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3d6c6501 SEF |
1 | /* |
2 | * Copyright (c) 1983 Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms are permitted | |
6 | * provided that: (1) source distributions retain this entire copyright | |
7 | * notice and comment, and (2) distributions including binaries display | |
8 | * the following acknowledgement: ``This product includes software | |
9 | * developed by the University of California, Berkeley and its contributors'' | |
10 | * in the documentation or other materials provided with the distribution | |
11 | * and in all advertising materials mentioning features or use of this | |
12 | * software. Neither the name of the University nor the names of its | |
13 | * contributors may be used to endorse or promote products derived | |
14 | * from this software without specific prior written permission. | |
15 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
16 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
17 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
18 | */ | |
3d6c6501 | 19 | #include <sys/time.h> |
5489fcc3 | 20 | #include "hertz.h" |
3d6c6501 | 21 | |
3d6c6501 | 22 | |
c06e55d9 | 23 | #ifdef __MSDOS__ |
5489fcc3 | 24 | # define HERTZ 18 |
c06e55d9 KR |
25 | #endif |
26 | ||
5489fcc3 | 27 | int |
3d6c6501 SEF |
28 | hertz() |
29 | { | |
c06e55d9 | 30 | #ifdef HERTZ |
5489fcc3 | 31 | return HERTZ; |
c06e55d9 | 32 | #else |
5489fcc3 | 33 | struct itimerval tim; |
3d6c6501 | 34 | |
5489fcc3 KR |
35 | tim.it_interval.tv_sec = 0; |
36 | tim.it_interval.tv_usec = 1; | |
37 | tim.it_value.tv_sec = 0; | |
38 | tim.it_value.tv_usec = 0; | |
39 | setitimer(ITIMER_REAL, &tim, 0); | |
40 | setitimer(ITIMER_REAL, 0, &tim); | |
41 | if (tim.it_interval.tv_usec < 2) { | |
42 | return HZ_WRONG; | |
43 | } /* if */ | |
44 | return 1000000 / tim.it_interval.tv_usec; | |
c06e55d9 | 45 | #endif |
5489fcc3 | 46 | } /* hertz */ |