text: /****************************************************************************
   * sched/pthread/pthread_keycreate.c
   *
   *   Copyright (C) 2007-2009, 2013 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <sched.h>
  #include <errno.h>
  #include <assert.h>
  #include <debug.h>
  
  #include "sched/sched.h"
  #include "pthread/pthread.h"
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  /****************************************************************************
   * Private Type Declarations
   ****************************************************************************/
  
  /****************************************************************************
   * Public Data
   ****************************************************************************/
  
  /****************************************************************************
   * Private Variables
   ****************************************************************************/
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: pthread_key_create
   *
   * Description:
   *   This function creates a thread-specific data key visible to all threads
   *   in the system.  Although the same key value may be used by different
   *   threads, the values bound to the key by pthread_setspecific() are
   *   maintained on a per-thread basis and persist for the life of the calling
   *   thread.
   *
   *   Upon key creation, the value NULL will be associated with the new key
   *   in all active threads.  Upon thread creation, the value NULL will be
   *   associated with all defined keys in the new thread.
   *
   * Parameters:
   *   key = A pointer to the key to create.
   *   destructor = An optional destructor() function that may be associated
   *      with each key that is invoked when a thread exits.  However, this
   *      argument is ignored in the current implementation.
   *
   * Return Value:
   *   If successful, the pthread_key_create() function will store the newly
   *   created key value at *key and return zero (OK).  Otherwise, an error
   *   number will bereturned to indicate the error:
   *
   *      EAGAIN - The system lacked sufficient resources to create another
   *         thread-specific data key, or the system-imposed limit on the total
   *         number of keys pers process {PTHREAD_KEYS_MAX} has been exceeded
   *      ENONMEM - Insufficient memory exists to create the key.
   *
   * Assumptions:
   *
   * POSIX Compatibility:
   *   - The present implementation ignores the destructor argument.
   *
   ****************************************************************************/
  
  int pthread_key_create(FAR pthread_key_t *key,
                         CODE void (*destructor)(FAR void *))
  {
  #if CONFIG_NPTHREAD_KEYS > 0
    FAR struct tcb_s *rtcb = this_task();
    FAR struct task_group_s *group = rtcb->group;
    int ret = EAGAIN;
  
    DEBUGASSERT(group);
  
    /* Check if we have exceeded the system-defined number of keys. */
  
    if (group->tg_nkeys < PTHREAD_KEYS_MAX)
      {
        /* Return the key value */
  
        *key = group->tg_nkeys;
  
        /* Increment the count of global keys. */
  
        group->tg_nkeys++;
  
        /* Return success. */
  
        ret = OK;
      }
  
    return ret;
  #else
    return ENOSYS;
  #endif
  }
  