text: /****************************************************************************
   * sched/pthread/pthread_setschedprio.c
   *
   *   Copyright (C) 2007, 2009, 2015 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  #include <sys/types.h>
  #include <sched.h>
  #include <errno.h>
  #include <nuttx/arch.h>
  #include "sched/sched.h"
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  /****************************************************************************
   * Private Type Declarations
   ****************************************************************************/
  
  /****************************************************************************
   * Global Variables
   ****************************************************************************/
  
  /****************************************************************************
   * Private Variables
   ****************************************************************************/
  
  /****************************************************************************
   * Private Function Prototypes
   ****************************************************************************/
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name:  pthread_setsetprio
   *
   * Description:
   *   The pthread_setschedprio() function sets the scheduling priority for the
   *   thread whose thread ID is given by 'thread' to the value given by 'prio'.
   *   If the  thread_setschedprio() function fails, the scheduling priority
   *   of the target thread will not be changed.
   *
   * Inputs:
   *   thread - the thread ID of the task to reprioritize.
   *   prio - The new thread priority.  The range of valid priority numbers is
   *     from SCHED_PRIORITY_MIN through SCHED_PRIORITY_MAX.
   *
   * Return Value:
   *    OK if successful, otherwise an error number.  This function can
   *    fail for the following reasons:
   *
   *    EINVAL - prio is out of range.
   *    ESRCH  - thread ID does not correspond to any thread.
   *
   * Assumptions:
   *
   ****************************************************************************/
  
  int pthread_setschedprio(pthread_t thread, int prio)
  {
    struct sched_param param;
    int ret;
  
  #ifdef CONFIG_SCHED_SPORADIC
    /* Get the current sporadic scheduling parameters.  Those will not be
     * modified.
     */
  
    ret = sched_getparam((pid_t)thread, &param);
    if (ret < 0)
      {
        goto errout_with_errno;
      }
  #endif
  
    /* Call sched_setparam() to change the priority */
  
    param.sched_priority = prio;
    ret = sched_setparam((pid_t)thread, &param);
    if (ret >= 0)
      {
        return OK;
      }
  
  #ifdef CONFIG_SCHED_SPORADIC
  errout_with_errno:
  #endif
    ret = get_errno();
    return ret;
  }
  