46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
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/*
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* Copyright (c) 1983 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that: (1) source distributions retain this entire copyright
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* notice and comment, and (2) distributions including binaries display
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* the following acknowledgement: ``This product includes software
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* developed by the University of California, Berkeley and its contributors''
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* in the documentation or other materials provided with the distribution
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* and in all advertising materials mentioning features or use of this
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* software. Neither the name of the University nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)hertz.c 5.4 (Berkeley) 6/1/90";
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#endif /* not lint */
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#include <sys/time.h>
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/*
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* discover the tick frequency of the machine
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* if something goes wrong, we return 0, an impossible hertz.
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*/
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#define HZ_WRONG 0
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hertz()
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{
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struct itimerval tim;
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tim.it_interval.tv_sec = 0;
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tim.it_interval.tv_usec = 1;
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tim.it_value.tv_sec = 0;
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tim.it_value.tv_usec = 0;
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setitimer(ITIMER_REAL, &tim, 0);
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setitimer(ITIMER_REAL, 0, &tim);
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if (tim.it_interval.tv_usec < 2)
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return(HZ_WRONG);
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return (1000000 / tim.it_interval.tv_usec);
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}
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