65 lines
2.5 KiB
C
65 lines
2.5 KiB
C
/****************************************************************************
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* sched/clock/clock.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <time.h>
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#include <nuttx/clock.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: clock
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*
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* Description:
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* The clock() function returns the implementation's best approximation to
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* the processor time used by the process since the beginning of a
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* implementation-defined era related only to the process invocation.
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*
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* To determine the time in seconds, the value returned by clock() should
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* be divided by the value of the macro CLOCKS_PER_SEC as defined in
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* <time.h>.
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*
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* NOTE: The current implementation does NOT return the processor time
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* used by the process. NuttX currently does not keep any record of
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* processing time. Instead the elapsed time since power up is returned.
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*
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* Input Parameters:
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* None
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*
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* Returned Value:
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* The system time in units of clock ticks is returned. If the processor
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* time used is not available or its value cannot be represented, the
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* function will return the value (clock_t)-1.
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*
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****************************************************************************/
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clock_t clock(void)
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{
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return (clock_t)clock_systime_ticks();
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}
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