| /* clock_getres -- Get the resolution of a POSIX clockid_t. |
| Copyright (C) 1999,2000,2001,2003,2004,2008 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| #include <errno.h> |
| #include <stdint.h> |
| #include <time.h> |
| #include <unistd.h> |
| #include <sys/param.h> |
| #include <libc-internal.h> |
| |
| |
| #if HP_TIMING_AVAIL |
| static long int nsec; /* Clock frequency of the processor. */ |
| |
| static int |
| hp_timing_getres (struct timespec *res) |
| { |
| if (__builtin_expect (nsec == 0, 0)) |
| { |
| hp_timing_t freq; |
| |
| /* This can only happen if we haven't initialized the `nsec' |
| variable yet. Do this now. We don't have to protect this |
| code against multiple execution since all of them should |
| lead to the same result. */ |
| freq = __get_clockfreq (); |
| if (__builtin_expect (freq == 0, 0)) |
| /* Something went wrong. */ |
| return -1; |
| |
| nsec = MAX (UINT64_C (1000000000) / freq, 1); |
| } |
| |
| /* Fill in the values. |
| The seconds are always zero (unless we have a 1Hz machine). */ |
| res->tv_sec = 0; |
| res->tv_nsec = nsec; |
| |
| return 0; |
| } |
| #endif |
| |
| static inline int |
| realtime_getres (struct timespec *res) |
| { |
| long int clk_tck = sysconf (_SC_CLK_TCK); |
| |
| if (__builtin_expect (clk_tck != -1, 1)) |
| { |
| /* This implementation assumes that the realtime clock has a |
| resolution higher than 1 second. This is the case for any |
| reasonable implementation. */ |
| res->tv_sec = 0; |
| res->tv_nsec = 1000000000 / clk_tck; |
| return 0; |
| } |
| |
| return -1; |
| } |
| |
| |
| /* Get resolution of clock. */ |
| int |
| clock_getres (clockid_t clock_id, struct timespec *res) |
| { |
| int retval = -1; |
| |
| switch (clock_id) |
| { |
| #ifdef SYSDEP_GETRES |
| SYSDEP_GETRES; |
| #endif |
| |
| #ifndef HANDLED_REALTIME |
| case CLOCK_REALTIME: |
| retval = realtime_getres (res); |
| break; |
| #endif /* handled REALTIME */ |
| |
| default: |
| #ifdef SYSDEP_GETRES_CPU |
| SYSDEP_GETRES_CPU; |
| #endif |
| #if HP_TIMING_AVAIL |
| if ((clock_id & ((1 << CLOCK_IDFIELD_SIZE) - 1)) |
| == CLOCK_THREAD_CPUTIME_ID) |
| retval = hp_timing_getres (res); |
| else |
| #endif |
| __set_errno (EINVAL); |
| break; |
| |
| #if HP_TIMING_AVAIL && !defined HANDLED_CPUTIME |
| case CLOCK_PROCESS_CPUTIME_ID: |
| case CLOCK_THREAD_CPUTIME_ID: |
| retval = hp_timing_getres (res); |
| break; |
| #endif |
| } |
| |
| return retval; |
| } |