pthread_setschedparam.c

/*
 * sched_setschedparam.c
 * 
 * Description:
 * POSIX thread functions that deal with thread scheduling.
 *
 * --------------------------------------------------------------------------
 *
 *      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"
#include "sched.h"

int
pthread_setschedparam (pthread_t thread, int policy,
		       const struct sched_param *param)
{
  int result;

  /* Validate the thread id. */
  result = pthread_kill (thread, 0);
  if (0 != result)
    {
      return result;
    }

  /* Validate the scheduling policy. */
  if (policy < SCHED_MIN || policy > SCHED_MAX)
    {
      return EINVAL;
    }

  /* Ensure the policy is SCHED_OTHER. */
  if (policy != SCHED_OTHER)
    {
      return ENOTSUP;
    }

  return (ptw32_setthreadpriority (thread, policy, param->sched_priority));
}


int
ptw32_setthreadpriority (pthread_t thread, int policy, int priority)
{
  int prio;
  int result;
  ptw32_thread_t * tp = (ptw32_thread_t *) thread.p;

  prio = priority;

  /* Validate priority level. */
  if (prio < sched_get_priority_min (policy) ||
      prio > sched_get_priority_max (policy))
    {
      return EINVAL;
    }

#if (THREAD_PRIORITY_LOWEST > THREAD_PRIORITY_NORMAL)
/* WinCE */
#else
/* Everything else */

  if (THREAD_PRIORITY_IDLE < prio && THREAD_PRIORITY_LOWEST > prio)
    {
      prio = THREAD_PRIORITY_LOWEST;
    }
  else if (THREAD_PRIORITY_TIME_CRITICAL > prio
	   && THREAD_PRIORITY_HIGHEST < prio)
    {
      prio = THREAD_PRIORITY_HIGHEST;
    }

#endif

  result = pthread_mutex_lock (&tp->threadLock);

  if (0 == result)
    {
      /* If this fails, the current priority is unchanged. */
      if (0 == SetThreadPriority (tp->threadH, prio))
	{
	  result = EINVAL;
	}
      else
	{
	  /*
	   * Must record the thread's sched_priority as given,
	   * not as finally adjusted.
	   */
	  tp->sched_priority = priority;
	}

      (void) pthread_mutex_unlock (&tp->threadLock);
    }

  return result;
}