* libs/libc/time/lib_dayofweek.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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 <stdint.h>
#include <stdbool.h>
#include <nuttx/clock.h>
* Pre-processor Definitions
****************************************************************************/
* Private Type Declarations
****************************************************************************/
* Private Function Prototypes
****************************************************************************/
* Public Constant Data
****************************************************************************/
* Public Data
****************************************************************************/
* Private Data
****************************************************************************/
* Private Functions
****************************************************************************/
* Public Functions
****************************************************************************/
* Name: clock_dayoftheweek
*
* Description:
* Get the day of the week
*
* Input Parameters:
* mday - The day of the month 1 - 31
* month - The month of the year 1 - 12
* year - the year including the 1900
*
* Returned Value:
* Zero based day of the week 0-6, 0 = Sunday, 1 = Monday... 6 = Saturday
*
****************************************************************************/
int clock_dayoftheweek(int mday, int month, int year)
{
if (month <= 2)
{
year--;
month += 12;
}
month -= 2;
return (mday + year + year / 4 - year / 100 + year / 400 +
(31 * month) / 12) % 7;
}