time.h 2.4 KB

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  1. /* System-dependent timing definitions. Generic version.
  2. Copyright (C) 1996-2019 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, see
  14. <http://www.gnu.org/licenses/>. */
  15. /*
  16. * Never include this file directly; use <time.h> instead.
  17. */
  18. #ifndef _BITS_TIME_H
  19. #define _BITS_TIME_H 1
  20. #include <bits/types.h>
  21. /* ISO/IEC 9899:1999 7.23.1: Components of time
  22. The macro `CLOCKS_PER_SEC' is an expression with type `clock_t' that is
  23. the number per second of the value returned by the `clock' function. */
  24. /* CAE XSH, Issue 4, Version 2: <time.h>
  25. The value of CLOCKS_PER_SEC is required to be 1 million on all
  26. XSI-conformant systems. */
  27. #define CLOCKS_PER_SEC ((__clock_t) 1000000)
  28. #if (!defined __STRICT_ANSI__ || defined __USE_POSIX) \
  29. && !defined __USE_XOPEN2K
  30. /* Even though CLOCKS_PER_SEC has such a strange value CLK_TCK
  31. presents the real value for clock ticks per second for the system. */
  32. extern long int __sysconf (int);
  33. # define CLK_TCK ((__clock_t) __sysconf (2)) /* 2 is _SC_CLK_TCK */
  34. #endif
  35. #ifdef __USE_POSIX199309
  36. /* Identifier for system-wide realtime clock. */
  37. # define CLOCK_REALTIME 0
  38. /* Monotonic system-wide clock. */
  39. # define CLOCK_MONOTONIC 1
  40. /* High-resolution timer from the CPU. */
  41. # define CLOCK_PROCESS_CPUTIME_ID 2
  42. /* Thread-specific CPU-time clock. */
  43. # define CLOCK_THREAD_CPUTIME_ID 3
  44. /* Monotonic system-wide clock, not adjusted for frequency scaling. */
  45. # define CLOCK_MONOTONIC_RAW 4
  46. /* Identifier for system-wide realtime clock, updated only on ticks. */
  47. # define CLOCK_REALTIME_COARSE 5
  48. /* Monotonic system-wide clock, updated only on ticks. */
  49. # define CLOCK_MONOTONIC_COARSE 6
  50. /* Flag to indicate time is absolute. */
  51. # define TIMER_ABSTIME 1
  52. #endif
  53. #endif /* bits/time.h */