| 1 | /*
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| 2 | * Copyright (c) 1983 Regents of the University of California.
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms are permitted
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| 6 | * provided that: (1) source distributions retain this entire copyright
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| 7 | * notice and comment, and (2) distributions including binaries display
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| 8 | * the following acknowledgement: ``This product includes software
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| 9 | * developed by the University of California, Berkeley and its contributors''
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| 10 | * in the documentation or other materials provided with the distribution
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| 11 | * and in all advertising materials mentioning features or use of this
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| 12 | * software. Neither the name of the University nor the names of its
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| 13 | * contributors may be used to endorse or promote products derived
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| 14 | * from this software without specific prior written permission.
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| 15 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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| 16 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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| 17 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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| 18 | */
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| 19 | #include "hertz.h"
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| 20 |
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| 21 |
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| 22 | int
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| 23 | hertz ()
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| 24 | {
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| 25 | #ifdef HERTZ
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| 26 | return HERTZ;
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| 27 | #else /* ! defined (HERTZ) */
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| 28 | #ifdef HAVE_SETITIMER
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| 29 | struct itimerval tim;
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| 30 |
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| 31 | tim.it_interval.tv_sec = 0;
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| 32 | tim.it_interval.tv_usec = 1;
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| 33 | tim.it_value.tv_sec = 0;
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| 34 | tim.it_value.tv_usec = 0;
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| 35 | setitimer (ITIMER_REAL, &tim, 0);
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| 36 | setitimer (ITIMER_REAL, 0, &tim);
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| 37 | if (tim.it_interval.tv_usec >= 2)
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| 38 | {
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| 39 | return 1000000 / tim.it_interval.tv_usec;
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| 40 | }
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| 41 | #endif /* ! defined (HAVE_SETITIMER) */
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| 42 | #if defined (HAVE_SYSCONF) && defined (_SC_CLK_TCK)
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| 43 | return sysconf (_SC_CLK_TCK);
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| 44 | #else /* ! defined (HAVE_SYSCONF) || ! defined (_SC_CLK_TCK) */
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| 45 | #ifdef __MSDOS__
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| 46 | return 18;
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| 47 | #else /* ! defined (__MSDOS__) */
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| 48 | return HZ_WRONG;
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| 49 | #endif /* ! defined (__MSDOS__) */
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| 50 | #endif /* ! defined (HAVE_SYSCONF) || ! defined (_SC_CLK_TCK) */
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| 51 | #endif /* ! defined (HERTZ) */
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| 52 | }
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