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sched_get_priority_max.c
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sched_get_priority_max.c
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/*
* sched_get_priority_max.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"
/*
* On Windows98, THREAD_PRIORITY_LOWEST is (-2) and
* THREAD_PRIORITY_HIGHEST is 2, and everything works just fine.
*
* On WinCE 3.0, it so happen that THREAD_PRIORITY_LOWEST is 5
* and THREAD_PRIORITY_HIGHEST is 1 (yes, I know, it is funny:
* highest priority use smaller numbers) and the following happens:
*
* sched_get_priority_min() returns 5
* sched_get_priority_max() returns 1
*
* The following table shows the base priority levels for combinations
* of priority class and priority value in Win32.
*
* Process Priority Class Thread Priority Level
* -----------------------------------------------------------------
* 1 IDLE_PRIORITY_CLASS THREAD_PRIORITY_IDLE
* 1 BELOW_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_IDLE
* 1 NORMAL_PRIORITY_CLASS THREAD_PRIORITY_IDLE
* 1 ABOVE_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_IDLE
* 1 HIGH_PRIORITY_CLASS THREAD_PRIORITY_IDLE
* 2 IDLE_PRIORITY_CLASS THREAD_PRIORITY_LOWEST
* 3 IDLE_PRIORITY_CLASS THREAD_PRIORITY_BELOW_NORMAL
* 4 IDLE_PRIORITY_CLASS THREAD_PRIORITY_NORMAL
* 4 BELOW_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_LOWEST
* 5 IDLE_PRIORITY_CLASS THREAD_PRIORITY_ABOVE_NORMAL
* 5 BELOW_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_BELOW_NORMAL
* 5 Background NORMAL_PRIORITY_CLASS THREAD_PRIORITY_LOWEST
* 6 IDLE_PRIORITY_CLASS THREAD_PRIORITY_HIGHEST
* 6 BELOW_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_NORMAL
* 6 Background NORMAL_PRIORITY_CLASS THREAD_PRIORITY_BELOW_NORMAL
* 7 BELOW_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_ABOVE_NORMAL
* 7 Background NORMAL_PRIORITY_CLASS THREAD_PRIORITY_NORMAL
* 7 Foreground NORMAL_PRIORITY_CLASS THREAD_PRIORITY_LOWEST
* 8 BELOW_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_HIGHEST
* 8 NORMAL_PRIORITY_CLASS THREAD_PRIORITY_ABOVE_NORMAL
* 8 Foreground NORMAL_PRIORITY_CLASS THREAD_PRIORITY_BELOW_NORMAL
* 8 ABOVE_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_LOWEST
* 9 NORMAL_PRIORITY_CLASS THREAD_PRIORITY_HIGHEST
* 9 Foreground NORMAL_PRIORITY_CLASS THREAD_PRIORITY_NORMAL
* 9 ABOVE_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_BELOW_NORMAL
* 10 Foreground NORMAL_PRIORITY_CLASS THREAD_PRIORITY_ABOVE_NORMAL
* 10 ABOVE_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_NORMAL
* 11 Foreground NORMAL_PRIORITY_CLASS THREAD_PRIORITY_HIGHEST
* 11 ABOVE_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_ABOVE_NORMAL
* 11 HIGH_PRIORITY_CLASS THREAD_PRIORITY_LOWEST
* 12 ABOVE_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_HIGHEST
* 12 HIGH_PRIORITY_CLASS THREAD_PRIORITY_BELOW_NORMAL
* 13 HIGH_PRIORITY_CLASS THREAD_PRIORITY_NORMAL
* 14 HIGH_PRIORITY_CLASS THREAD_PRIORITY_ABOVE_NORMAL
* 15 HIGH_PRIORITY_CLASS THREAD_PRIORITY_HIGHEST
* 15 HIGH_PRIORITY_CLASS THREAD_PRIORITY_TIME_CRITICAL
* 15 IDLE_PRIORITY_CLASS THREAD_PRIORITY_TIME_CRITICAL
* 15 BELOW_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_TIME_CRITICAL
* 15 NORMAL_PRIORITY_CLASS THREAD_PRIORITY_TIME_CRITICAL
* 15 ABOVE_NORMAL_PRIORITY_CLASS THREAD_PRIORITY_TIME_CRITICAL
* 16 REALTIME_PRIORITY_CLASS THREAD_PRIORITY_IDLE
* 17 REALTIME_PRIORITY_CLASS -7
* 18 REALTIME_PRIORITY_CLASS -6
* 19 REALTIME_PRIORITY_CLASS -5
* 20 REALTIME_PRIORITY_CLASS -4
* 21 REALTIME_PRIORITY_CLASS -3
* 22 REALTIME_PRIORITY_CLASS THREAD_PRIORITY_LOWEST
* 23 REALTIME_PRIORITY_CLASS THREAD_PRIORITY_BELOW_NORMAL
* 24 REALTIME_PRIORITY_CLASS THREAD_PRIORITY_NORMAL
* 25 REALTIME_PRIORITY_CLASS THREAD_PRIORITY_ABOVE_NORMAL
* 26 REALTIME_PRIORITY_CLASS THREAD_PRIORITY_HIGHEST
* 27 REALTIME_PRIORITY_CLASS 3
* 28 REALTIME_PRIORITY_CLASS 4
* 29 REALTIME_PRIORITY_CLASS 5
* 30 REALTIME_PRIORITY_CLASS 6
* 31 REALTIME_PRIORITY_CLASS THREAD_PRIORITY_TIME_CRITICAL
*
* Windows NT: Values -7, -6, -5, -4, -3, 3, 4, 5, and 6 are not supported.
*/
int
sched_get_priority_max (int policy)
{
if (policy < SCHED_MIN || policy > SCHED_MAX)
{
errno = EINVAL;
return -1;
}
#if (THREAD_PRIORITY_LOWEST > THREAD_PRIORITY_NORMAL)
/* WinCE? */
return PTW32_MAX (THREAD_PRIORITY_IDLE, THREAD_PRIORITY_TIME_CRITICAL);
#else
/* This is independent of scheduling policy in Win32. */
return PTW32_MAX (THREAD_PRIORITY_IDLE, THREAD_PRIORITY_TIME_CRITICAL);
#endif
}