/* SPDX-License-Identifier: BSD-2-Clause */

/**
 * @file
 *
 * @ingroup POSIXAPI
 *
 * @brief Function Returns the Resolution of any Clock
 */

/*
 *  COPYRIGHT (c) 1989-2007.
 *  On-Line Applications Research Corporation (OAR).
 *
 * 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.
 *
 * 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <time.h>
#include <errno.h>

#include <rtems/score/todimpl.h>
#include <rtems/config.h>
#include <rtems/seterr.h>

/*
 *  14.2.1 Clocks, P1003.1b-1993, p. 263
 */

int clock_getres(
  clockid_t        clock_id,
  struct timespec *res
)
{
  if ( !res )
    rtems_set_errno_and_return_minus_one( EINVAL );

  switch ( clock_id ) {

    /*
     *  All time in rtems is based on the same clock tick.
     */

    case CLOCK_REALTIME:
    case CLOCK_PROCESS_CPUTIME_ID:
    case CLOCK_THREAD_CPUTIME_ID:
      if ( res ) {
        res->tv_sec = rtems_configuration_get_microseconds_per_tick() /
            TOD_MICROSECONDS_PER_SECOND;
        res->tv_nsec = rtems_configuration_get_nanoseconds_per_tick();
      }
      break;

    default:
      rtems_set_errno_and_return_minus_one( EINVAL );

  }
  return 0;
}