pthread_delay_np.c

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

/*
 * 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 cancelation 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 = 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 cancelation won't catch us until wait_time is up.
       * Deferred cancelation will cancel us immediately.
       */
      if (WAIT_OBJECT_0 ==
	  (status = WaitForSingleObject (sp->cancelEvent, wait_time)))
	{
	  /*
	   * Canceling!
	   */
	  (void) pthread_mutex_lock (&sp->cancelLock);
	  if (sp->state < PThreadStateCanceling)
	    {
	      sp->state = PThreadStateCanceling;
	      sp->cancelState = PTHREAD_CANCEL_DISABLE;
	      (void) pthread_mutex_unlock (&sp->cancelLock);

	      ptw32_throw (PTW32_EPS_CANCEL);
	    }

	  (void) pthread_mutex_unlock (&sp->cancelLock);
	  return ESRCH;
	}
      else if (status != WAIT_TIMEOUT)
	{
	  return EINVAL;
	}
    }
  else
    {
      Sleep (wait_time);
    }

  return (0);
}