pthread_testcancel.c

/*
 * pthread_testcancel.c
 *
 * Description:
 * POSIX thread functions related to thread cancellation.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads4w - POSIX Threads for Windows
 *      Copyright 1998 John E. Bossom
 *      Copyright 1999-2018, Pthreads4w contributors
 *
 *      Homepage: https://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:
 *
 *      https://sourceforge.net/p/pthreads4w/wiki/Contributors/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

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


void
pthread_testcancel (void)
     /*
      * ------------------------------------------------------
      * DOCPUBLIC
      *      This function creates a deferred cancellation point
      *      in the calling thread. The call has no effect if the
      *      current cancelability state is
      *              PTHREAD_CANCEL_DISABLE
      *
      * PARAMETERS
      *      N/A
      *
      *
      * DESCRIPTION
      *      This function creates a deferred cancellation point
      *      in the calling thread. The call has no effect if the
      *      current cancelability state is
      *              PTHREAD_CANCEL_DISABLE
      *
      *      NOTES:
      *      1)      Cancellation is asynchronous. Use pthread_join
      *              to wait for termination of thread if necessary
      *
      * RESULTS
      *              N/A
      *
      * ------------------------------------------------------
      */
{
  __ptw32_mcs_local_node_t stateLock;
  pthread_t self = pthread_self ();
  __ptw32_thread_t * sp = (__ptw32_thread_t *) self.p;

  if (sp == NULL)
    {
      return;
    }

  /*
   * Pthread_cancel() will have set sp->state to PThreadStateCancelPending
   * and set an event, so no need to enter kernel space if
   * sp->state != PThreadStateCancelPending - that only slows us down.
   */
  if (sp->state != PThreadStateCancelPending)
    {
      return;
    }

  __ptw32_mcs_lock_acquire (&sp->stateLock, &stateLock);

  if (sp->cancelState != PTHREAD_CANCEL_DISABLE)
    {
      ResetEvent(sp->cancelEvent);
      sp->state = PThreadStateCanceling;
      sp->cancelState = PTHREAD_CANCEL_DISABLE;
      __ptw32_mcs_lock_release (&stateLock);
      __ptw32_throw  (__PTW32_EPS_CANCEL);
      /* Never returns here */
    }

  __ptw32_mcs_lock_release (&stateLock);
}				/* pthread_testcancel */