libc/sysdeps/linux/common/clock_getres.c

   1 /*
   2  * clock_getres() for uClibc
   3  *
   4  * Copyright (C) 2005 by Peter Kjellerstedt <pkj@axis.com>
   5  * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
   6  *
   7  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
   8  */
   9
  10 #include <sys/syscall.h>
  11 #include <time.h>
  12
  13 #if defined(__UCLIBC_USE_TIME64__) && defined(__NR_clock_getres_time64)
  14 #include "internal/time64_helpers.h"
  15
  16 int clock_getres(clockid_t clock_id, struct timespec *res)
  17 {
  18         struct __ts64_struct __ts64;
  19         int __ret = INLINE_SYSCALL(clock_getres_time64, 2, clock_id, &__ts64);
  20         if (__ret == 0 && res) {
  21                 res->tv_sec = __ts64.tv_sec;
  22                 res->tv_nsec = __ts64.tv_nsec;
  23         };
  24
  25         return __ret;
  26 }
  27 #elif defined(__NR_clock_getres)
  28 _syscall2(int, clock_getres, clockid_t, clock_id, struct timespec*, res)
  29 #else
  30 # include <unistd.h>
  31
  32 int clock_getres(clockid_t clock_id, struct timespec* res)
  33 {
  34         int retval = -1;
  35
  36         switch (clock_id) {
  37                 case CLOCK_REALTIME:
  38                         if (res) {
  39                                 long clk_tck;
  40
  41                                 if ((clk_tck = sysconf(_SC_CLK_TCK)) < 0)
  42                                         clk_tck = 100;
  43                                 res->tv_sec = 0;
  44                                 res->tv_nsec = 1000000000 / clk_tck;
  45                         }
  46                         retval = 0;
  47                         break;
  48
  49                 default:
  50                         errno = EINVAL;
  51                         break;
  52         }
  53
  54         return retval;
  55 }
  56 #endif
  57 libc_hidden_def(clock_getres)