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52 lines
1.5 KiB
C
52 lines
1.5 KiB
C
/* Determine realtime clock frequency.
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Copyright (C) 2003, 2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <sys/time.h>
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#include <libc-internal.h>
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#include "kernel-features.h"
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#include <ldsodefs.h>
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int
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__profile_frequency (void)
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{
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#ifdef __ASSUME_AT_CLKTCK
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return GLRO(dl_clktck);
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#else
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if (GLRO(dl_clktck) != 0)
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return GLRO(dl_clktck);
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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 0;
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return 1000000 / tim.it_interval.tv_usec;
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#endif
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}
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libc_hidden_def (__profile_frequency)
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