[444] | 1 | /* Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library; if not, write to the Free |
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| 16 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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| 17 | 02111-1307 USA. */ |
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| 18 | |
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| 19 | #include <errno.h> |
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| 20 | #include <stdint.h> |
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| 21 | #include <time.h> |
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| 22 | #include <unistd.h> |
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| 23 | #include <sys/param.h> |
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| 24 | #include <libc-internal.h> |
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| 25 | |
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| 26 | |
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| 27 | #if HP_TIMING_AVAIL |
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| 28 | /* Clock frequency of the processor. */ |
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| 29 | static long int nsec; |
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| 30 | #endif |
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| 31 | |
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| 32 | |
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| 33 | /* Get resolution of clock. */ |
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| 34 | int |
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| 35 | clock_getres (clockid_t clock_id, struct timespec *res) |
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| 36 | { |
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| 37 | int retval = -1; |
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| 38 | |
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| 39 | switch (clock_id) |
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| 40 | { |
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| 41 | case CLOCK_REALTIME: |
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| 42 | { |
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| 43 | long int clk_tck = sysconf (_SC_CLK_TCK); |
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| 44 | |
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| 45 | if (__builtin_expect (clk_tck != -1, 1)) |
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| 46 | { |
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| 47 | /* This implementation assumes that the realtime clock has a |
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| 48 | resolution higher than 1 second. This is the case for any |
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| 49 | reasonable implementation. */ |
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| 50 | res->tv_sec = 0; |
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| 51 | res->tv_nsec = 1000000000 / clk_tck; |
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| 52 | |
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| 53 | retval = 0; |
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| 54 | } |
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| 55 | } |
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| 56 | break; |
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| 57 | |
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| 58 | #if HP_TIMING_AVAIL |
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| 59 | case CLOCK_PROCESS_CPUTIME_ID: |
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| 60 | case CLOCK_THREAD_CPUTIME_ID: |
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| 61 | { |
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| 62 | if (__builtin_expect (nsec == 0, 0)) |
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| 63 | { |
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| 64 | hp_timing_t freq; |
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| 65 | |
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| 66 | /* This can only happen if we haven't initialized the `freq' |
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| 67 | variable yet. Do this now. We don't have to protect this |
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| 68 | code against multiple execution since all of them should |
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| 69 | lead to the same result. */ |
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| 70 | freq = __get_clockfreq (); |
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| 71 | if (__builtin_expect (freq == 0, 0)) |
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| 72 | /* Something went wrong. */ |
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| 73 | break; |
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| 74 | |
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| 75 | nsec = MAX (UINT64_C (1000000000) / freq, 1); |
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| 76 | } |
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| 77 | |
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| 78 | /* File in the values. The seconds are always zero (unless we |
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| 79 | have a 1Hz machine). */ |
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| 80 | res->tv_sec = 0; |
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| 81 | res->tv_nsec = nsec; |
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| 82 | |
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| 83 | retval = 0; |
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| 84 | } |
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| 85 | break; |
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| 86 | #endif |
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| 87 | |
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| 88 | default: |
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| 89 | __set_errno (EINVAL); |
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| 90 | break; |
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| 91 | } |
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| 92 | |
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| 93 | return retval; |
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| 94 | } |
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