pthread_setcanceltype.c 4.28 KB
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/*
 * pthread_setcanceltype.c
 *
 * Description:
 * POSIX thread functions related to thread cancellation.
 *
 * --------------------------------------------------------------------------
 *
 *      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 "pthread.h"
#include "implement.h"


int
pthread_setcanceltype (int type, int *oldtype)
/*
 * ------------------------------------------------------
 * DOCPUBLIC
 *      This function atomically sets the calling thread's
 *      cancelability type to 'type' and returns the previous
 *      cancelability type at the location referenced by
 *      'oldtype'
 *
 * PARAMETERS
 *      type,
 *      oldtype
 *              PTHREAD_CANCEL_DEFERRED
 *                      only deferred cancelation is allowed,
 *
 *              PTHREAD_CANCEL_ASYNCHRONOUS
 *                      Asynchronous cancellation is allowed
 *
 *
 * DESCRIPTION
 *      This function atomically sets the calling thread's
 *      cancelability type to 'type' and returns the previous
 *      cancelability type at the location referenced by
 *      'oldtype'
 *
 *      NOTES:
 *      1)      Use with caution; most code is not safe for use
 *              with asynchronous cancelability.
 *
 * COMPATIBILITY ADDITIONS
 *      If 'oldtype' is NULL then the previous type is not returned
 *      but the function still succeeds. (Solaris)
 *
 * RESULTS
 *              0               successfully set cancelability type,
 *              EINVAL          'type' is invalid
 *              EPERM           Async cancellation is not supported.
 *
 * ------------------------------------------------------
 */
{
  int result = 0;
  pthread_t self = pthread_self ();
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  pte_thread_t * sp = (pte_thread_t *) self;
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#ifndef PTE_SUPPORT_ASYNC_CANCEL
  if (type == PTHREAD_CANCEL_ASYNCHRONOUS)
    {
      /* Async cancellation is not supported at this time.  See notes in
       * pthread_cancel.
       */
      return EPERM;
    }
#endif /* PTE_SUPPORT_ASYNC_CANCEL */

  if (sp == NULL
      || (type != PTHREAD_CANCEL_DEFERRED
          && type != PTHREAD_CANCEL_ASYNCHRONOUS))
    {
      return EINVAL;
    }

  /*
   * Lock for async-cancel safety.
   */
  (void) pthread_mutex_lock (&sp->cancelLock);

  if (oldtype != NULL)
    {
      *oldtype = sp->cancelType;
    }

  sp->cancelType = type;

  /*
   * Check if there is a pending asynchronous cancel
   */

  if (sp->cancelState == PTHREAD_CANCEL_ENABLE
      && (type == PTHREAD_CANCEL_ASYNCHRONOUS)
      && (pte_osThreadCheckCancel(sp->threadId) == PTE_OS_INTERRUPTED) )
    {
      sp->state = PThreadStateCanceling;
      sp->cancelState = PTHREAD_CANCEL_DISABLE;
      (void) pthread_mutex_unlock (&sp->cancelLock);
      pte_throw (PTE_EPS_CANCEL);

      /* Never reached */
    }

  (void) pthread_mutex_unlock (&sp->cancelLock);

  return (result);

}				/* pthread_setcanceltype */