nuttx/sched/clock/clock.c
Alin Jerpelea 8935ac4cc3 sched: Author Gregory Nutt: update licenses to Apache
Gregory Nutt has submitted the SGA and we can mograte the licenses
to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-02-09 01:21:53 -08:00

65 lines
2.5 KiB
C

/****************************************************************************
* sched/clock/clock.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 <time.h>
#include <nuttx/clock.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: clock
*
* Description:
* The clock() function returns the implementation's best approximation to
* the processor time used by the process since the beginning of a
* implementation-defined era related only to the process invocation.
*
* To determine the time in seconds, the value returned by clock() should
* be divided by the value of the macro CLOCKS_PER_SEC as defined in
* <time.h>.
*
* NOTE: The current implementation does NOT return the processor time
* used by the process. NuttX currently does not keep any record of
* processing time. Instead the elapsed time since power up is returned.
*
* Input Parameters:
* None
*
* Returned Value:
* The system time in units of clock ticks is returned. If the processor
* time used is not available or its value cannot be represented, the
* function will return the value (clock_t)-1.
*
****************************************************************************/
clock_t clock(void)
{
return (clock_t)clock_systime_ticks();
}