When any
 *      thread with a non-NULL value for key terminates, 'destructor'
 *      is called with key's current value for that thread.
 *
 * RESULTS
 *              0               successfully created semaphore,
 *              EAGAIN          insufficient resources or PTHREAD_KEYS_MAX
 *                              exceeded,
 *              ENOMEM          insufficient memory to create the key,
 *
 * ------------------------------------------------------
 */
{
  int result = 0;
  pthread_key_t newkey;

  if ((newkey = (pthread_key_t) calloc (1, sizeof (*newkey))) == NULL)
    {
      result = ENOMEM;
    }
  else
    {
      pte_osResult osResult = pte_osTlsAlloc(&(newkey->key));

      if (osResult != PTE_OS_OK)
        {
          result = EAGAIN;

          free (newkey);
          newkey = NULL;
        }
      else if (destructor != NULL)
        {
          /*
           * Have to manage associations between thread and key;
           * Therefore, need a lock that allows multiple threads
           * to gain exclusive access to the key->threads list.
           *
           * The mutex will only be created when it is first locked.
           */
          newkey->keyLock = PTHREAD_MUTEX_INITIALIZER;
          newkey->destructor = destructor;
        }

    }

  *key = newkey;

  return (result);
}