pthread_delay_np.c

/*
 * pthreads_delay_np.c
 *
 * Description:
 * This translation unit implements non-portable thread functions.
 *
 * --------------------------------------------------------------------------
 *
 *      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"

/*
 * pthread_delay_np
 *
 * DESCRIPTION
 *
 *       This routine causes a thread to delay execution for a specific period of time.
 *       This period ends at the current time plus the specified interval. The routine
 *       will not return before the end of the period is reached, but may return an
 *       arbitrary amount of time after the period has gone by. This can be due to
 *       system load, thread priorities, and system timer granularity. 
 *
 *       Specifying an interval of zero (0) seconds and zero (0) nanoseconds is
 *       allowed and can be used to force the thread to give up the processor or to
 *       deliver a pending cancellation request. 
 *
 *       The timespec structure contains the following two fields: 
 *
 *            tv_sec is an integer number of seconds. 
 *            tv_nsec is an integer number of nanoseconds. 
 *
 *  Return Values
 *
 *  If an error condition occurs, this routine returns an integer value indicating
 *  the type of error. Possible return values are as follows: 
 *
 *  0 
 *           Successful completion.
 *  [EINVAL] 
 *           The value specified by interval is invalid. 
 *
 * Example
 *
 * The following code segment would wait for 5 and 1/2 seconds
 *
 *  struct timespec tsWait;
 *  int      intRC;
 *
 *  tsWait.tv_sec  = 5;
 *  tsWait.tv_nsec = 500000000L;
 *  intRC = pthread_delay_np(&tsWait);
 */
int
pthread_delay_np (struct timespec *interval)
{
  DWORD wait_time;
  DWORD secs_in_millisecs;
  DWORD millisecs;
  DWORD status;
  pthread_t self;
  __ptw32_thread_t * sp;

  if (interval == NULL)
    {
      return EINVAL;
    }

  if (interval->tv_sec == 0L && interval->tv_nsec == 0L)
    {
      pthread_testcancel ();
      Sleep (0);
      pthread_testcancel ();
      return (0);
    }

  /* convert secs to millisecs */
  secs_in_millisecs = (DWORD)interval->tv_sec * 1000L;

  /* convert nanosecs to millisecs (rounding up) */
  millisecs = (interval->tv_nsec + 999999L) / 1000000L;

#if defined(__WATCOMC__)
#pragma disable_message (124)
#endif

  /*
   * Most compilers will issue a warning 'comparison always 0'
   * because the variable type is unsigned, but we need to keep this
   * for some reason I can't recall now.
   */
  if (0 > (wait_time = secs_in_millisecs + millisecs))
    {
      return EINVAL;
    }

#if defined(__WATCOMC__)
#pragma enable_message (124)
#endif

  if (NULL == (self = pthread_self ()).p)
    {
      return ENOMEM;
    }

  sp = (__ptw32_thread_t *) self.p;

  if (sp->cancelState == PTHREAD_CANCEL_ENABLE)
    {
      /*
       * Async cancellation won't catch us until wait_time is up.
       * Deferred cancellation will cancel us immediately.
       */
      if (WAIT_OBJECT_0 ==
	  (status = WaitForSingleObject (sp->cancelEvent, wait_time)))
	{
          __ptw32_mcs_local_node_t stateLock;
	  /*
	   * Canceling!
	   */
	  __ptw32_mcs_lock_acquire (&sp->stateLock, &stateLock);
	  if (sp->state < PThreadStateCanceling)
	    {
	      sp->state = PThreadStateCanceling;
	      sp->cancelState = PTHREAD_CANCEL_DISABLE;
	      __ptw32_mcs_lock_release (&stateLock);

	      __ptw32_throw  (__PTW32_EPS_CANCEL);
	    }

	  __ptw32_mcs_lock_release (&stateLock);
	  return ESRCH;
	}
      else if (status != WAIT_TIMEOUT)
	{
	  return EINVAL;
	}
    }
  else
    {
      Sleep (wait_time);
    }

  return (0);
}