1 /*
2 * (C)2012 Michael Duane Rice All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 * Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer. Redistributions in binary
10 * form must reproduce the above copyright notice, this list of conditions
11 * and the following disclaimer in the documentation and/or other materials
12 * provided with the distribution. Neither the name of the copyright holders
13 * nor the names of contributors may be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /* $Id: lm_sidereal.c 2326 2013-04-02 21:23:41Z swfltek $ */
30
31 /*
32 Local Mean Sidereal Time. See gm_sidereal() for info.
33 */
34 #include <time.h>
35
36 extern long __longitude;
37
38 unsigned long
lm_sidereal(const time_t * timer)39 lm_sidereal(const time_t * timer)
40 {
41 long n;
42
43 n = gm_sidereal(timer) + __longitude / 15L;
44 n += ONE_DAY;
45 n %= ONE_DAY;
46 return n;
47 }
48