text: /********************************************************************************
   * sched/timer/timer_gettime.c
   *
   *   Copyright (C) 2007 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 <time.h>
  #include <errno.h>
  
  #include "clock/clock.h"
  #include "timer/timer.h"
  
  #ifndef CONFIG_DISABLE_POSIX_TIMERS
  
  /********************************************************************************
   * Public Functions
   ********************************************************************************/
  
  /********************************************************************************
   * Name: timer_gettime
   *
   * Description:
   *  The timer_gettime() function will store the amount of time until the
   *  specified timer, timerid, expires and the reload value of the timer into the
   *  space pointed to by the value argument. The it_value member of this structure
   *  will contain the amount of time before the timer expires, or zero if the timer
   *  is disarmed. This value is returned as the interval until timer expiration,
   *  even if the timer was armed with absolute time. The it_interval member of
   *  value will contain the reload value last set by timer_settime().
   *
   * Parameters:
   *   timerid - The pre-thread timer, previously created by the call to
   *   timer_create(), whose remaining time count will be returned..
   *
   * Return Value:
   *   If the timer_gettime() succeeds, a value of 0 (OK) will be returned.
   *   If an error occurs, the value -1 (ERROR) will be returned, and errno set to
   *   indicate the error.
   *
   *   EINVAL - The timerid argument does not correspond to an ID returned by
   *     timer_create() but not yet deleted by timer_delete().
   *
   * Assumptions/Limitations:
   *   Due to the asynchronous operation of this function, the time reported
   *   by this function could be significantly more than that actual time
   *   remaining on the timer at any time.
   *
   ********************************************************************************/
  
  int timer_gettime(timer_t timerid, FAR struct itimerspec *value)
  {
    FAR struct posix_timer_s *timer = (FAR struct posix_timer_s *)timerid;
    int ticks;
  
    if (!timer || !value)
      {
        set_errno(EINVAL);
        return ERROR;
      }
  
    /* Get the number of ticks before the underlying watchdog expires */
  
    ticks = wd_gettime(timer->pt_wdog);
  
    /* Convert that to a struct timespec and return it */
  
    (void)clock_ticks2time(ticks, &value->it_value);
    (void)clock_ticks2time(timer->pt_last, &value->it_interval);
    return OK;
  }
  
  #endif /* CONFIG_DISABLE_POSIX_TIMERS */
  