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/*
* sched.c
*
* Description:
* POSIX thread functions that deal with thread scheduling.
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright (C) 1998
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA
*/
/*
* If ENOTSUP is not defined, define it to a value that will never occur.
* This is the value used in the Win32 TCL port.
*/
#include "pthread.h"
#include "implement.h"
#include "sched.h"
static int
is_attr(const pthread_attr_t *attr)
{
return (attr == NULL ||
*attr == NULL ||
(*attr)->valid != PTW32_ATTR_VALID) ? 1 : 0;
}
int
pthread_attr_setschedparam(pthread_attr_t *attr,
const struct sched_param *param)
{
if (is_attr(attr) != 0 || param == NULL)
{
return EINVAL;
}
(*attr)->priority = param->sched_priority;
return 0;
}
int
pthread_attr_getschedparam(const pthread_attr_t *attr,
struct sched_param *param)
{
if (is_attr(attr) != 0 || param == NULL)
{
return EINVAL;
}
param->sched_priority = (*attr)->priority;
return 0;
}
int
pthread_setschedparam(pthread_t thread, int policy,
const struct sched_param *param)
{
/* Validate the thread id. */
if (thread == NULL || thread->threadH == 0)
{
return EINVAL;
}
/* 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;
}
/* Validate priority level. */
if (param->sched_priority < sched_get_priority_min(policy) ||
param->sched_priority > sched_get_priority_max(policy))
{
return EINVAL;
}
/* This is practically guaranteed to return TRUE. */
(void) SetThreadPriority(thread->threadH, param->sched_priority);
return 0;
}
int
pthread_getschedparam(pthread_t thread, int *policy,
struct sched_param *param)
{
int prio;
/* Validate the thread id. */
if (thread == NULL || thread->threadH == 0)
{
return EINVAL;
}
/* Validate the param structure. */
if (param == NULL)
{
return EINVAL;
}
/* Fill out the policy. */
*policy = SCHED_OTHER;
/* Fill out the sched_param structure. */
prio = GetThreadPriority(thread->threadH);
if (prio == THREAD_PRIORITY_ERROR_RETURN)
{
return EINVAL;
}
param->sched_priority = prio;
return 0;
}
/*
* 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
*/
#define sched_Max(a,b) ((a)<(b)?(b):(a))
#define sched_Min(a,b) ((a)>(b)?(b):(a))
int
sched_get_priority_max(int policy)
{
if (policy < SCHED_MIN || policy > SCHED_MAX)
{
return EINVAL;
}
#if (THREAD_PRIORITY_LOWEST > THREAD_PRIORITY_NORMAL)
/* WinCE? */
return sched_Max(THREAD_PRIORITY_IDLE, THREAD_PRIORITY_TIME_CRITICAL);
#else
/* This is independent of scheduling policy in Win32. */
return sched_Max(THREAD_PRIORITY_LOWEST, THREAD_PRIORITY_HIGHEST);
#endif
}
int
sched_get_priority_min(int policy)
{
if (policy < SCHED_MIN || policy > SCHED_MAX)
{
return EINVAL;
}
#if (THREAD_PRIORITY_LOWEST > THREAD_PRIORITY_NORMAL)
/* WinCE? */
return sched_Min(THREAD_PRIORITY_IDLE, THREAD_PRIORITY_TIME_CRITICAL);
#else
/* This is independent of scheduling policy in Win32. */
return sched_Min(THREAD_PRIORITY_LOWEST, THREAD_PRIORITY_HIGHEST);
#endif
}
int
sched_yield(void)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function indicates that the calling thread is
* willing to give up some time slices to other threads.
*
* PARAMETERS
* N/A
*
*
* DESCRIPTION
* This function indicates that the calling thread is
* willing to give up some time slices to other threads.
* NOTE: Since this is part of POSIX 1003.1b
* (realtime extensions), it is defined as returning
* -1 if an error occurs and sets errno to the actual
* error.
*
* RESULTS
* 0 successfully created semaphore,
* ENOSYS sched_yield not supported,
*
* ------------------------------------------------------
*/
{
Sleep(0);
return 0;
}