nuttx/libs/libc/unistd/lib_setpriority.c

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/****************************************************************************
* libs/libc/unistd/lib_setpriority.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sched.h>
#include <errno.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: setpriority
*
* Description:
* The setpriority() function shall set the nice value of a process,
* process group, or user to value+ {NZERO}.
*
* Input Parameters:
* which - PRIO_PROCESS, PRIO_PGRP, or PRIO_USER, ignored in current
* implementation.
* who - Process id is interpreted relative to "which"
* value - Value in the range SCHED_PRIORITY_MIN to SCHED_PRIORITY_MAX
*
* Returned Value:
* Upon successful completion, setpriority() shall return 0; otherwise,
* -1 shall be returned and errno set to indicate the error.
*
* Assumptions:
*
****************************************************************************/
int setpriority(int which, id_t who, int value)
{
struct sched_param param;
int ret;
if (who == 0)
{
who = getpid();
}
ret = sched_getparam(who, &param);
if (ret < 0)
{
return ret;
}
param.sched_priority = value;
return sched_setparam(who, &param);
}